CONTROL GP-BUCKET 2Q7890 - Caterpillar

This diagnostic code is recorded under the following conditions:
The transmission is in gear "3F" or "3R".
The service brake pedal is depressed.
The transmission output speed is zero.
The torque converter output speed is not zero.These conditions indicate clutch slippage in the transmission when the torque converter is stalled.Test Step 1. CHECK FOR TORQUE CONVERTER OUTPUT SPEED.
Remove the floorplate that is located in front of the operator's seat.
Operate the machine and perform a torque converter stall test with the transmission in third gear. The service brake must be fully depressed.
Verify that the torque converter output shaft was stopped during the stall test. Expected Result:The torque converter output shaft was stopped during the stall test.Results:
YES - The torque converter output shaft was stopped during the stall test. Proceed to Test Step 2.
NO - The torque converter output shaft was not stopped during the stall test.Repair: The transmission clutches are slipping. Exit this test procedure and perform the appropriate diagnostic procedures for the transmission. STOPTest Step 2. CHECK THE CIRCUIT FOR THE TRANSMISSION SPEED SENSOR.
Connect the Cat ET to the machine. Select the power train controller. View the status group with the torque converter output speed.
Operate the machine at low idle with the transmission in first gear.
Slowly apply the service brake until the machine has stopped.
Observe the following three speeds: Torque converter output speed, Transmission output speed (number 1) and Transmission output speed (number 2). Expected Result:The three speeds decline to zero at the same time.Results:
OK - The three speeds decline to zero at the same time. Proceed to 3.
NOT OK - The three speeds do not decline to zero at the same time.Repair: Exit this test procedure and perform the diagnostic procedure that corresponds to the speed sensor with the problem.STOPTest Step 3. DETERMINE IF THE DIAGNOSTIC CODE IS STILL ACTIVE.Perform the torque converter stall test.Expected Result:There is no active diagnostic code during the stall test.Results:
YES - There is no active diagnostic code during the stall test. The initial problem was probably caused by electronic interference on the signal circuit. Resume normal machine operation. If the problem occurs again, check for recent software releases for the power train controller.STOP
NO - There is still an active diagnostic code during the stall test. Repair: Exit this procedure and perform the diagnostic code procedure again. If the problem persists, the ECM may have failed. Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the power train ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP