DD15 SPN 2798/FMI 4 Troubleshooting

SPN 2798/FMI 4

This diagnosis is typically injector # 4, 5, or 6 needle control valve circuit is shorted to ground.‪

Check as follows:‪

1. Disconnect the Rear Injector Harness 14–pin connector.
2. Inspect the Rear Injector Harness 14–pin connector for bent or spread pins, inspect the connector seal for damage (signs of water or oil intrusion).
   1. If the water or oil intrusion, bent or spread pins are found, repair as necessary.
   2. If connector shows no signs of damage, go to the next step.
3. Measure the resistance between pin 1 on the valve cover side of the Rear Injector Harness 14–pin connector and ground. If you are using J-48671–10 , measure between injector #4 pin 3 and ground.
   
   1. If the resistance is less than 3 Ω, go to step 13 .
   2. If the resistance is greater than 3 Ω, go to the next step.
4. Remove the upper valve cover.
5. Disconnect injector #4.
6. Measure the resistance between pin 1 on the valve cover side of the Rear Injector Harness 14–pin connector and ground. If you are using J-48671–10 , measure between injector #4 pin 3 and ground.
   1. If the resistance is greater than 3 Ω, replace the #4 injector. Refer to “99.2.1 Verify Repairs” .
   2. If the resistance is less than 3 Ω, go to the next step.
7. Disconnect injector #5.
8. Measure the resistance between pin 1 on the valve cover side of the Rear Injector Harness 14–pin connector and ground. If you are using J-48671–10 , measure between injector #5 pin 3 and ground.
   1. If the resistance is greater than 3 Ω, replace the #5 injector. Refer to “99.2.1 Verify Repairs” .
   2. If the resistance is less than 3 Ω, go to the next step.
9. Disconnect injector #6.
10. Measure the resistance between pin 1 on the valve cover side of the Rear Injector Harness 14–pin connector and ground. If you are using J-48671–10 , measure between injector #6 pin 3 and ground.
    1. If the resistance is greater than 3 Ω, replace the #6 injector. Refer to “99.2.1 Verify Repairs” .
    2. If the resistance is less than 3 Ω, replace the under valve cover injector harness. Refer to “99.2.1 Verify Repairs” .
11. Disconnect the 120–pin MCM connector.
12. Measure the resistance between pin 1 on the valve cover side of the Rear Injector Harness 14–pin connector and ground.
    1. If the resistance is less than 3 Ω, repair the short to ground between pin 19 of the MCM 120–pin connector and pin 1 of the Rear Injector Harness 14–pin connector. Refer to “99.2.1 Verify Repairs” .
    2. If the resistance is greater than 3 Ω, call the Detroit Diesel Customer Support Center at 313–592–5800 for MCM replacement authorization.

Section 99.2.1
Verify Repairs

Verify repairs as follows:‪

1. Turn ignition OFF.
2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
3. Clear codes with DDDL 7.0 or latest version.
   

   ENGINE EXHAUST ‪
   To avoid injury from inhaling engine exhaust, always operate the engine in a well-ventilated area. Engine exhaust is toxic.‪

4. Start and bring engine up to operating temperature (over 140°F/60°C).
5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes.