DDEC III/IV Single ECM Troubleshooting – Section 81.4 Troubleshoot Maintenance Alert System

Section 81.4
Troubleshoot Maintenance Alert System

The following procedures troubleshoot the Maintenance Alert System.‪

Section 81.4.1
Multiple Code Check

Perform the following steps to check for multiple codes:‪

1. Turn ignition ON.
2. Plug in DT (diagnostic tool).
3. Read active codes.
4. Turn ignition OFF.
   1. If code 98/3 displays with code s 232/0, troubleshoot s 232/0 first.
   2. If code 98/3 displays, refer to "81.4.2 Check Connectors" .

Section 81.4.2
Check Connectors

Perform the following steps to check the connectors: ‪

1. Unplug the oil level sensor (OLS).
2. Turn ignition ON.
3. Read codes.
   1. If code 98/4 displays, check connectors for open, damage or unseated conditions. Refer to "81.4.3 Sensor Check" .
   2. If code 98/3 displays, refer to "81.4.4 Check for Short" .

Section 81.4.3
Sensor Check

Perform the following steps to replace the sensor: ‪

1. Replace the oil level sensor (OLS).
2. Verify the repair. Refer to "81.4.6 Verify Repairs" .

Section 81.4.4
Check for Short

Perform the following steps to check for short:‪

1. Measure resistance between pin B and pin C of the OLS. See Figure "Oil Level Sensor" .
   1. If the reading is less than 10 Ω, cavity #416 is shorted to cavity #976. Repair the short or replace the harness and verify the repair. Refer to "81.4.6 Verify Repairs" .
   2. If the reading is greater than 10 Ω, refer to "81.4.5 Check for Open" .
      

      Figure 1. Oil Level Sensor

Section 81.4.5
Check for Open

Perform the following steps to check for open: ‪

1. Unplug the engine sensor harness connector.
2. Insert a jumper harness between the pins A and B of the OLS connector. Measure resistance between cavity Y2 and L2. See Figure "Oil Level Sensor" .
   1. If reading is greater than 10 Ω, cavity #452 is open. Repair the open or replace the harness; verify the repair. See Figure "Oil Level Sensor" . Refer to "81.4.6 Verify Repairs" .
   2. If the reading is less than 10 Ω, contact Detroit Diesel Technical Service, or try a test ECM.

Section 81.4.6
Verify Repairs

Perform the following steps to verify repairs:‪

1. Plug in all connectors.
2. Start and run the engine for two minutes.
3. Check for codes.
   1. If no codes display, the repair is complete.
   2. If code 98/3 displays, troubleshooting is complete. Review the troubleshooting of the OLS to find the error. Refer to "81.4.1 Multiple Code Check" .