Troubleshooting / 1336 and 1305 faults

Allen-Bradley 1336 and 1305 Fault Codes

The fault codes of the Allen-Bradley 1336 PLUS, 1336 PLUS II and 1305 drives, the older drives that still run conveyors, pumps and fans in many plants: what each code means, where the drives differ, the likely causes, the first checks in order, and how to log it.

How the 1336 and 1305 show faults

On a 1336 PLUS or 1336 PLUS II the HIM's LCD shows a short fault text such as Overload Fault, and a Series A (version 3.0) or Series B and later HIM shows it the moment it happens, whatever screen is open.

The Control Status menu holds a fault queue of the last four faults, where Trip marks the fault that actually stopped the drive, and Clear Queue empties the list but does not clear an active fault.

Once the cause is fixed you clear a 1336 fault by cycling drive power, by a valid Stop from the HIM or the TB3 stop input when [Flt Clear Mode] (parameter 39) is Enabled, which is the factory setting, or by a Clear Faults command from a serial device.

On a 1305 the HIM shows the fault text on line 1 and the fault number, such as F7, on line 2, the red Fault LED lights, [Fault Buffer 0] to [Fault Buffer 3] keep the last four faults, and you clear it by cycling power, cycling the stop signal or using [Clear Fault] (parameter 51), which also stops a running drive.

Automatic restart on all three drives is set with [Reset/Run Tries] (parameter 85, 0 to 9, default 0) and [Reset/Run Time] (parameter 15, 0.5 to 30 seconds, default 1.0 second), it only acts on faults the manual lists as resettable, and when the tries run out the drive trips on 33 Max Retries Fault.

Safety first.
The 1336 PLUS and 1336 PLUS II manuals say to verify that the bus capacitors have discharged before any work on the drive: measure the DC bus voltage at the + and - terminals of TB1, and it must read 0.0 V DC. The 1305 manual warns that DC bus voltage may still be present at TB1 after power is removed, so disconnect and lock out all input and control power, wait until the HIM is dark, check that the DC Bus charge neon indicator is off and then wait 60 seconds before touching the motor leads.

Both manuals say only people familiar with the drive and the machine it runs should install, start up or maintain it. Follow lockout/tagout and your site's safe-work procedures, and check the manual for your exact model before you act.

Quick lookup

Every code in this table is a fault that stops the drive and the motor, so in OEE each one is an availability loss until the drive is reset.

Type a number or a word (overvoltage, overload, ground fault, power loss) to filter the list. In the Drive column PLUS and PLUS II mean the 1336 PLUS and 1336 PLUS II; the 1305 shows the same numbers with an F in front (F7), and where a number means something different on one drive, that drive has its own row.

60 codes

CodeDriveName
02PLUS, PLUS IIAuxiliary Fault
03PLUS, PLUS II, 1305Power Loss Fault
04PLUS, PLUS II, 1305Undervolt Fault
05PLUS, PLUS II, 1305Overvolt Fault
06PLUSMotor Stall Fault (1336 PLUS)
06PLUS IIMotor Stall Fault (1336 PLUS II)
061305Motor Stall Fault (1305)
07PLUS, PLUS IIOverload Fault
071305Overload Fault (1305)
08PLUS, PLUS IIOvertemp Fault
081305Overtemp Fault (1305)
09PLUS, PLUS II, 1305Open Pot Fault
10PLUS, PLUS IISerial Fault
101305Serial Fault (1305)
11PLUS, PLUS IIOp Error Fault
111305Op Error Fault (1305)
12PLUS, PLUS II, 1305Overcurrent Flt
13PLUS, PLUS IIGround Fault
15PLUS IIMotor Thermistor
17PLUS IIC167 Watchdog
19PLUS, PLUS IIPrecharge Fault
20PLUS IILoad Loss Flt
22PLUS, PLUS II, 1305Drive Reset Fault (Drive Fault Reset on 1336 PLUS, DSP Reset Fault on 1336 PLUS II, Drive Reset Flt on 1305)
23PLUS, PLUS IILoop Overrn Flt
24PLUS, PLUS II, 1305Motor Mode Flt
26PLUS, PLUS II, 1305Power Mode Fault
29PLUS, PLUS II, 1305Hertz Err Fault (Hz Err Fault on 1305)
30PLUS, PLUS IIHertz Sel Fault
301305Hz Sel Fault (1305)
32PLUS, PLUS IIEEprom Fault
321305EEprom Fault (1305)
33PLUS, PLUS II, 1305Max Retries Fault
34PLUS, 1305Run Boost Fault
34PLUS IIPrm Access Flt (1336 PLUS II)
35PLUS, PLUS II, 1305Neg Slope Fault
36PLUS, PLUS IIDiag C Lim Flt
361305Diag C Lim Flt (1305)
38PLUS, PLUS II, 1305Phase U Fault
39PLUS, PLUS II, 1305Phase V Fault
40PLUS, PLUS II, 1305Phase W Fault
41PLUS, PLUS II, 1305UV Short Fault
42PLUS, PLUS II, 1305UW Short Fault
43PLUS, PLUS II, 1305VW Short Fault
441305IPM Current Fault
451305IPM Overtemp Fault
461305Power Test Fault (1305)
46PLUSPower Test Flt (1336 PLUS)
46PLUS IIDSP Protected (1336 PLUS II)
47PLUS, PLUS IIXsistr Desat Flt
48PLUS, PLUS II, 1305Reprogram Fault
49PLUS IIInput Phase Flt
50PLUS, PLUS IIPoles Calc Fault
55PLUS, PLUS IITemp Sense Open
56PLUS, PLUS IIPrecharge Open
57PLUS, PLUS IIGround Warning
58PLUS, PLUS IIBlwn Fuse Flt
60PLUS IIEncoder Loss
63PLUS, PLUS IIShear Pin Fault
64PLUS, PLUS IIPower Overload
66PLUS, PLUS IIEEprom Checksum

Each code: causes and first checks

Fault 02: Auxiliary Fault

Hits OEE: Availability

What it means: The auxiliary interlock input on the drive's control terminals is open, so the drive trips. It is one of the faults the drive is allowed to auto reset.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • An external interlock wired into the auxiliary input has opened
  • Loose or broken wiring at TB3 (TB3-24 on the 1336 PLUS) when the Control Interface option is fitted
  • [Input Mode] not set for a drive without the Control Interface option (Status on the PLUS II, 1 on the PLUS)

First checks, in this order

  1. Find which device in the auxiliary interlock circuit is open and correct it
  2. Check the TB3 wiring and terminals if the Control Interface option is installed
  3. If no Control Interface option is installed, set [Input Mode] as your manual says
  4. Clear the fault with Stop or a power cycle

Fault 03: Power Loss Fault

Hits OEE: Availability

What it means: The DC bus stayed under 85 percent of its normal level for more than half a second while line loss faulting was turned on. In plain terms, the incoming supply dipped or dropped out.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F3)

Likely causes

  • Low incoming AC line voltage
  • A line power interruption
  • [Line Loss Fault] enabled (F03 Enable on the 1305), so a dip trips the drive instead of riding through

First checks, in this order

  1. Measure the incoming AC voltage on all three phases
  2. Look for supply interruptions upstream of the drive at the time of the trip
  3. Confirm [Line Loss Fault] is set the way the process needs

Fault 04: Undervolt Fault

Hits OEE: Availability

What it means: The DC bus fell below the drive's minimum level. The 1336 manuals give 388 V DC as that minimum for a drive on a 460 V AC supply.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F4)

Likely causes

  • Low incoming AC line voltage
  • A line power interruption
  • Low bus faulting turned on ([Line Loss Fault] and [Low Bus Fault] enabled on the 1336, [Line Loss Fault] set to U Volt Run on the 1305)

First checks, in this order

  1. Measure the incoming AC voltage, ideally while the drive is loaded
  2. Look for supply interruptions or a weak supply
  3. Watch [DC Bus Voltage] (parameter 53) on the HIM while the drive runs

Fault 05: Overvolt Fault

Hits OEE: Availability

What it means: The DC bus voltage went above the drive's maximum. It comes from a high or spiky supply, or from the motor feeding energy back into the drive while it slows down.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F5)

Likely causes

  • High incoming line voltage
  • Transients on the AC line
  • Motor regeneration during deceleration
  • Decel time too short for the load

First checks, in this order

  1. Check the AC line for high voltage or transients
  2. Lengthen the decel time
  3. Install or check the dynamic brake option if the load has to stop quickly

Fault 06: Motor Stall Fault (1336 PLUS)

Hits OEE: Availability

What it means: Motor current stayed above 150 percent of [Rated Amps] for more than 4 seconds. The load is too heavy for the drive to bring the motor up to set speed.[2]

Also on: 1336 PLUS

Likely causes

  • Excessive load on the motor
  • Accel time too short for the load
  • Motor current held over 150 percent of rated amps

First checks, in this order

  1. Check the driven machine for anything that makes the load excessive
  2. Lengthen the accel time
  3. Reduce the load if the motor still cannot reach speed

Fault 06: Motor Stall Fault (1336 PLUS II)

Hits OEE: Availability

What it means: Current stayed above the [Current Limit] setting (parameter 36) for more than 4 seconds. The motor cannot accelerate to set speed with this load.[1]

Also on: 1336 PLUS II

Likely causes

  • Excessive load on the motor
  • Accel time too short for the load
  • [Current Limit] reached and held while accelerating

First checks, in this order

  1. Check the driven machine for anything that makes the load excessive
  2. Lengthen the accel time
  3. Reduce the load
  4. Review the [Current Limit] setting against the motor and machine

Fault 06: Motor Stall Fault (1305)

Hits OEE: Availability

What it means: The 1305 decided the motor is stalled. It is drawing too much current to accelerate to set speed.[3]

Also on: 1305 (shown as F6)

