BODY 5J9798 - Caterpillar

Illustration 1 g06138486
Schematic for the active sensors
Probable Causes
Codes
Short circuit
Open circuit
Supply voltage
Wiring
Electrical connectorsRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Establish communication between Cat® Electronic Technician (ET) and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Turn the keyswitch to ON.
C. Look for "-3", or "-4" active or logged codes.
Codes
Result: A -3 diagnostic code is active.
Proceed to Test Step 2.
Result: A -4 diagnostic code is active.
Proceed to Test Step 3.
2. Create a Short at the Sensor Connector
A. Use a test lamp to create a short between terminal 3 (signal) and terminal 2 (sensor return) at the sensor connector.
B. Turn the keyswitch to ON.
C. Monitor the diagnostic codes on Cat ET. Check for an active -4 diagnostic code for the suspect sensor.
D. Turn the keyswitch to OFF.
Short circuit
Result: A -4 diagnostic code does not become active for the suspect sensor.
Proceed to Test Step 4.
Result: A -4 diagnostic code became active after creating the short at the sensor connector. The wiring is OK.
Repair: Replace the sensor.
If the problem is not resolved, proceed to Test Step 3.
3. Create an Open at the Suspect Sensor Connector
A. Turn the keyswitch to OFF.
B. Disconnect the sensor connector of the suspect sensor with the active -4 diagnostic code.
C. Turn the keyswitch to ON.
D. Monitor the diagnostic codes on Cat ET. Check for an active -3 diagnostic code for the suspect sensor.
E. Turn the keyswitch to OFF.
Open circuit
Result: A -3 diagnostic code did not become active after disconnecting the sensor.
Proceed to Test Step 4.
Result: A -3 diagnostic code became active after disconnecting the sensor. The wiring is OK.
Repair: Replace the sensor.
If the problem is not resolved, proceed to Test Step 4.
4. Check the 5 VDC Supply Voltage at the Sensor Connector
A. Turn the keyswitch to ON.
B. Measure the voltage between pin 1 and pin 2 at the suspect sensor.
5.0 0.2 VDC
Result: The supply voltage is OK.
Repair: Connect the sensor.
Proceed to Test Step 5
Result: The supply voltage is NOT OK. There is a short in the harness to the battery.
Repair: Repair the wiring or replace the harness
If the problem is not resolved, proceed to Test Step 5.
5. Perform the Wiggle Test
Carefully following this procedure is the best way to identify the root cause of an intermittent problem.
A. Turn the keyswitch to ON.
B. Use Cat ET to run the "Wiggle Test".
C. Slowly wiggle the wiring and the connectors between the P2 connector and the sensor. Pay particular attention to the wiring near each connector. Be sure to wiggle all the wiring.
As you wiggle the wiring look for these problems.
1. Loose connectors or damaged connectors
2. Moisture on the connectors or the wiring
3. Damaged that is caused by excessive heat
4. Damage that is caused by chafing
5. Improper routing of wiring
6. Damaged insulation
Wiring
Result: The wiring failed the Wiggle Test.
Repair: There is a problem with the wiring. Repair the wiring or replace the wiring.
Result: The wiring passed the Wiggle Test. The problem may be intermittent.
Repair: Inspect the wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect".
If the wiring looks