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

This diagnostic code is recorded when the main display module does not receive expected information. For example, engine speed or actual gear information is not received from other electronic control modules through the CAT Data Link. This diagnostic code causes the readouts, that are dependent upon the CAT Data Link information, to indicate abnormal values.

The possible causes of this diagnostic code are listed in the order of probability:

• A poor electrical connection at a machine harness connector

• A circuit in the CAT Data Link is shorted to ground.

• The CAT Data Link circuit in the machine harness is shorted to +battery.

• The CAT Data Link circuit in the machine harness is open.

Ensure that the desired CID 0248 and FMI 09 is on-hold. Ensure that the "SERV CODE" indicator shows "SERV CODE".

Note: An electronic control module (ECM) which uses the CAT Data Link is faulty.

1. CHECK FOR OTHER CODES.

   1. Check other electronic control modules for a similar diagnostic code. If a similar diagnostic code is found, exit this test and perform the corresponding procedure(s) for the other diagnostic codes that are shown.

      Expected Result: Other diagnostic codes are showing.

      Results:

      • YES - Exit this procedure and perform the other CID FMI procedures for the CID FMI diagnostic codes shown. STOP.

      • NO - There are no other CID FMI diagnostic codes showing. Proceed to Step 2.

2. INSPECT THE HARNESS CONNECTORS.

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

   2. Inspect the connections of the machine harness that are related to the CAT Data Link.

   3. Make sure that connectors are clean and tight.

      Expected Result: The machine harness is correct.

      Results:

      • OK - The machine harness is correct. Proceed to Step 3.

      • NOT OK - The machine harness is not correct. Repair the machine harness or replace the machine harness. STOP.

3. CHECK FOR A SHORT TO GROUND.

   1. The key start switch and the disconnect switch remains OFF.

   2. Disconnect the machine harness from all electronic control modules that use the CAT Data Link.

   3. At the machine harness connector for the main display module, measure the resistance between frame ground and the CAT Data Link circuits (contacts J1-3 and J1-9).

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

      Results:

      • YES - The resistance is less than 5000 ohms. The machine harness is faulty. There is a short between frame ground and the CAT Data Link circuit in the machine harness. Repair the machine harness or replace the machine harness. STOP.

      • NO - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to Step 4.

4. CHECK FOR SHORT TO +BATTERY

   1. The key start switch and the disconnect switch remains OFF.

   2. All related control modules remain disconnected from the machine harness.

   3. At the machine harness connector for the main display module, measure the resistance between +battery (J1-1) and the CAT Data Link circuits (contacts J1-3 and J1-9).

      Expected Result: The resistance is greater than 5000 ohms.

      Results:

      • OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to Step 5.

      • NOT OK - The resistance is less than 5000 ohms. The harness is faulty. There is a short between the +battery and the CAT Data Link circuit in the machine harness. Repair the machine harness or replace the machine harness. STOP.

5. CHECK FOR AN OPEN HARNESS.

   1. The key start switch and the disconnect switch remains in the OFF position.

   2. All related control modules remain disconnected from the machine harness.

   3. Check the continuity of the CAT Data Link circuit in the machine harness.

   4. Measure the resistance from contacts J1-3 and J1-9 of the main display module to the corresponding connector contacts of each related electronic control module.

      Expected Result: The resistance measurement is less than 5 ohms.

      Results:

      • YES - The resistance measurement is less than 5 ohms. The CAT Data Link circuit in the machine harness is correct. The main display module is faulty. Replace the main display module. STOP.

      • NO - The resistance is greater than 5 ohms. The machine harness is faulty. The CAT Data Link circuit is open in the machine harness. Repair or replace the machine harness. STOP.