Likely causes

  • Excessive load on the motor
  • Accel time too short for the load

First checks, in this order

  1. Check the driven machine for anything that makes the load excessive
  2. Lengthen the accel time
  3. Reduce the load

Fault 07: Overload Fault

Hits OEE: Availability

What it means: The drive's built-in electronic motor overload tripped. Output current stayed above what the [Overload Amps] setting allows for too long.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Excessive motor load
  • Drive output current running above the [Overload Amps] setting

First checks, in this order

  1. Compare the running current with the [Overload Amps] setting
  2. Check the machine for extra load and reduce it
  3. Watch the Mtr Overload bit in [Drive Alarm] (parameter 60), which warns before the trip

Fault 07: Overload Fault (1305)

Hits OEE: Availability

What it means: The 1305's electronic motor overload tripped because output current stayed above the percentage set in [Overload Current].[3]

Also on: 1305 (shown as F7)

Likely causes

  • Excessive motor load
  • [Start Boost] set higher than needed
  • [Cable Length] not set to Long on a long motor cable

First checks, in this order

  1. Reduce the motor load
  2. Lower [Start Boost] if it has been raised
  3. Set [Cable Length] to Long if the motor cable is long

Fault 08: Overtemp Fault

Hits OEE: Availability

What it means: The heat sink got hotter than 90 C (195 F). The drive stops to protect its power parts.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Blocked or dirty heat sink fins
  • Ambient temperature above 40 C (104 F)
  • Cooling fan not working (listed in the PLUS II manual)

First checks, in this order

  1. Lock out power, then clean the heat sink fins
  2. Measure the air temperature around the drive
  3. Check that the cooling fan runs

Fault 08: Overtemp Fault (1305)

Hits OEE: Availability

What it means: The 1305's temperature sensor found too much heat in the drive.[3]

Also on: 1305 (shown as F8)

Likely causes

  • Blocked or dirty heat sink fins
  • Wrong mounting or too little space around the drive
  • Ambient temperature over the drive's limit

First checks, in this order

  1. Lock out power, then clean the heat sink fins
  2. Check mounting and spacing against the installation chapter
  3. Measure the air temperature around the drive

Fault 09: Open Pot Fault

Hits OEE: Availability

What it means: An external speed pot is connected and its common lead is open. The drive trips because an open pot lead could push the motor to overspeed.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F9)

Likely causes

  • Open common or ground lead on the external potentiometer
  • Broken wire or loose terminal in the pot circuit at TB2
  • More than 3.9 V DC across the pot leads (TB2-2 to TB2-3 on the 1336 PLUS)

First checks, in this order

  1. Check the pot circuit at TB2 terminals 1, 2 and 3 for an open circuit
  2. Check the potentiometer itself
  3. Retighten terminals and replace damaged cable

Fault 10: Serial Fault

Hits OEE: Availability

What it means: A SCANport device such as a HIM or communication adapter was disconnected while its [Logic Mask] bit was set to 1, so the drive treats the loss as a fault.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • SCANport adapter unplugged with its [Logic Mask] bit set to 1
  • Damaged SCANport wiring, expander or adapter
  • HIM not seated properly (PLUS II manual)
  • Main Control Board fault

First checks, in this order

  1. Check that the HIM and adapter cables are fully seated
  2. If an adapter was removed on purpose, set its [Logic Mask] bit to 0
  3. Replace wiring, expander or adapter if the fault repeats

Fault 10: Serial Fault (1305)

Hits OEE: Availability

What it means: A local bus adapter was disconnected while it had control of a drive function.[3]

Also on: 1305 (shown as F10)

Likely causes

  • Active adapter disconnected while in control
  • Break in the communications line

First checks, in this order

  1. Check the communications cable for a break or loose plug
  2. Reconnect the adapter, then clear the fault

Fault 11: Op Error Fault

Hits OEE: Availability

What it means: The drive received a request or a parameter combination it cannot carry out.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • A SCANport device asked to read or write a data type the drive does not support
  • [Motor Type] set to Sync PM with [Stop Mode Used] set to DC Brake
  • [Motor Type] set to Sync Reluc or Sync PM with [Speed Control] set to Slip Comp

First checks, in this order

  1. Check [Motor Type] against [Stop Mode Used] and [Speed Control]
  2. Check what the SCANport or PLC device is reading or writing

Fault 11: Op Error Fault (1305)

Hits OEE: Availability

What it means: DC braking is selected on a drive set up for a synchronous PM motor, which the 1305 does not allow.[3]

Also on: 1305 (shown as F11)

Likely causes

  • [Motor Type] set to Sync PM
  • [Stop Mode] set to DC Brake at the same time

First checks, in this order

  1. Confirm the real motor type and set [Motor Type] to match
  2. Choose a stop mode other than DC Brake if the motor is synchronous

Fault 12: Overcurrent Flt

Hits OEE: Availability

What it means: The hardware overcurrent trip circuit fired because output current jumped far above normal.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F12)

