Yale and Hyster Pallet Jack Error Codes

Error Codes for Hyster W40Z or Yale MPB40-E Pallet Jack

 

Error: No LEDs or LCDs on

What the issue is: Inoperative
Cause of Problem: B+ and/or B- missing at the controller, defective battery, or defective battery charger
What to do: Ensure the battery is connected, the key switch is on, and the brake override circuit is in the run position. Test the battery charger and motor controller, and replace any non-working parts

Error: No LEDs or LCDs on

What the issue is: Forklift functions as normal
Cause of Problem: Open connection between display and controller, defective display, or defective LEDs
What to do: Ensure harnesses are connected at MDI and connector B on the controller. Test the dash display by connecting a handset to check for communication. Test LEDs by disconnecting them, connecting the handset, and performing the test. Replace any faulty parts

Error: No LEDs or LCDs on

What the issue is: Forklift functions as normal
Cause of Problem: Similar to the previous issue, but requires a handset to diagnose. If the handset shows “NO COMMUNICATION,” the controller is defective.
What to do: Replace the controller

Error: No Alarm

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Improper startup sequence by the operator
What to do: Check the brake switch, accelerator, steer handle, and hydraulic inputs

Error: AL66

What the issue is: Hydraulic function not working
Cause of Problem: Low battery voltage or incorrect controller voltage calibration
What to do: Charge or replace the battery. Use a handset to check the voltage reading from the controller and compare it to a voltmeter. Replace the controller if the difference exceeds 1.5 volts

Error: AL99

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Incorrect or damaged battery, or faulty connection
What to do: Verify the correct battery voltage, inspect the battery for damage, and check connections and cables for faults

Error: AL01

What the issue is: Traction and hoist functions not working
Cause of Problem: Control card calibration is out of range or the card is damaged
What to do: Use a handset to check if calibration exceeds 1 volt at neutral. If damaged, replace the control card

Error: AL01

What the issue is: Traction and hoist functions not working
Cause of Problem: Incomplete connection between the control card and controller, or damaged tiller card
What to do: Check connections and use a handset to test the traction reversing switch. Replace the control card if needed

Error: AL02

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Welded contactor tips or a broken motor field circuit
What to do: Test for an open circuit and inspect the connections between the motor field and controller

Error: AL4

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Faulty lowering valve connection or damaged coil
What to do: Check the valve coil connection, check the resistance (approximately 17.7 ohms), and replace the coil or valve cartridge if needed

Error: AL5

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Damaged brake connection or brake coil
What to do: Check the connection and measure the brake coil resistance. Replace if it falls outside the range of 27.36 to 30.24 ohms

Error: AL6

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Faulty traction motor connection, low armature resistance, or shorted motor field
What to do: Inspect the connections and motor armature for shorts, and ensure the motor field resistance is between 0.5 and 1.5 ohms

Error: AL7

What the issue is: Traction functions are reduced at temperatures below 14°F or above 167°F, and stop working above 194°F
Cause of Problem: Controller temperature is too hot or cold, or the sensor is defective
What to do: Move the truck to a temperature-controlled area and use a handset to check if the controller temperature matches the room temperature. Replace the controller if necessary

Error: AL8

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Overcurrent in a driven component
What to do: Check the main harness, contactor, brake, and valve coils for proper resistance

Error: AL10

What the issue is: Traction and hydraulic functions not working
Cause of Problem: Damaged controller, wire connection, or short circuit
What to do: Cycle the key switch and inspect the wiring. Replace the controller if the problem persists

Error: AL94

What the issue is: Traction and hydraulic functions not working for one minute
Cause of Problem: The controller is installing hour meter memory from the MDI display after replacement
What to do: No action needed; functions will resume once the data transfer is complete

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