Yale 168-4 – VSM / ECU: System Battery Voltage OORL

The controller is detecting that the system's battery voltage has dropped below normal operating parameters (typically below 9.0 volts) for a sustained period (e.g., 5 seconds) while the keyswitch is in the ON position or the engine is running.

• Yale and Hyster Forklifts
• Yale GLP050VX
• Yale GDP45
• Yale GLP20SVX
• Yale 80VX
• Hyster S60FT
• Hyster 110HFT

1. 1

   Clear the Code: Turn the power to OFF for no less than 30 seconds, and then turn it back to ON to see if the code clears.

2. 2

   Battery Voltage Test: Use a multimeter to check the battery voltage. Resting voltage should be around 12V, and it should not drop below 9V during operation.

3. 3

   Alternator Output Test: Check the voltage with the engine running. Normal output from the alternator should be around 13.8V to 14.5V. If it is not charging, the alternator is likely the culprit.

4. 4

   Visual Wiring Inspection: Conduct a quick visual inspection of all connectors and wiring associated with the VSM and ECU power supply. Look for corrosion, loose pins, or shorts to ground.

5. 5

   Parasitic Draw Test: Check for excessive current draw when the forklift is turned off, which could be draining the battery between shifts.

1. 1

   Reset the System

   Perform the 30-second power cycle to verify if the fault is active or stored.

2. 2

   Inspect and Repair Wiring

   If the visual inspection reveals damaged wiring or corroded connectors at the VSM/ECU, repair or replace the affected harness sections.

3. 3

   Replace the Battery

   If the battery fails a load test, fluctuates wildly (e.g., jumping between 8V, 10V, and 12V), or drains rapidly when parked, replace the battery.

4. 4

   Replace the Alternator

   If the battery is good but the system voltage stays below 13.8V with the engine running, or if you hear whining/grinding noises from the alternator bearings, replace the alternator.

5. 5

   Controller Replacement (Last Resort)

   If the battery, alternator, and wiring all test perfectly but the VSM/ECU still reads low voltage, the controller itself has suffered a functional failure and must be replaced or reflashed.