Likely causes

  • Short circuit at the drive output
  • Excessive load at the motor
  • Ground current above 220 percent of drive rated current, which the 1336 manuals say can show as Overcurrent instead of Ground Fault

First checks, in this order

  1. Lock out power and check the output cable and motor for a short circuit
  2. Check the machine for a sudden heavy load
  3. Check the output wiring and motor for a ground fault

Fault 13: Ground Fault

Hits OEE: Availability

What it means: More than 100 A is flowing to earth from one or more of the drive's output terminals.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Grounded motor winding
  • Grounded external wiring between the drive output terminals and the motor

First checks, in this order

  1. Lock out power and confirm the DC bus reads 0 V
  2. Disconnect the motor leads and test the motor and the cable to ground separately
  3. Repair the grounded part before restarting

Fault 15: Motor Thermistor

Hits OEE: Availability

What it means: An analog option board with a motor thermistor input reads a value outside its window, under 60 ohms or over 3300 ohms.[1]

Also on: 1336 PLUS II

Likely causes

  • Thermistor not connected
  • Motor overheated
  • Option board fitted on a motor that has no thermistor

First checks, in this order

  1. Check the thermistor wiring to the option board
  2. Check motor temperature and reduce the load if it runs hot
  3. If the motor has no thermistor, remove the option board as the manual says

Fault 17: C167 Watchdog

Hits OEE: Availability

What it means: Internal microprocessor fault on the drive's control electronics. The PLUS II manual handles 18 Hardware Trap, 27 DSP Comm Fault, 28 DSP Timeout Fault and 31 DSP Queue Fault the same way.[1]

Also on: 1336 PLUS II

Likely causes

  • Internal microprocessor fault
  • Main Control Board failure when the fault keeps returning

First checks, in this order

  1. If it happened once, reset the fault and carry on
  2. If it repeats often, call your service representative or replace the Main Control Board

Fault 19: Precharge Fault

Hits OEE: Availability

What it means: The DC bus precharge did not complete: the precharge device was still open 20 ms after a line loss ended, or the bus charging alarm stayed on for 20 seconds.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Faulty precharge circuit
  • Frames A1 to A3: precharge parts (the precharge NTC on the PLUS) or the whole drive
  • Frame B: precharge transistor or Power Driver Board
  • Larger frames: input SCRs, SCR Firing Board or Power Driver Board

First checks, in this order

  1. Find the drive's frame size in Chapter 1 of the manual
  2. Check the precharge circuit
  3. Replace the parts the manual lists for that frame, or the drive

Fault 20: Load Loss Flt

Hits OEE: Availability

What it means: Load loss detection is on and torque current stayed below [Load Loss Level] for longer than [Load Loss Time]. The motor is turning without its normal load.[1]

Also on: 1336 PLUS II

Likely causes

  • Mechanical connection between motor and load lost
  • [Load Loss Level] or [Load Loss Time] set too tight for the process

First checks, in this order

  1. Check the connection between motor and load, such as couplings and belts
  2. Check the level and time settings, or disable [Load Loss Detect] if it is not needed

Fault 22: Drive Reset Fault (Drive Fault Reset on 1336 PLUS, DSP Reset Fault on 1336 PLUS II, Drive Reset Flt on 1305)

Hits OEE: Availability

What it means: The drive was powered up with the stop contact open or the start contact closed (the 1305 manual names start closed with stop open). It is a control wiring or contact state problem at power up.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F22)

Likely causes

  • Start (or run) input held closed at power up
  • Stop input open at power up
  • [Run On Power Up] disabled while the start input is closed (1305 manual)

First checks, in this order

  1. Check the start and stop wiring and contacts
  2. On the 1305 check the stop connection at TB2 terminal 8
  3. Make sure the start contact is open before power is applied, then clear the fault

Fault 23: Loop Overrn Flt

Hits OEE: Availability

What it means: The drive's 2.5 ms internal control loop ran over its time.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Internal control timing overrun
  • Poor connections to the Power/Driver Board (1336 PLUS) or the Main Control Board (1336 PLUS II)

First checks, in this order

  1. Check and reseat all connections to the board your manual names
  2. Replace that board or the drive if the fault repeats

Fault 24: Motor Mode Flt

Hits OEE: Availability

What it means: An internal fault reported from the drive's control board.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F24)

Likely causes

  • Fault originating on the Control Board (1336)
  • Loose Control Board connections (1336)
  • Language Module problem (1336 PLUS manual)
  • Internal error (1305)

First checks, in this order

  1. On the 1305, reset the drive to factory defaults
  2. On the 1336, check all connections to the Control Board
  3. Replace the board or the drive if the fault repeats

Fault 26: Power Mode Fault

Hits OEE: Availability

What it means: An internal power mode value inside the drive received a wrong value.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F26)

Likely causes

  • Internal fault on the Control Board (1336)
  • Loose Control Board connections (1336)
  • Language Module problem (1336 PLUS manual)
  • Internal error (1305)

First checks, in this order

  1. On the 1305, reset the drive to factory defaults
  2. On the 1336, check all connections to the Control Board
  3. Replace the board or the drive if the fault repeats

