Yale 522604-3 – VSM (Vehicle System Manager) or ECU (Engine Control Unit): Fuel Run Relay Control OORH

The system's controller has detected that the control circuit for the fuel run relay is experiencing a voltage that is higher than expected, typically caused by a short circuit to a battery power source.

• Yale and Hyster Forklifts
• Yale and Hyster forklifts (2005 and newer)
• Yale VX series (GC/GLC VX models)
• Hyster FT series

1. 1

   Inspect the PDM (Power Distribution Module) for signs of melted plastic, corrosion, or internal bridging that could cause a short to battery power.

2. 2

   Disconnect the battery and harness connectors at the PDM and Controller, then test the fuel run relay control wire for a short to any switched or unswitched battery power lines.

3. 3

   Swap the fuel run relay with a known good relay of the same type (e.g., horn or light relay) to see if the internal coil has shorted to the control side.

4. 4

   If the harness and PDM test fine with no shorts to battery voltage, verify if the controller has a stuck internal driver.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery terminal to prevent accidental shorts during repair.

2. 2

   Isolate the Short

   Based on the diagnostic checks, locate the exact point of the short circuit.

3. 3

   Repair Wiring/PDM

   If the wiring harness is chafed and touching a power wire, repair the damaged section using OEM-approved wire splicing techniques and heat shrink. If the PDM is internally shorted, the PDM board/block must be replaced.

4. 4

   Replace the Relay

   If the relay itself is faulty or melted, replace it with a new OEM relay.

5. 5

   Replace the Controller

   If all wiring and the PDM are intact, the VSM or ECU has suffered a functional failure. Replace the controller and flash/program it to the truck using the Yale PC Service Tool.

6. 6

   Clear Codes

   Reconnect the battery, turn the ignition on, and clear the fault codes from the dash display to verify the repair.