Yale 522604-5 – Engine Control Module (ECM) or Vehicle System Manager (VSM): Fuel Relay not Functioning

The control system has detected a failure in the fuel pump/run relay circuit. The system expects to see a specific electrical signature when commanding the fuel relay to close. When it does not, it triggers this code.

• Yale and Hyster Forklifts
• 2005 and newer Yale and Hyster internal combustion forklifts
• Yale Veracitor VX series
• Hyster Fortis FT series
• H90FT
• GC/GLC 040-120
• GDP series

1. 1

   Relay Swap Test: Locate the Power Distribution Module (PDM) / fuse box. Find the Fuel Relay and swap it with a known-good relay of the exact same type (such as the horn or work light relay).

2. 2

   Visual Inspection: Inspect the relay socket in the PDM for pushed-out pins, severe corrosion, or melted plastic.

3. 3

   Harness Continuity Test: Using a multimeter, check the wiring harness between the relay coil control pin at the PDM and the corresponding pin on the ECU/VSM. You are looking for an Open Circuit (infinite resistance).

4. 4

   Controller Output Test: Verify if the ECU is actually sending the command signal (ground or voltage, depending on the chassis wiring) to the relay coil when the key is turned to the ON position.

1. 1

   Disconnect the Battery

   Always disconnect the negative battery terminal before performing electrical repairs or testing ECU pins.

2. 2

   Replace the Relay

   If the diagnostic swap test proved the relay was faulty (coil open circuit), install a new OEM relay into the PDM.

3. 3

   Repair the Harness

   If the multimeter test showed an open circuit in the wiring, trace the wire from the PDM to the ECU. Locate the break, chafed wire, or damaged connector pin. Repair the wire using proper automotive-grade soldering and heat-shrink tubing, or replace the damaged pin terminal.

4. 4

   Replace the Controller

   If the wiring harness has perfect continuity, the relay is brand new, and the code 522604-5 persists, the official literature dictates a Functional Failure in Controller. The ECM/VSM will need to be replaced and calibrated to the truck by a dealer.

5. 5

   Clear Codes

   Reconnect the battery. Use the dash display or the PC service tool to clear the stored fault codes. Cycle the key and verify the fuel relay clicks and the engine starts.