FAULT: CHOPPER RUNNING

Chopper is currently in operation. This is a status indicator.

FAULT: NO COMMUNICATION

Communication failure between MDI console and controller.

Possible Causes:

Logic board failure.

Driver breakdown from overvoltage in contactor wiring

Driver voltage inconsistent with preset value.

Solutions:

Identify and remove cause of overvoltage.

Check contactor negative wiring for damage.

Replace logic board after removing cause.

FAULT: UNKNOWN CHOPPER

Console does not recognize the chopper model or configuration.

Possible Causes:

Chopper not configured via console.

Configuration data corrupted in EEPROM.

Incompatible console/chopper combination.

Solutions:

Access "SEL MODEL" menu and configure chopper type.

Set options via "SEL OPTIONS" menu.

Configure battery voltage via "SEL BATTERY" menu.

If configuration cannot be saved, check AL 12-14.

FAULT: CONSOLE EEPROM

Console memory error. Configuration may be lost.

Solutions:

Cycle power to console

Reconfigure if settings lost

Replace console if error persists.

FAULT: SERIAL ERROR 2 / SERIAL ERROR 1

Serial communication errors between components.

Solutions:

Check all serial cable connections.

Ensure cables are not damaged or pinched.

Keep serial cables away from high current power cables.

Replace faulty cables.

FAULT: CHOPPER NOT CONFIG

Chopper configuration incomplete or invalid. Similar to AL 03.

Solutions:

Connect programming console.

Configure model type (regenerative/standard traction or pump).

Set all required options.

Verify configuration is saved to EEPROM.

FAULT: WATCHDOG

LED Pattern: 1 blink. Microprocessor self-diagnosis failure - logic unit malfunction.

Test: Performed in both standby and running modes.

Possible Causes:

Logic board processor failure.

Software crash or corruption.

Power supply instability to logic.

Solutions:

Switch machine off and on to reset.

Check 12V supply to logic board.

If alarm persists after restart, replace logic board immediately.

Do not operate machine with persistent watchdog error.

FAULT: FIELD FF FAILURE

Field weakening circuit failure.

Possible Causes:

Weakening contactor failure.

Field circuit wiring fault.

Logic board field control circuit fault.

Solutions:

Check weakening contactor (G3 connector) operation.

Verify field wiring connections to motor.

Test contactor coil resistance.

Replace faulty contactor or logic board

FAULT: EEPROM DATA KO

LED Pattern: 1 blink. Hour-meter data area corrupted in non-volatile memory.

Note: This alarm does NOT shut down the machine.

Solutions:

Cycle power (key off/on).

If alarm disappears: hour-meter has been reset to zero - normal operation can continue.

If alarm persists: replace logic board.

Record current hour-meter value before replacement.

FAULT: EEPROM PAR KO

LED Pattern: 1 blink. Adjustment parameters memory corrupted. This alarm INHIBITS machine operation.

Solutions:

Cycle power (key off/on).

If alarm disappears: all parameters reset to defaults - reprogram via console.

Use console "RESTORE" function if parameters were previously saved.

If alarm persists: replace logic board.

After clearing: recalibrate all parameters per section 5.3 or 6.3.

FAULT: EEPROM CONF KO

LED Pattern: 

1 blink. Configuration data memory fault.

Solutions:

Cycle power (key off/on).

If alarm clears: configuration reset to defaults - must reconfigure:

  • Select model type (SEL MODEL menu)

  • Configure options (SEL OPTIONS menu)

  • Set battery voltage (SEL BATTERY menu)

If alarm persists: replace logic board then reconfigure.

FAULT: EEPROM KO

LED Pattern: 

1 blink. General EEPROM failure.

Solutions:

Cycle power.

If persists: replace logic board.

Reconfigure and reprogram after replacement.

FAULT: EEPROM OFFLINE

LED Pattern: 

1 blink. Non-volatile memory not responding.

Solutions:

Cycle power.

Check logic board connections.

If alarm persists: replace logic board.

Note: Hour-meter, alarm history, and parameters will be lost.

FAILURE: LOGIC FAILURE 5-1

LED Pattern: 

1 blink. Internal logic circuit failures.

Solutions:

Cycle power to reset processor.

Check for loose connections on logic board.

Verify proper voltage supply to logic.

If alarm persists: replace logic board.

Different numbers indicate different internal circuit faults.

FAULT: VMN LOW/HIGH (DIRECTION SPECIFIC)

Motor negative voltage (VMN) out of range for specific direction (Forward/Back/Left/Right/Pump).

Possible Causes:

Motor wiring error for specific direction.

Direction contactor failure.

Poor connections in motor circuit.

Solutions:

Verify motor connections for the indicated direction.

Check specific direction contactor operation.

Test motor in problem direction under no load.

Inspect all cable connections for corrosion or looseness.

FAULT: VMN LOW

LED Pattern: 3 blinks. Motor negative voltage below 1/3 battery voltage in standby or running (up to 80% PWM).

Diagnosis Procedure:

1. At key on: Disconnect motor cable from battery

  • If alarm persists → Logic failure (solution C5)

  • If alarm clears → Check contactors

2. Running with contactors on: → Logic failure (C5)

3. During release braking: If bypass/weakening present → Check contactor (E1)

Possible Causes:

B7/B8: Running contactor stuck - coil supplied or wire shorted to negative.

D1: Motor cables crossed (stator/armature reversed).

D2: Current leakage in motor between windings.

D3: Short to negative on SH- or SH+ connection points.

E1: Bypass/weakening contactor stuck or slow opening.

C5: Controller internal failure

Solutions:

For B7: Disconnect contactor wire from board - if contactor stays on, replace logic.

For B8: Unlock and replace stuck contactor.

For D1: Correct motor cable connections.

For D2: Test motor insulation - replace motor if leakage found.

For D3: Remove metallic debris from contactor board area.

For E1: Disconnect bypass contactor - if fault clears, replace logic. WARNING: Contactors must not have external arc suppressors

For C5: Replace controller

FAULT: VMN HIGH

LED Pattern: 8 blinks. VMN voltage greater than 2/3 battery voltage in standby.

Possible Causes:

Contactor stuck closed (standard traction only).

Short circuit between +BATT and VMN.

Logic failure - braking diodes damaged.

Solutions:

Check for metallic parts causing short in contactor board.

Verify all contactors open in standby.

Replace power unit if braking diodes failed.

Replace stuck contactors.

FAULT: VMN NOT OK

General VMN circuit fault.

Solutions:

Check VMN power connector for proper connection.

Verify motor wiring is correct.

Test in both standby and running conditions.

Replace controller if internal VMN sensing circuit failed.

FAULT: NO FULL COND / NO FULL CONDUCTION

LED Pattern: 3 blinks. In full conduction, VMN > 1/3 VBATT. Diagnostic circuit faulty - INHIBITS OPERATION.

Possible Causes:

Logic board diagnostic circuit failure.

Power unit sensing circuit fault.

Poor connection between logic and power.

Solutions:

If fault persists: replace logic board immediately.

Check connector between logic and power unit.

This is a safety-critical fault - do not bypass.

FAULT: RGT/LFT/PU NO FULL COND

Full conduction not achieved for Right/Left/Pump motor.

Solutions:

Similar to AL 33 but specific to one motor.

Check wiring for the specific motor indicated.

Verify contactor operation for that circuit.

Replace logic if fault persists.

FAULT: CONTACTOR CLOSED

Contactor stuck closed when it should be open.

Solutions:

Identify which contactor is stuck.

Clean contactor contacts with compressed air.

Check for dirt or particles preventing proper operation.

Replace contactor if mechanically damaged.

FAULT: CONTACTOR OPEN

LED Pattern: 

2 or 8 blinks. Contactor fails to close when commanded.

Diagnosis Chart:

Forward only:

  • Forward contactor (TA) closes 0.3s then opens? YES → A1

  • Voltage at coil for 0.3s? YES → B1, NO → C1

Backward only:

  • Backward contactor (TI) closes 0.3s then opens? YES → A2

  • Voltage at coil for 0.3s? YES → B2, NO → C2

Both directions:

  • Either contactor closes 0.3s then opens? YES → A3

  • Voltage at coils? YES → B3, NO → C3

Solutions by Diagnosis Code:

A1/A2: Poor contact on TA/TI due to dust - clean with compressed air, soft abrasive if needed. May need to replace both contactors.

