D250E Series II, D300E Series II, D350E Series II and D400E Series II Articulated Trucks Power Train Electronic Control System Caterpillar

Illustration 1	g00483589
Schematic Of The Position Sensor For The Shift Lever

This diagnostic code is recorded when the ECM reads the signal voltage of the position sensor as being too high.

The possible causes of this diagnostic code are listed:

• Wire M997-PU is shorted to +battery.

• The sensor is faulty.

• The ECM is faulty. This is unlikely.

Note: If the machine is shutdown and the diagnostic code was active, the machine will NOT start again until the diagnostic code has been cleared. In order for the machine to start, the sensor must indicate the NEUTRAL position.

The results of this diagnostic code are listed:

• The machine will not shift.

• The transmission will remain in the current gear.

• The lockup clutch solenoid will disengage.

1. CHECK THE SENSOR.

   1. Turn the disconnect switch and the key start switch to the ON position.

   2. Ensure that the diagnostic code is present.

   3. Observe the status of the diagnostic code. Then, disconnect the machine harness from the sensor.

      Expected Results: If the sensor is not the cause of the diagnostic code, the diagnostic code remains present. If the sensor is faulty, the diagnostic code is NO longer present.

      Results:

      • OK - The diagnostic code remains present. The sensor is not faulty. The machine harness or the ECM may be faulty. Proceed to 2.

      • NOT OK - The diagnostic code is NO longer present. The machine harness is correct and the ECM is operating properly. The sensor is faulty. Replace the sensor. Verify that the new sensor corrects the problem. STOP.

2. CHECK THE SIGNAL CIRCUIT.

   1. Turn the key start switch and the disconnect switch to the OFF position.

   2. The machine harness remains disconnected from the sensor.

   3. Disconnect the J1 and J2 connector from the ECM.

   4. At the J2 connector for the ECM, measure the resistance from contact J2-5 (wire M997-PU) to all other J1 and J2 contacts.

      Expected Result: The resistance should be greater than 5000 ohms.

      Results:

      • YES - The resistance is greater than 5000 ohms. The harness is correct. Proceed to 3.

      • NO - The resistance is not greater than 5000 ohms for each measurement. There is a short in the harness. The short is in the wire with the low resistance measurement. Repair the harness or replace the harness. STOP.

3. CHECK THE RETURN CIRCUIT FOR AN OPEN.

   1. The sensor remains disconnected.

   2. The disconnect switch and the key start switch remain in the OFF position.

   3. The machine harness connectors remain disconnected from the ECM.

   4. At the J1 connector for the ECM, measure the resistance between the return contact J1-15 (wire J764-BR) and contact B (wire J764-BR) at the sensor.

      Expected Result: The resistance is less than 5000 ohms.

      Results:

      • YES - The resistance is less than 5000 ohms. The harness resistance is correct. Proceed to 4.

      • NO - The resistance is greater than 5000 ohms. The return circuit of the harness has failed. There is an open in the return wire (J764-BR). Repair the machine harness or replace the machine harness. STOP.

4. CHECK IF THE DIAGNOSTIC CODE REMAINS.

   1. Inspect the contacts and clean the contacts of the harness connectors.

   2. Reconnect all harness connectors.

   3. Turn the disconnect switch and the key start switch to the ON position.

   4. Check if the diagnostic code is active.

      Expected Result: The diagnostic code is NOT active.

      Results:

      • YES - The diagnostic code is NO longer active. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation. STOP.

      • NO - The diagnostic code remains active. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Testing And Adjusting, "Electronic Control Module (ECM) - Replace". STOP.