Yale 524266-31 – Engine Control Unit (ECU): Electronic Throttle Motor/Motor Connections - Short Circuit

The system has detected a short circuit in the electronic throttle control circuit. This is typically caused by a short circuit in the wiring connections between the controller and the throttle body, an internal short circuit within the Electronic Throttle Body (ETB) motor itself, or a failure of the ECU/ETB driver component.

• Yale and Hyster Forklifts
• Yale Veracitor VX series (GLP/GDP 40-90 VX models)
• Bendi B40i4 forklifts

1. 1

   Check for Related Codes: Look for the presence of DTC 524286-31 (ECU - ETB Driver Component Failure). If this code is also present, the internal driver inside the ECU has likely failed.

2. 2

   Listen for Initialization: Turn the ignition key to the ON position and listen for a movement/buzzing sound at the Electronic Throttle Body. It must operate/buzz to indicate the ECU has power and is communicating. If there is no buzz, check the S3000 cable connections.

3. 3

   Relay Voltage Check: Back-probe the Power Latch Relay connector (CPS206) with the key in the OFF position. Pins E, F, and D should have battery voltage.

4. 4

   Wiring Harness Inspection: Inspect the wiring harness between the ECU and the ETB for pinched wires, chafing, or exposed copper that could cause a short to ground or a short to battery voltage.

5. 5

   Motor Resistance Test: Unplug the ETB and test the motor terminals with a multimeter to check for an internal short circuit.

1. 1

   Preparation

   Stop the forklift, apply the parking brake, turn the ignition switch OFF, and disconnect the battery.

2. 2

   Wiring Repair

   If the diagnostic checks revealed a short in the wiring harness, repair the damaged section of the wire or replace the connector pigtail.

3. 3

   Throttle Body Replacement

   If the wiring is intact but the ETB motor is internally shorted, remove the intake hosing, unplug the electrical connector, unbolt the faulty Electronic Throttle Body, and install a new unit.

4. 4

   ECU Replacement

   If both the wiring and the ETB test perfectly fine, the ECU's internal ETB driver has failed (often confirming code 524286-31). The ECU will need to be replaced or sent out for repair.

5. 5

   Relearn Procedure

   If the Electronic Throttle Body is replaced, you must perform an Air Idle Volume Learn (Fast TAS Normal) procedure. Start the engine and let it warm up to 76 to 84 degrees Celsius. Open the PC diagnostic program (version 3.1 or higher). Select the truck model and run the Air Idle Volume Learn procedure so the ECU can calibrate to the new throttle body.