A3: Brake contactor NC contact poor or doesn't reach battery negative. May need to replace. Also check for: brush lift from collector, brush cable burned, missing brake contactor negative cable, motor winding interruption.

B1/B2/B3: Contactor supplied but doesn't close: 1) Coil interrupted (check with ohmmeter), 2) Mechanical block, 3) Nominal voltage > battery voltage.

C1/C2/C3: No supply to contactor - check wiring from coil to PT/NTA/NTI connectors. May need to replace controller.

FAULT: BRAKE DON'T CLOSED

Brake contactor fails to close (regenerative models only).

Test: During passage to running. After running contactor closure, brake contactor should close and VMN should go from <1/3 to >2/3 VBATT.

Solutions:

A4: No good contact on TFR NA - clean or replace contactor.

A5: Missing positive cable on brake contactor.

B4: Coil interrupted (check with ohmmeter) - replace contactor.

B5: Contactor mechanically locked - unlock and replace.

B6: Contactor nominal voltage too high for battery.

C4: No supply to coil - check wiring to C1(PTFR) and C5(NTFR).

FAULT: BRAKE CONT OPEN

LED Pattern: 8 blinks (regenerative). Brake contactor won't open. Test during passage to running.

Solutions:

Check if brake contactor NA stuck closed - clean contacts.

Test if contactor stays energized with NTFR disconnected.

If energized without board connection: wire shorted to negative.

If energized with board: replace logic board

FAULT: DIR CONT CLOSED

LED Pattern: 

9 blinks (regenerative only). Direction contactor stuck closed. Test during passage to standby/braking.

Solutions:

Direction contactor stuck or slow to open.

Clean or replace contactor.

Logic failure - replace if contactor is good.

FAULT: DIR CONT OPEN

Direction contactor fails to close - see detailed procedure for AL 38.

FAULT: RIGHT/LEFT/MAIN CONT CLOSED/OPEN

Specific contactor (Right, Left, or Main) stuck closed or won't open/close.

Solutions:

Follow same diagnostic procedures as AL 37-42.

Focus on the specific contactor indicated.

Check wiring to that contactor's coil connections.

Clean or replace affected contactor.

FAULT: I=0 EVER

LED Pattern:

 5 blinks. No current detected during running. Machine shuts down.

Test: 

During running - checks current is above minimum value.

Possible Causes:

Current sensor faulty.

Wrong motor cable connections to SH- and SH+.

Motor circuit open.

Solutions:

Verify motor cables connected to correct SH terminals.

Check motor brush contact.

Test motor continuity.

Replace power unit (current sensor failure).

FAULT: LEFT/RIGHT/PUMP I=0 EVER

No current detected in specific motor (Left/Right/Pump).

Solutions:

Same as AL 49 but for specific motor.

Check connections for indicated motor only.

Verify that motor is operational.

FAULT: STBY I HIGH

LED Pattern: 5 blinks. Current detected in standby when it should be zero. Inhibits operation.

Test: In standby - verifies current is nil.

Possible Causes:

Current sensor broken.

Logic board failure.

Solutions:

Replace logic board first.

If fault persists, replace power unit.

FAULT: LEFT/RGT/PUMP STBY I HIGH

Standby current high for specific motor.

Solutions:

Same as AL 53 for specific motor circuit.

FAULT: HIGH FIELD CURR

Excessive field current detected.

Solutions:

Check field winding for short circuit.

Verify weakening contactor operation.

Inspect field connections for damage.

Replace motor if field winding shorted.

FAULT: NO FIELD CURR

No field current when expected.

Solutions:

Check field winding continuity.

Verify field connections not loose or corroded.

Check for broken field wires.

Replace motor if field winding open.

FAULT: HIGH BRAKING I

Braking current exceeds safe limits.

Solutions:

Reduce braking parameters (INVERSION BRAKING, PEDAL BRAKING).

Check for motor overload condition.

Verify battery voltage is within spec.

Consider using "soft braking" option.

FAULT: CAPACITOR CHARGE

Internal capacitor charge issue.

Solutions:

Allow capacitors to fully discharge (wait 5 minutes with key off).

