Yale 522614-7 – Engine Control Unit (ECU) / Vehicle System Manager (VSM): Throttle Not at Limp Mode Position (GM Engines Only)

The electronic throttle mechanism is sticky or failing to return to its designated 'limp home' default position. The underlying cause is typically a mechanically sticky throttle body, a failing Throttle Position Sensor (TPS), or a faulty accelerator pedal position sensor.

• Yale and Hyster Forklifts
• GM 2.4L (4-cylinder) engines
• GM 4.3L (V6) engines
• Yale Veracitor VX series
• GLC050VX
• GLP060
• GLC070VX

1. 1

   Perform a hard reset by turning the forklift's power to OFF for no less than 30 seconds, then turn it back to ON to see if the DTC clears.

2. 2

   Conduct a visual inspection of all connectors and wiring associated with the throttle body and the accelerator pedal, looking for open circuits, shorts to ground, or damaged pins.

3. 3

   Perform a live test to check for a sticky mechanism by starting the engine and exercising the accelerator pedal in neutral. For GM 2.4L engines, idle should be 775 to 825 RPM and full pedal 2675 to 2725 RPM. For GM 4.3L engines, idle should be 725 to 775 RPM and full pedal 2375 to 2425 RPM.

1. 1

   Clean the Throttle Body

   Remove the intake hose and inspect the throttle body butterfly valve for heavy carbon buildup. Clean it thoroughly with throttle body cleaner and a soft brush.

2. 2

   Test the Pedal Sensor

   If cleaning does not resolve the issue, use a multimeter (preferably analog) or a diagnostic scanner to sweep the Accelerator Pedal Position Sensor. Ensure the voltage increases smoothly without dead spots.

3. 3

   Replace Faulty Components

   If the throttle body is mechanically binding internally or the integrated TPS has failed, replace the entire throttle body assembly. If the pedal sensor has dead spots, replace the accelerator pedal assembly.

4. 4

   Recalibration

   Whenever you replace a drive-by-wire component (Throttle Body or Accelerator Pedal Position Sensor), you MUST recalibrate the system via the dash display or diagnostic software, otherwise, the ECU will continue to throw position errors.

5. 5

   Clear Codes

   Clear the fault codes and test drive the forklift to verify the repair.