Yale 168-1 – VSM (Vehicle System Manager) or ECU (Engine Control Unit): System Battery Voltage OORL

The system's electrical voltage has dropped below the minimum acceptable threshold required for normal operation.

• Yale and Hyster Forklifts
• Yale and Hyster internal combustion forklifts
• Yale VX series
• Hyster FT series
• S50CT
• H50CT
• models equipped with Cummins (e.g., QSB 3.3L), GM, Mazda, and Yanmar engines

1. 1

   Check main system fuses and inspect the wiring harness for shorts or open circuits

2. 2

   Verify the integrity of the ignition circuit and wiring

3. 3

   Test the battery's resting voltage and ability to hold a load

4. 4

   Verify that the alternator is outputting the correct charging voltage when the engine is running

5. 5

   Determine if the forklift is being used for cycles that are too short to adequately recharge the battery

6. 6

   Check for a parasitic battery drain (static current consumption) when the truck is turned off

1. 1

   Visual & Fuse Inspection

   Start by checking the main electrical distribution panel for any blown fuses. Inspect the wiring harness and ignition wiring for visible damage, corrosion, or loose connections.

2. 2

   Battery Test

   Measure the battery voltage with the machine off. Perform a load test on the battery. If the battery fails the load test or has a dead cell, replace it.

3. 3

   Alternator / Charging System Test

   Start the forklift and measure the voltage at the battery terminals. If the voltage does not rise to the proper charging level (typically 13.5V - 14.5V), the alternator is failing and must be replaced. (Note: OEM manuals suggest checking for alternator/pulley size alternatives if the application requires it).

4. 4

   Parasitic Draw Test

   If the battery and alternator are functioning normally, turn the truck off and use a multimeter in series with the negative battery terminal to measure quiescent current draw. If the draw is excessively high, isolate the circuit causing the drain by pulling fuses one by one.

5. 5

   Operational Adjustment

   If no mechanical or electrical faults are found, the issue may be operational. Advise the operator to allow the truck to run longer to sufficiently charge the battery.

6. 6

   Clear Codes

   Once the faulty component is replaced or the wiring is repaired, clear the DTCs from the system and test drive the forklift to ensure the code does not return.