Fault 29: Hertz Err Fault (Hz Err Fault on 1305)

Hits OEE: Availability

What it means: The drive cannot find a valid frequency to run at.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F29)

Likely causes

  • [Maximum Freq] set lower than [Minimum Freq]
  • Skip frequencies and the skip band cover every usable frequency
  • Analog or 4-20 mA speed reference lost with [4-20mA Loss Sel] set to Stop-Fault

First checks, in this order

  1. Check [Minimum Freq] and [Maximum Freq]
  2. Check [Skip Freq 1], [Skip Freq 2], [Skip Freq 3] and [Skip Freq Band]
  3. Check the analog input wiring for broken wires, loose connections or a failed transmitter

Fault 30: Hertz Sel Fault

Hits OEE: Availability

What it means: A frequency select parameter holds a value outside its allowed range.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Out of range value in [Freq Select 1] or [Freq Select 2]
  • Main Control Board fault if the problem stays after reprogramming

First checks, in this order

  1. Reprogram [Freq Select 1] and [Freq Select 2] with valid values
  2. Replace the Main Control Board or drive if it persists

Fault 30: Hz Sel Fault (1305)

Hits OEE: Availability

What it means: The active frequency source is an adapter that is not connected.[3]

Also on: 1305 (shown as F30)

Likely causes

  • Selected adapter not connected
  • Wrong active frequency source chosen

First checks, in this order

  1. Connect the proper adapter
  2. Or change the active frequency source to one that is present

Fault 32: EEprom Fault

Hits OEE: Availability

What it means: The drive's EEPROM is being programmed and will not accept a new value.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • EEPROM write blocked while programming is in progress
  • Loose wire or cable connections to the Main Control Board
  • Main Control Board fault

First checks, in this order

  1. Check all wire and cable connections to the Main Control Board
  2. Replace the Main Control Board or drive if it repeats

Fault 32: EEprom Fault (1305)

Hits OEE: Availability

What it means: The 1305's EEPROM holds invalid data or cannot be written with valid data.[3]

Also on: 1305 (shown as F32)

Likely causes

  • Invalid data in the EEPROM
  • Poor cable connection between the main control board and the power board

First checks, in this order

  1. Check the cable from the main control board to the power board
  2. Reset to default parameters and cycle power
  3. Re-enter the application's parameters

Fault 33: Max Retries Fault

Hits OEE: Availability

What it means: Auto restart tried the number of times set in [Reset/Run Tries] and the fault kept coming back, so the drive stays tripped.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F33)

Likely causes

  • A resettable fault keeps returning
  • The cause of the original fault has not been fixed

First checks, in this order

  1. Read the fault queue (1336) or [Fault Buffer 0] to [Fault Buffer 3] (1305) to find the original fault
  2. Fix the cause of that fault
  3. Clear manually: Stop key or TB3 stop input on the 1336, stop command or power cycle on the 1305

Fault 34: Run Boost Fault

Hits OEE: Availability

What it means: Someone tried to set [Run Boost] higher than [Start Boost], which the drive rejects.[2][3]

Also on: 1336 PLUS, 1305 (shown as F34). On the 1336 PLUS II, 34 is Prm Access Flt.

Likely causes

  • [Run Boost] value greater than [Start Boost]
  • Parameter programming error

First checks, in this order

  1. Compare [Run Boost] with [Start Boost]
  2. Set [Run Boost] no higher than [Start Boost], then clear the fault

Fault 34: Prm Access Flt (1336 PLUS II)

Hits OEE: Availability

What it means: A communication error happened between the drive's microprocessor and its serial EEPROM or DSP.[1]

Also on: 1336 PLUS II

Likely causes

  • Internal communication error with the serial EEPROM
  • Internal communication error with the DSP

First checks, in this order

  1. Write down the value in [Fault Data]
  2. Reset the fault
  3. Contact the factory if it happens again and again

Fault 35: Neg Slope Fault

Hits OEE: Availability

What it means: The volts per hertz curve programmed in the drive has a section that slopes downward, which the drive does not accept.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F35)

Likely causes

  • [Base Voltage] not greater than [Start Boost] (on the 1305 it must be more than 1.5 times [Start Boost])
  • With Full Custom (1336) or Break Point (1305) boost, [Break Voltage] not between [Start Boost] and [Base Voltage]
  • On 1336 PLUS firmware before 2.01, [Maximum Voltage] or [Maximum Freq] not above the base values

First checks, in this order

  1. Check [Base Voltage] against [Start Boost]
  2. Check [DC Boost Select] and, if custom, [Break Voltage]
  3. Correct the values so the curve only rises, then clear the fault

Fault 36: Diag C Lim Flt

Hits OEE: Availability

What it means: Output current hit the drive's hardware current limit while [Cur Lim Trip En] was enabled, so the drive tripped instead of just limiting.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Excess load
  • Wrong DC boost setting
  • DC brake volts set too high
  • [Cur Lim Trip En] enabled

