The engine cooling fan speed has exceeded the trip point of 2300 rpm.
System Response:
The Electronic Control Module (ECM) logs the event.
Low power may be experienced due to the increased horsepower that is needed to continuously drive the fan.
Test Step 1. Check for Active Diagnostic Codes
- Turn the keyswitch to the OFF position.
- Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools" for instructions.
- Turn the keyswitch to the ON position.
- Observe the active diagnostic code screen on Cat ET. Wait at least 30 seconds so that any codes may become active.
- Check for a 291-12 Engine Cooling Fan Solenoid malfunction that is active or logged.
Expected Result:
A 291-12 diagnostic is active or logged.
Results:
- OK - The code is active or logged.
Repair: An active 291-12 latches the speed of the engine cooling fan to the speed of the engine. This may be the cause of the event. Refer to Troubleshooting, "CID 0291 FMI 12 Engine Cooling Fan Solenoid malfunction" for troubleshooting information.
STOP
- Not OK - The code is not active or logged.
Repair: There may be a mechanical problem with the fan drive. Refer to Troubleshooting, "Engine Fan Control Solenoid Circuit - Test" in order to test the operation of the solenoid for the engine cooling fan.
STOP