CYLINDER HEAD GP 2993521 - Caterpillar

The Engine Control Module (ECM) detects the following conditions:
The "VSL Protection" is not programmed to the programmed "TEL".
The vehicle speed is constant when the engine parameters indicate that the vehicle speed should be changing.
Engine speed is greater than 950 rpm for more than 60 ms.Note: This code typically occurs when someone has tampered with the vehicle speed signal.System Response:Engine rpm is limited to the programmed "VSL Protection" for one hour. If the ECM is providing the speedometer signal, the speedometer will reflect the loss of speed when the problem occurs and the vehicle is moving. Caterpillar Electronic Technician (ET) will display "DIAG" next to "Vehicle Speed" on the status screen while the diagnostic code is active.Possible Performance Effect:The driver may think that the engine power is low and that the engine is unable to reach the expected rpm. The derate will remain for one hour after the fault is no longer active.Troubleshooting:Test Step 1. Perform the following diagnostic procedure: "Vehicle Speed and Speedometer Circuit - Test"Results:
OK - STOP