Yale 523550-3 – Controller / ECU (Vehicle System Manager / VSM): Start Relay Control OORH (Out Of Range High)

The control system has detected a voltage on the start relay control circuit that is higher than expected. Specifically, the system is seeing a short circuit to battery voltage on the output driver circuit that controls the start relay.

• Yale and Hyster Forklifts
• Yale Veracitor/Fortis lines
• GLP models
• GDP models
• GLC models

1. 1

   Check the Battery and Base Power: Ensure the system has stable primary power (12.2–12.7V with the engine off). Over-voltage from a faulty alternator regulator (>16V) can sometimes trigger OORH codes.

2. 2

   Inspect the PDM (Power Distribution Module): Locate the start relay inside the PDM. Check the PDM for internal corrosion, melted traces, or water ingress that could be bridging a constant battery power circuit to the start relay control pin.

3. 3

   Test the Wiring Harness: Disconnect the harness at the controller and at the PDM. Use a multimeter to check for continuity between the start relay control wire and any switched/unswitched battery power sources. A reading near 0 ohms to a power wire indicates a dead short in the harness.

4. 4

   Test the Start Relay: Check the relay coil resistance (typically ~80–200 ohms). Ensure the relay is not internally shorted.

5. 5

   Test the Controller Output: If the harness, PDM, and relay all test perfectly fine and no shorts to battery are found in the wiring, the fault lies within the controller's internal circuitry (a failed output driver stuck 'high').

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before servicing the PDM or controller to prevent accidental arcing.

2. 2

   Resolve Harness/PDM Shorts

   If a short to battery is found in the wiring harness, locate the chafed/damaged section of the wire and repair it using proper soldering and heat-shrink techniques, or replace the affected harness section. If the short is internal to the Power Distribution Module (PDM), the PDM must be unbolted from the battery tray/bracket and replaced.

3. 3

   Replace the Start Relay

   If the relay coil is internally shorted or damaged, pull the old relay from the PDM and install a new one.

4. 4

   Replace the Controller

   If diagnostic tests prove the harness and PDM are good, the controller has suffered a functional failure. Remove the controller, install a replacement unit, and flash/program it to the truck's specific serial number using Yale diagnostic software.

5. 5

   Clear Codes and Test

   Reconnect the battery, clear the fault codes from the system, and cycle the ignition to verify the code does not return and the truck starts normally.