Check battery voltage is within specification.

If persistent, replace power unit.

FAULT: HIGH TEMPERATURE

LED Pattern: 

7 blinks. Controller temperature exceeded 80°C. Max current gradually reduced, reaching 0 at 85°C.

Possible Causes:

Inadequate heat dissipation.

Poor mounting/thermal contact.

Excessive duty cycle.

Thermal sensor failure (if cold).

Solutions:

If occurs while cold: Check thermal sensor connection, replace power or logic board.

If occurs during operation:

  • Check mounting nuts are tight.

  • Verify thermo-conductive grease applied.

  • Ensure adequate ventilation in compartment.

  • Consider forced air cooling.

  • Reduce duty cycle or upgrade to higher capacity model.

• Allow controller to cool before resuming operation.

FAULT: TH PROTECTION

Thermal protection activated - same as AL 61.

FAULT: THERMIC LEVEL 2

Temperature warning - approaching thermal limit.

Solutions:

Reduce load or allow cooling period.

Check cooling as per AL 61.

FAULT: PUMP/MOTOR TEMPERATURE

Specific motor overheating.

Solutions:

Allow motor to cool.

Check motor ventilation.

Verify motor not overloaded.

Check motor bearings for excessive friction.

FAULT: BATTERY LOW

LED Pattern: 

Continuous blinking (32 blinks). Battery charge <10%. Max current reduced to 50%.

Note: 

Only active if "BATTERY CHECK" option selected.

Solutions:

Recharge battery immediately.

Check battery condition and connections.

Verify battery voltage setting in controller matches actual battery.

Test individual cell voltages.

Replace battery if degraded.

FAULT: BATTERY LEVEL 2

Battery charge level 2 warning.

Solutions:

Plan to recharge soon.

Similar actions as AL 66.

FAULT: BATTERY LEVEL 1

Critical battery level - immediate recharge required. In lifting configuration, all functions blocked except hydrodrive.

FAULT: CURRENT SENS KO

Current sensor malfunction.

Solutions:

Check sensor connections (SH- and SH+).

Replace power unit.

FAULT: POWER FAILURE 4-1

Power stage failures - various severity levels.

Solutions:

Check power connections (+B, -B, VMN).

Verify battery voltage within specification.

Check for short circuits in power wiring.

Replace power unit if internal failure.

FAULT: DRIVER SHORTED

LED Pattern: 

6 blinks. Contactor driver output shorted. Test in standby.

FAULT: DRIVER CONTACTOR

Contactor driver circuit malfunction.

Solutions:

Same as AL 74.

Check specific contactor driver circuit.

FAULT: COIL SHORTED

LED Pattern: 

6 blinks. Overload or short circuit on contactor negative driver outputs.

Possible Causes:

Contactor coils short circuited.

Coils absorb more than 6A continuous.

Short circuit with +BATT in wiring from contactor connector.

Solutions:

Test each contactor coil resistance with ohmmeter.

Check coil current draw (should be <3A per spec).

Inspect wiring for shorts to positive.

Replace faulty contactor(s).

Note: This indicates overload occurred, not chopper component breakdown. Once external cause removed, chopper can restart.

FAULT: COIL INTERRUPTED

Contactor coil circuit interrupted.

Solutions:

Check all contactor coil connections.

Test coil continuity with ohmmeter.

Inspect wiring for breaks.

Replace contactor with interrupted coil.

FAULT: VACC NOT OK

LED Pattern: 

4 blinks. Accelerator voltage >1V above stored minimum in standby. Inhibits operation.

Test: Made in standby.

Possible Causes:

Potentiometer wire interrupted.

Potentiometer negative not connected to PIN C2.

Potentiometer not correctly calibrated.

Potentiometer defective.

Solutions:

Check all three potentiometer wires (C1, C2, C3).

Verify C2 connected to battery negative.

Verify C3 has 12V output (don't short to negative).

Perform potentiometer signal acquisition via "PROGRAM VACC" menu.

Test potentiometer with ohmmeter (should be 500Ω to 10kΩ).

Replace potentiometer if defective.

FAULT: INCORRECT START

LED Pattern: 

2 blinks. Incorrect starting sequence - running request present at startup.