First checks, in this order

  1. Check whether [Cur Lim Trip En] should be enabled for this machine
  2. Check the load
  3. Check DC boost and DC brake voltage settings

Fault 36: Diag C Lim Flt (1305)

Hits OEE: Availability

What it means: Output current went over the software [Current Limit] setting while [Cur Lim Trip En] was enabled.[3]

Also on: 1305 (shown as F36)

Likely causes

  • Excess load
  • Wrong DC boost setting
  • DC brake volts set too high
  • [Cur Lim Trip En] enabled

First checks, in this order

  1. Check whether [Cur Lim Trip En] should be enabled
  2. Check the load and the [Current Limit] setting
  3. Check DC boost and DC brake voltage settings

Fault 38: Phase U Fault

Hits OEE: Availability

What it means: The drive found a phase to ground fault on output phase U, somewhere between the drive and the motor.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F38)

Likely causes

  • Motor winding on that phase grounded
  • Motor cable on that phase damaged and touching ground

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Check the wiring between drive and motor on that phase
  3. Test the motor for a grounded phase

Fault 39: Phase V Fault

Hits OEE: Availability

What it means: The drive found a phase to ground fault on output phase V, somewhere between the drive and the motor.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F39)

Likely causes

  • Motor winding on that phase grounded
  • Motor cable on that phase damaged and touching ground

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Check the wiring between drive and motor on that phase
  3. Test the motor for a grounded phase

Fault 40: Phase W Fault

Hits OEE: Availability

What it means: The drive found a phase to ground fault on output phase W, somewhere between the drive and the motor.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F40)

Likely causes

  • Motor winding on that phase grounded
  • Motor cable on that phase damaged and touching ground

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Check the wiring between drive and motor on that phase
  3. Test the motor for a grounded phase

Fault 41: UV Short Fault

Hits OEE: Availability

What it means: Too much current is flowing between output terminals U and V, which points to a short between those two phases.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F41)

Likely causes

  • Short between the U and V motor leads
  • Shorted motor winding

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Check the external wiring from the drive output terminals for a short
  3. Test the motor windings

Fault 42: UW Short Fault

Hits OEE: Availability

What it means: Too much current is flowing between output terminals U and W, which points to a short between those two phases.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F42)

Likely causes

  • Short between the U and W motor leads
  • Shorted motor winding

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Check the external wiring from the drive output terminals for a short
  3. Test the motor windings

Fault 43: VW Short Fault

Hits OEE: Availability

What it means: Too much current is flowing between output terminals V and W, which points to a short between those two phases.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F43)

Likely causes

  • Short between the V and W motor leads
  • Shorted motor winding

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Check the external wiring from the drive output terminals for a short
  3. Test the motor windings

Fault 44: IPM Current Fault

Hits OEE: Availability

What it means: The overcurrent limit of the 1305's internal power module was exceeded.[3]

Also on: 1305 (shown as F44)

Likely causes

  • Short circuit at the drive output
  • Excessive load at the motor
  • Motor cable capacitance to ground

First checks, in this order

  1. Lock out power and check the output wiring and motor for a short
  2. Check the motor load
  3. Check the motor cable run, since cable capacitance to ground is named in the manual

Fault 45: IPM Overtemp Fault

Hits OEE: Availability

What it means: The 1305's internal power module went past its thermal limit.[3]

Also on: 1305 (shown as F45)

Likely causes

  • Blocked or dirty heat sink fins
  • Wrong mounting or too little space around the drive
  • Ambient temperature over the limit

First checks, in this order

  1. Lock out power, then clean the heat sink fins
  2. Check mounting and spacing
  3. Measure the air temperature around the drive

Fault 46: Power Test Fault (1305)

Hits OEE: Availability

What it means: The 1305 found a problem during its start-up test sequence.[3]

Also on: 1305 (shown as F46)

Likely causes

  • Drive wiring problem
  • Motor wiring problem

First checks, in this order

  1. Check the drive wiring
  2. Check the motor wiring
  3. Reset the drive to factory defaults

Fault 46: Power Test Flt (1336 PLUS)

Hits OEE: Availability

What it means: An internal power mode value in the 1336 PLUS received a wrong value.[2]

Also on: 1336 PLUS

Likely causes

  • Internal drive fault
  • Poor connections to the Power/Driver Board

First checks, in this order

  1. Check all connections to the Power/Driver Board
  2. Replace the board or the drive if it repeats

Fault 46: DSP Protected (1336 PLUS II)

Hits OEE: Availability

What it means: A flash firmware download included a new DSP main block, but jumper J14 was not fitted when power came back.[1]

Also on: 1336 PLUS II

Likely causes

  • Flash download that contains a new DSP main block
  • Jumper J14 not installed at power up

First checks, in this order

  1. Remove power from the drive
  2. Install J14 as the download kit instructions say and reapply power
  3. When the transfer is complete, remove power and take J14 out

