561N, 572R Series II and 572R Pipelayers and D10R, D11R, D5M, D5N, D6M, D6N, D6R, D6R Series II, D7R, D7R Series II and D8R Series II Track-Type Tractors Power Train Electronic Control System Caterpillar

Illustration 1	g00608970
Schematic of the Position Sensor (Right Steer)

This diagnostic code is for the Position Sensor (Right Steer).

This diagnostic code is recorded when the signal for the position of the right steering lever is out of range.

The possible causes for this diagnostic code are listed below:

• The +Battery circuit (140-BU(Blue)) from the electrical system to the sensor is open.

• The return circuit (G939-PK(Pink)) is open.

• The signal circuit is shorted to +battery or shorted to ground.

• The signal circuit is open or the sensor is disconnected.

• The sensor linkage is broken.

• The sensor has failed.

• The ECM has failed. This is unlikely.

System Response:

Note: Ensure that the diagnostic code for the sensor is on hold and that the diagnostic code indicator shows "SERV CODE". This procedure can cause new diagnostic codes to be recorded. Ignore these created problems. When the procedure is completed, clear the created diagnostic codes.

Test Step 1. CHECK THE OPERATION OF THE SENSOR.

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

2. Access Component Data Display Mode. View the value of CID 0677. See Testing and Adjusting, "Using Caterpillar Monitoring System to Determine Diagnostic Codes".

3. Disconnect the machine harness from the sensor. Observe the value and note the value that is showing for the sensor signal.

4. At the machine harness, place a jumper from contact "B" (the return circuit) to contact "C" (signal). Observe the value and note the value that is showing for the sensor signal.

Expected Result:

When the machine harness is disconnected from the sensor, the value that is shown should be "100". When the jumper is installed, the value that is shown should be "000".

Results:

• OK - When the machine harness is disconnected from the sensor, the value that is shown is "100". When the jumper is installed, the value that is shown is "000".

  Repair: The machine harness and the ECM are operating properly. The sensor has failed. Check the mechanical assembly of the sensor. Ensure that the sensor is moving properly when the steer lever is pulled and released. If there is no problem with the mechanical assembly of the sensor, replace the position sensor. DO NOT disassemble the mechanical part of steering lever. Disassembly and reassembly of the mechanical part of lever can result in a malfunctioning mechanism because the component can be misaligned.

  STOP

• NOT OK - When the machine harness is disconnected from the sensor, the value that is shown is not "100". When the jumper is installed, the value that is shown is not "000". The machine harness or the ECM may have failed. Proceed to Test Step 2.

Test Step 2. CHECK THE +BATTERY CIRCUIT AT THE SENSOR.

1. The key start switch remains ON. The machine harness remains disconnected from the sensor.

2. At the machine harness for the sensor, measure the voltage (VDC) between contact "A" (+Battery) and frame ground.

Expected Result:

The voltage should measure 9.0 to 32 VDC.

Results:

• OK - The voltage measures 9.0 to 32 VDC. The +battery circuit is correct. Proceed to Test Step 3.

• NOT OK - The voltage does not measure 9.0 to 32 VDC.

  Repair: The +battery circuit (140-BU(Blue)) in the machine harness is open. Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK THE RETURN CIRCUIT.

1. The machine harness remains disconnected from the sensor.

2. Turn the key start switch to the OFF position.

3. At the machine harness connector for the sensor, measure the resistance between contact "B" (the return circuit) and frame ground.

Expected Result:

The resistance should measure 20 ohms or less.

Results:

• OK - The resistance measures 20 ohms or less. Proceed to Test Step 4.

• NOT OK - The resistance does not measure 20 ohms or less. The return circuit is correct.

  Repair: The return circuit (G939-PK(Pink)) in the machine harness is open. Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK THE SIGNAL CIRCUIT FOR AN OPEN.

1. The machine harness remains disconnected from the sensor.

2. Turn the key start switch to the OFF position.

3. Disconnect the machine harness connectors J1 and J2 from the ECM.

4. At the machine harness connector for the sensor, place a jumper between contact "C" and contact "B".

5. At the machine harness connectors J1 and J2, measure the resistance from the sensor signal contact to J1-15 (the return circuit) and to J1-16 (the return circuit).

Expected Result:

There should be less than 5.0 ohms resistance.

Results:

• OK - There is less than 5.0 ohms resistance. The signal circuit in the machine harness is correct. Proceed to Test Step 5.

• NOT OK - There is not less than 5.0 ohms resistance.

  Repair: The signal circuit is open in the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK THE SIGNAL CIRCUIT FOR A SHORT.

1. The key start switch remains OFF. The machine harness remains disconnected from the sensor.

2. If a jumper was used in a previous step, remove the jumper.

3. At machine harness connector J1 and J2, measure the resistance from the signal contact of the sensor to all sources of positive voltage. The possible sources of positive voltage are contacts J1-1, J1-4, J1-6, J1-8, J1-10, J1-11, J1-12, J1-17, J1-18, J1-40, J2-1, J2-2, J2-7, J2-8, J2-13, J2-19, and J2-37. At machine harness connector J1 and J2, measure the resistance from the signal contact of the sensor to ground. The possible sources of ground are contact J1-2, contact J1-5, contact J1-7, contact J1-15, contact J1-16, contact J2-3 and frame ground.

Expected Result:

The resistance should be greater than 5000 ohms for each measurement.

Results:

• OK - The resistance is greater than 5000 ohms for each measurement. The machine harness is correct. Proceed to Test Step 6.

• NOT OK - The resistance is not greater than 5000 ohms for each measurement.

  Repair: There is a short in the machine harness. The short is between the signal circuit and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.

  STOP

Test Step 6. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.

1. Clean the contacts of the harness connectors.

2. Reconnect all harness connectors.

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

4. Enter service mode of the Caterpillar Monitoring System and clear all inactive diagnostic codes.

5. Operate the machine.

6. Determine if the diagnostic code for the sensor is present.

Expected Result:

The diagnostic code for the sensor is present. "SERV CODE" is showing.

Results:

• YES - The diagnostic code for the sensor is present. "SERV CODE" is showing.

  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. See the Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The diagnostic code for the sensor is not present. "SERV CODE" is not showing.

  Repair: The problem does not exist at this time. The initial problem 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