Possible Causes:

Running microswitch stuck.

Handle microswitch stuck.

Operator error - pedal pressed at key on.

Incorrect wiring.

Solutions:

Ensure correct sequence: key → handle/seat → running request.

Release all controls before switching key on.

Test microswitches for sticking.

Check microswitch wiring.

If no external defects found, replace logic.

FAULT: FORW+BACK

LED Pattern: 

LED remains ON continuously. Two running requests made simultaneously.

Test: 

Continuous monitoring.

Possible Causes:

Defective wiring.

Running microswitch stuck.

Incorrect operator manoeuvre.

Logic failure.

Solutions:

Check forward microswitch (E7/MA) operation.

Check backward microswitch (E6/MI) operation.

Verify microswitches release properly.

Inspect wiring for shorts between direction signals.

If no external defects, replace logic.

FAULT: TRACTION/PUMP/STEER MOTOR TEMPERATURE

Specific motor overheating.

Solutions:

Allow motor to cool down.

Check motor is not overloaded.

Verify motor ventilation adequate.

Check motor bearings.

Inspect motor brushes for excessive wear.

FAULT: STEER SENSOR NOT OK

Steering sensor malfunction.

Solutions:

Check steering sensor connections.

Verify sensor power supply.

Test sensor output signal.

Replace sensor if faulty.

FAULT: STEER HAZARD

Steering system safety hazard detected.

Solutions:

Immediately stop machine operation.

Check steering system mechanically.

Verify steering sensor operation.

Check steering motor operation.

Inspect steering linkages.

FAULT: PEDAL WIRE KO

Pedal wiring fault detected.

Solutions:

Inspect pedal potentiometer wiring.

Check for broken or damaged wires.

Verify connections at pedal and controller.

Test potentiometer continuity.

Replace damaged wiring or potentiometer.

FAULT: PEDAL FAILURE

Pedal system malfunction.

Solutions:

Check pedal microswitches operation.

Test pedal potentiometer.

Verify pedal mechanical operation.

Check pedal return spring.

Replace faulty pedal components.

RESERVED:

Reserved for future use. Not currently assigned.

FAULT: TRACTION MOTOR BRUSHES

Traction motor brushes worn - replacement required soon.

Solutions:

Inspect motor brushes for wear.

Measure brush length.

Replace brushes if below minimum length.

Check brush springs for proper tension.

Clean commutator if necessary.

Preventive: Schedule brush replacement.

FAULT: PUMP MOTOR BRUSHES

Pump motor brushes worn - replacement required soon.

Solutions:

Same procedure as AL 91 for pump motor

FAULT: STEER MOTOR BRUSHES

Steering motor brushes worn - replacement required soon.

Solutions:

Same procedure as AL 91 for steering motor

FAULT: INPUT ERROR 6

Input signal error on pin E6.

Solutions:

Check E6 input wiring.

Verify signal levels at E6 (function depends on configuration).

Test associated microswitch or sensor.

Check for shorts or opens in wiring.

FAULT: INPUT ERROR 5

Input signal error on pin E5.

Solutions:

Check E5 input wiring.

E5 typically brake pedal input - test microswitch.

Verify signal transitions properly.

FAULT: INVERSION

Direction inversion error.

Solutions:

Check forward/backward microswitches.

Verify proper inversion sequence.

Check if Quick Inversion option configured correctly.

Test E1 input if Quick I configured.

FAULT: HANDLE POSITION

Handle position sensor error.

Solutions:

Check handle microswitch (E4) operation.

Verify handle returns to neutral position.

Check mechanical linkage.

Test microswitch with multimeter.

Verify E4 configured correctly (seat vs handle).

FAULT: INPUT ERROR 2

Input signal error on pin E2.

Solutions:

Check E2 input wiring.

E2 is RV2 (speed reduction 2) or BACKING.

Test associated microswitch.

Verify correct option configured in SEL OPTIONS.

FAULT: INPUT ERROR 1

Input signal error on pin E1.

Solutions:

Check E1 input wiring.

E1 is RV3 (speed reduction 3) or QUICK I.

Test associated microswitch.

Verify correct option configured (Cut b.#3 vs Quick I).

If Quick I: check safety button operation.