Fault 47: Xsistr Desat Flt

Hits OEE: Availability

What it means: On frame C and larger drives, one or more output transistors ran in their active region instead of fully switched on. Too much transistor current or too little base drive voltage causes it.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Excessive transistor current
  • Insufficient base drive voltage
  • Damaged output transistors

First checks, in this order

  1. Lock out power and check for damaged output transistors
  2. Replace the output transistors, Power Driver Board or drive as needed

Fault 48: Reprogram Fault

Hits OEE: Availability

What it means: The drive was told to write factory default values into its EEPROM, and it flags this as a fault.[1][2][3]

Also on: 1336 PLUS, 1336 PLUS II, 1305 (shown as F48)

Likely causes

  • Reset to defaults run from the HIM's EEPROM mode
  • [Set Defaults] parameter used (the 1305 manual notes this leaves F48 in [Fault Buffer 0])

First checks, in this order

  1. Clear the fault or cycle power
  2. Program the application's parameters again
  3. On the 1336, cycle power if [Input Mode] was changed so the new value takes effect

Fault 49: Input Phase Flt

Hits OEE: Availability

What it means: DC bus ripple went above the [Phase Loss Level] setting, which points to a missing input phase.[1]

Also on: 1336 PLUS II

Likely causes

  • Missing input phase
  • Blown input fuse
  • Single-phase supply with the load above the derating level

First checks, in this order

  1. Measure all three incoming phases
  2. Check the input fuses
  3. If the drive runs on single-phase, reduce the load to the derated level

Fault 50: Poles Calc Fault

Hits OEE: Availability

What it means: The motor pole count the drive calculates from the nameplate data came out below 2 or above 32.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Wrong value in [Motor NP RPM]
  • Wrong value in [Motor NP Hertz]

First checks, in this order

  1. Compare [Motor NP RPM] and [Motor NP Hertz] with the motor nameplate
  2. Correct them and clear the fault

Fault 55: Temp Sense Open

Hits OEE: Availability

What it means: The heat sink thermistor is open or not working, so the drive cannot read its own temperature.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Open heat sink thermistor
  • Loose or broken thermistor connection

First checks, in this order

  1. Lock out power and check the thermistor connections
  2. Check the thermistor itself

Fault 56: Precharge Open

Hits OEE: Availability

What it means: The drive told the precharge circuit to close, but it still reads open.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Faulty precharge circuit
  • Frames A1 to A3: precharge parts or the whole drive
  • Frame B: precharge transistor or Power Driver Board
  • Larger frames: input SCRs, SCR Firing Board or Power Driver Board

First checks, in this order

  1. Find the drive's frame size in the manual
  2. Check the precharge circuit
  3. Replace the parts the manual lists for that frame, or the drive

Fault 57: Ground Warning

Hits OEE: Availability

What it means: More than 2 A is flowing to earth at one or more output terminals. It only trips the drive when the [Ground Warning] parameter (204) is enabled, and that is off from the factory.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Grounded motor winding
  • Grounded external wiring at the drive output

First checks, in this order

  1. Lock out power and test the motor and output cable to ground
  2. Inspect the output wiring for damaged insulation
  3. Keep an eye on the Ground Warning alarm bit in parameter 60 ([Drive Alarm] on the PLUS, [Drive Alarm 1] on the PLUS II)

Fault 58: Blwn Fuse Flt

Hits OEE: Availability

What it means: On 30 kW (40 HP) and larger drives, commanded and measured voltage differed by more than one eighth of rated voltage for 0.5 seconds, which the drive reads as a blown DC bus fuse.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Blown DC bus fuse
  • Whatever fault made the fuse blow

First checks, in this order

  1. Lock out power and confirm the DC bus is discharged
  2. Find the cause before replacing anything
  3. Replace the bus fuse

Fault 60: Encoder Loss

Hits OEE: Availability

What it means: The drive found an error in the encoder signals at TB3 terminals 31 to 36.[1]

Also on: 1336 PLUS II

Likely causes

  • Loss of one or more encoder channels
  • Loss of quadrature
  • Loss of the differential signal (A and A NOT, or B and B NOT, high at the same time)

First checks, in this order

  1. Check the encoder wiring at TB3 terminals 31 to 36
  2. Check the encoder itself

Fault 63: Shear Pin Fault

Hits OEE: Availability

What it means: Current went above the [Current Limit] setting while [Shear Pin Fault] was enabled, so the drive trips at once instead of riding through.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Load demanding more than the [Current Limit] setting
  • [Current Limit] set lower than the machine needs

First checks, in this order

  1. Check what the machine needs against the [Current Limit] setting
  2. Check the machine for a jam or extra load

Fault 64: Power Overload

Hits OEE: Availability

What it means: The drive itself was pushed past its rating of 150 percent for 1 minute. This protects the drive, not the motor.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Motor load above what the drive is rated for
  • Drive held above 150 percent of its rating for more than 1 minute

First checks, in this order

  1. Reduce the load
  2. Check that the drive size matches the duty of the machine

Fault 66: EEprom Checksum

Hits OEE: Availability

What it means: The checksum read from the EEPROM does not match the one calculated from the stored data, so the saved parameters cannot be trusted.[1][2]

Also on: 1336 PLUS, 1336 PLUS II

Likely causes

  • Corrupt EEPROM data
  • Loose wire or cable connections to the Power Driver Board
  • Power Driver Board fault

First checks, in this order

  1. Reset to factory defaults and cycle input power
  2. Check all wire and cable connections to the Power Driver Board
  3. Replace the Power Driver Board or drive if it repeats

Log it, or the same alarm comes back

An old drive that faults stops the motor and the machine with it, so in OEE terms it is a breakdown, and the minutes it costs are the best argument for planning its replacement. Log the fault code, the drive and the minutes lost.

