Conditions Which Generate This Code:
| Illustration 1 | g03371919 |
Schematic of the Ignition Key Reader | |
This diagnostic code is associated with the Ignition Key Reader. This diagnostic code is recorded when the Machine ECM does not receive expected information from the key reader module over the data link.
Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected.
Test Step 1. CHECK FOR POWER TO THE KEY READER MODULE.
- With the key switch in the ON position, check for system voltage between pin 1 (wire 308-YL) and pin 2 (wire 202-BK) of the key reader module.
Expected Result:
The voltage that is measured is approximately system voltage.
Results:
- YES - The voltage that is measured is approximately system voltage. The voltage is correct. Proceed to Test Step 2.
- NO - System voltage is NOT present. The wiring harness has failed.
Repair: Check the wiring harness for signs of damage. Repair the machine harness or replace the machine harness.
STOP
Test Step 2. CHECK THE CAN DATA LINK WIRING OF THE MACHINE HARNESS FOR AN OPEN CIRCUIT.
- Disconnect the J2 harness connector from the machine ECM.
- Disconnect the key reader harness.
- Install a jumper wire between pins 3 and pin 4 of the machine harness connector for the key reader.
- At the J2 connector of the machine ECM, measure the resistance between pin J2-67 (wire F711-GN) and pin J2-68 (wire F712-GY) of the connector for the machine ECM.
Expected Result:
The resistance is less than 5 ohms.
Results:
- NO - The resistance is greater than 5 ohms between pin J2-67 and pin J2-68. The wiring for the CAN link, between the ECM and the key reader module is NOT correct.
Repair: Check the wiring harness for signs of damage. Repair the machine harness or replace the machine harness.
STOP
- YES - The resistance is less than 5 ohms between pin J2-67 and pin J2-68. The wiring is correct. Proceed to Test Step 3.
Test Step 3. CHECK THE CAN JUMPER FOR AN OPEN
- The wiring harness remains disconnected.
- Disconnect the machine harness from the back of the instrument cluster.
- Measure resistance from pin 5 (wire N740-WH) to pin 6 (wire N740-WH) on the machine harness connector for the instrument cluster.
Expected Result:
The resistance is less than 5 ohms.
Results:
- OK - The resistance is less than 5 ohms. Precede to test step 4.
- NOT OK - The resistance is greater than 5 ohms.
Repair: Repair or replace the jumper wire.
STOP
Test Step 4. CHECK THE CAN DATA LINK WIRING OF THE MACHINE HARNESS FOR A SHORT TO GROUND.
- The wiring harness remains disconnected.
- The jumper wire remains installed.
- Disconnect the Machine harness connections from the Engine ECM.
- Measure the resistance between pin J2-67 (wire F711-YL) of the machine harness connector for the machine ECM and the oven door ground.
Expected Result:
The resistance is greater than 5000 ohms.
Results:
- YES - The resistance is greater than 5000 ohms. The resistance is correct. Proceed to Test Step 5.
- NO - The resistance is less than 5000 ohms. The wiring harness is shorted to the ground.
Repair: Check the wiring harness for signs of damage. Repair the machine harness or replace the machine harness.
STOP
Test Step 5. CHECK THE CAN DATA LINK WIRING OF THE MACHINE HARNESS FOR A SHORT TO + BATTERY.
- The wiring harness remains disconnected.
- The jumper wire remains installed.
- Measure the resistance between pin J2-67 (wire F711-YL) of the machine harness connector for the machine ECM connector and all sources of + battery.
Expected Result:
Resistance is greater than 5000 ohms.
Results:
- YES - The resistance is greater than 5000 ohms. The resistance is correct. Proceed to Test Step 6.
- NO - The resistance is less than 5000 ohms. The wiring harness is shorted to the + battery circuit.
Repair: Check the wiring harness for signs of damage. Repair the machine harness or replace the machine harness.
STOP
Test Step 6. CHECK THE CAN DATA LINK TERMINATION RESISTOR FOR AN OPEN CIRCUIT.
- Check the resistance between pins 17 and 37 of the Engine ECM.
Expected Result:
The resistance is approximately 120 ohms.
Results:
- YES - The resistance is approximately 120 ohms. The resistance is correct. The Machine ECM may have failed.
Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace"
STOP
- NO - The resistance is greater than 120 ohms. The Engine ECM may have failed.
Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace"
STOP
