DDEC III/IV Single ECM Troubleshooting – Section 82.4 Troubleshooting Maintenance Alert System

Section 82.4
Troubleshooting Maintenance Alert System

The following procedure will troubleshoot the Maintenance Alert System (MAS): ‪

Section 82.4.1
Read Codes

Perform the following steps to read codes:‪

1. Turn ignition ON.
2. Plug in the DT.
3. Read active codes.
4. Record or print codes and turn the ignition OFF.
   1. If code 98/4 displays with 232/1, troubleshoot 232/1 first.
   2. If code 98/4 displays, refer to "82.4.2 Check for Open" .

Section 82.4.2
Check for Open

Perform the following steps to check for open: ‪

1. Unplug the sensor.
2. Insert the jumper wire between cavities B and C.
3. Turn ignition ON.
4. Read codes.
   1. If code 98/3 displays, check the connectors for damaged, open or broken pins. If everything checks out, refer to "82.4.3 Check for Short" . If damage is noted, repair and verify the repairs. See Figure "Oil Level Sensor" . Refer to "82.4.5 Verify Repairs" .
   2. If code 98/4 displays, refer to "82.4.4 Check for Open" .
      

      Figure 1. Oil Level Sensor

Section 82.4.3
Check for Short

Perform the following steps to check for a short:‪

1. Measure resistance between cavity A #452 and C #416, and again between cavity A #452 and B #906 of the sensor connector. See Figure "Oil Level Sensor" .
   1. If either reading is less than 10 Ω, that wire is shorted to the sensor return #452. Repair the short or replace the harness. Verify the repair. Refer to "82.4.5 Verify Repairs" .
   2. If both readings are greater than 10 Ω, replace the sensor. Verify the repair. Refer to "82.4.5 Verify Repairs" .

Section 82.4.4
Check for Open

Perform the following steps to check for open: ‪

1. Unplug the 30–pin engine sensor connector at the ECM.
2. Measure resistance with the jumper still plugged in, between cavity L2, #906 and W1, #416. See Figure "Oil Level Sensor" .
   1. If the reading is greater than 10 Ω, either the #416 or #9706 wire is open. Repair the open or replace the harness. Verify the repair. Refer to "82.4.5 Verify Repairs" .
   2. If the reading is greater than 10 Ω, replace the sensor. Verify the repair. Refer to "82.4.5 Verify Repairs" .
      

      Figure 2. Oil Level Sensor

Section 82.4.5
Verify Repairs

Follow these steps to verify the repair:‪

1. Plug in all connectors.
2. Start and run the engine for five minutes.
3. Plug in DT and read active codes.
   1. If no codes display, troubleshooting is complete. Return the engine to service.
   2. If code 98/4 displays, review the MAS troubleshooting to find the error or contact DDC Technical Service for assistance. Refer to "82.4.1 Read Codes" .