Yale 515-0 – Engine Control Unit (ECU): RPM Greater Than Throttle Command

The engine's actual RPM is higher than what the Electronic Throttle Assembly (ETA) and the Engine Control Unit (ECU) are commanding. The engine is revving higher than the accelerator pedal's requested position, typically caused by unmetered air entering the engine or a mechanical failure in the throttle body.

• Yale and Hyster Forklifts
• Yale VX Series
• GC135VX
• GLC050VX
• GLC020VX-GLC035VX
• GLP060VX
• Hyster FT Series

1. 1

   Check for large leaks in the intake manifold, vacuum lines, and throttle body mating surfaces for unmetered air bypassing the throttle body.

2. 2

   Inspect the Electronic Throttle Assembly (ETA) for mechanical issues, such as carbon buildup causing the throttle plate to stick open, or a binding mechanism.

3. 3

   Check the Engine Control Unit (ECU) for a functional failure if the manifold is sealed and the throttle body is mechanically sound.

1. 1

   Perform visual and auditory inspection

   Inspect the intake manifold and vacuum hoses while the engine is running (if safe to do so) to locate any hissing sounds indicative of a vacuum leak.

2. 2

   Smoke test the intake system

   Perform a smoke test if a leak is suspected but cannot be found visually.

3. 3

   Replace leaking gaskets

   If a leak is found at the intake manifold or throttle body base, remove the component, clean the mating surfaces, and install a new OEM gasket.

4. 4

   Clean or Replace the Throttle Body (ETA)

   Remove the intake hose and inspect the throttle plate. If it is sticking due to carbon, clean it with throttle body cleaner. If the internal mechanical gears/actuators are binding or failing, replace the entire Electronic Throttle Assembly.

5. 5

   Replace the ECU

   If no vacuum leaks are present and the ETA is verified to be in good working order, the engine controller has suffered a functional failure and must be replaced and reprogrammed by a dealer.

6. 6

   Clear Codes

   After repairs, clear the fault codes from the dash display and test drive the forklift to ensure the RPM tracks the throttle command accurately.