  • Reason code: the code plus the drive, for example 1336 PLUS fault 07, mixer motor, so an overload that trips every summer afternoon stands out.
  • Loss bucket: a stop that needs a reset, a part or a technician is an availability loss (breakdown). Stops shorter than your micro-stop threshold go to performance (minor stops). The six big losses page shows where each one belongs.
  • What to count: how often each code fires per week and the minutes it costs. Two numbers a week turn "that alarm comes up sometimes" into a ranked list. The MTBF and MTTR calculator and the downtime cost calculator do the math.

The free OEE tracker logs each stop with its reason and turns the week into a downtime Pareto, so the code that costs the most rises to the top.

For drive faults across brands, fabrico.io has a VFD fault codes guide. A fault code tells you what the drive measured, not what happened at the machine in the seconds before. Fabrico's camera-based OEE software syncs line camera video with machine data, so you can replay the moment the line stopped next to the trip.

Frequently asked questions

How do I reset a fault on an Allen-Bradley 1336 PLUS II?

Fix the cause first, because the drive will trip again if it is still there. Then cycle drive power, or press Stop on the HIM or open the TB3 stop input, which clears the fault when [Flt Clear Mode] (parameter 39) is Enabled, the factory setting. A Clear Faults command from a serial device also works.

What is the difference between 07 Overload Fault and 64 Power Overload on a 1336 PLUS or PLUS II?

07 is the motor overload: the drive's electronic overload tripped because output current stayed above the [Overload Amps] setting. 64 protects the drive itself and trips when the drive has run above 150 percent of its own rating for more than 1 minute. Both point to too much load, but 07 can be auto reset and 64 cannot.

Why does my 1305 show F22 Drive Reset Fault when I switch it on?

The 1305 saw its start (or run) input closed and its stop input open at power up while [Run On Power Up] was disabled. Check the stop wiring at TB2 terminal 8 and make sure the start contact is open when power comes on, then clear the fault.

Can a 1336 PLUS, 1336 PLUS II or 1305 restart itself after a fault?

Yes, for the faults the manual lists as resettable, such as 03 Power Loss, 05 Overvolt and 12 Overcurrent. Set [Reset/Run Tries] (parameter 85) to the number of attempts and [Reset/Run Time] (parameter 15) to the wait between them. If the fault keeps returning after those tries, the drive trips on 33 Max Retries Fault and needs a manual clear, and on the 1305 the try counter goes back to zero after 4 minutes without a fault.

Do the 1336 IMPACT and 1336 FORCE use these same fault numbers?

The 1336 IMPACT uses its own scheme: its user manual (publication 1336 IMPACT-5.0) lists five digit codes such as 12016 Overvoltage, 12018 Ground Fault and 12019 Overcurrent. The two digit numbers on this page come from the 1336 PLUS, 1336 PLUS II and 1305 manuals, so look up IMPACT and FORCE faults in those drives' own manuals.

Sources

Codes and meanings follow the manufacturer documentation below. Wording is ours, simplified for the shop floor; the manual for your exact model and software version wins if it differs.

  1. 1336 PLUS II Adjustable Frequency AC Drive with 0.37-448 kW (0.5 - 600 HP), Firmware 1.xxx - 6.xxx, User Manual, Publication 1336 PLUS-5.3
  2. 1336 PLUS Adjustable Frequency AC Drive with 0.37-448 kW (0.5 - 600 HP), FRN 1.xx - 5.xx, User Manual, Publication 1336 PLUS-5.0
  3. 1305 Adjustable Frequency AC Drive (Series C) 0.37...4 kW (0.5...5 Hp), Firmware 6.01 and Up, User Manual, Publication 1305-5.2

See the moment the drive tripped

Fabrico, a light MES with computer vision, syncs camera footage with machine and timeline data, so you can replay the exact moment the line stopped and review the cause next to the drive's fault. Cameras also catch short stops and a line that is switched on but not producing, the losses nobody writes down. Machines connect through a PLC, a Fabrico IoT device or an AI camera.

Book a Fabrico demo
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OEE essentials: OEE calculator · What is OEE · How to improve OEE · Six big losses · Availability · TEEP · Cost of downtime · OEE benchmark · Free OEE tracker · Free OEE software · How to track downtime · How to implement OEE · Light MES vs full MES