Series 60 – SPN 651 – INJECTOR #1 NEEDLE VALVE NOT OPERATING NORMALLY

59.1 SPN 651/FMI 14
This diagnosis is typically an open circuit, short to ground or short to power.
59.1.1
Open Circuit, Short to Ground or Short to Power Check
Check as follows:
1. Check for multiple codes.
[a] If fault code 168/1 is active in addition to other codes, service 168/1 first.
Refer to section 32.2.
[b] If fault 652/14 and 653/14 are active in addition to 651/14, go to step 2.
[c] If only fault code 651/14 is active, go to step 10.
2. Turn the ignition OFF.
3. Disconnect the Front Injector Harness 12–pin connector.
4. Inspect the Front Injector Harness 12–pin connector for bent or spread pins, inspect the
connector seal for damage (signs of water or oil intrusion).
[a] If the water or oil intrusion, bent or spread pins are found, repair as necessary.
Refer to section 59.1.1.1.
[b] If connector shows no signs of damage, go to step 5.
5. Measure the resistance between pin 10 and pins 1 on the valve cover side of the Front Injector Harness. If using J-48671–10, measure between injector #1 pins 1 and 2.
[a] If the resistance is greater than 3 Ω, replace the under valve cover injector harness.Refer to section 59.1.1.1.
[b] If the resistance is less than 3 Ω, go to step 6.
6. Disconnect the MCM 120–pin connector.
7. Measure the resistance between pin 11of the MCM 120–pin connector and pin 10 of the
Front Injector Harness 12–pin connector. See Figure 59-1.
[a] If the resistance is less than 3 Ω, go to step 8.
[b] If the resistance is greater than 3 Ω, repair the open between pin 11 of the MCM 120–pin connector and pin 10 of the Front Injector Harness 12–pin connector.
Refer to section 59.1.1.1.
8. Disconnect the negative battery cable.
9. Measure the resistance between the positive battery post and pin 11of the MCM 120–pin
connector.
[a] If the resistance is greater than 3 Ω, contact the Detroit Diesel Customer Support Center at 313–592–5800 for MCM replacement authorization.
[b] If the resistance is less than 3 Ω, repair the short to power between battery positive
and pin 11of the MCM 120–pin connector. See Figure 59-1. Refer to section 59.1.1.1.

10. Turn the ignition OFF.
11. Disconnect the Front Injector Harness 12–pin connector.
12. Measure the resistance between pin 10 and pin 1 on the valve cover side of the injector
harness.
[a] If the resistance is greater than 3 Ω, go to step 13.
[b] If the resistance is less than 3 Ω, go to step 18.
13. Remove the upper valve cover.
14. Disconnect injector #1.
15. Measure the resistance between pin 10 and pin 1 on the valve cover side of the injector
harness and pin 1 of the injector #1 harness connector.
[a] If the resistance is greater than 3 Ω, replace the under valve cover injector harness.
Refer to section 59.1.1.1.
[b] If the resistance is less than 3 Ω, go to step 16.
16. Measure the resistance between pin 1 on the valve cover side of the injector harness and pin 2 of the injector #1 harness connector.
[a] If the resistance is less than 3 Ω, go to step 17.
[b] If the resistance is greater than 3 Ω, replace the under valve cover injector harness.
Refer to section 59.1.1.1.
17. Measure the resistance between pin 1 on the valve cover side of the injector harness
and ground.
[a] If the resistance is less than 3 Ω, replace the under valve cover injector harness.
Refer to section 59.1.1.1.
[b] If the resistance is greater than 3 Ω, replace injector #1. Refer to section 59.1.1.1.
18. Measure the resistance between pin 1 on the valve cover side of the injector harness and
ground. If using J-48671–10, measure between injector #1 pin 1 and ground.
[a] If the resistance is less than 3 Ω, go to step 19.
[b] If the resistance is greater than 3 Ω, go to step 22.
19. Remove the upper valve cover.
20. Disconnect the injector #1 connector.
21. Measure the resistance between pin 1 on the valve cover side of the injector harness and
ground. If using J-48671–10, measure between injector #1 pin 1 and ground.
[a] If the resistance is less than 3 Ω, replace the under valve cover injector harness.
Refer to section 59.1.1.1.
[b] If the resistance is greater than 3 Ω, replace injector #1. Refer to section 59.1.1.1.
22. Disconnect the MCM
23. Measure the resistance between pin 1 on the MCM side of the injector harness connector
and pin 26 of the 120–pin MCM connector.
[a] If the resistance is greater than 3 Ω, repair the open circuit between pin 1 of the
Front Injector Harness 12–pin connector and pin 26 of the 120–pin MCM connector.
Refer to section 59.1.1.1.
[b] If the resistance is less than 3 Ω, repair the short to ground between pin 1 of the
Front Injector Harness 12–pin connector and pin 26 of the 120–pin MCM connector.
Refer to section 59.1.1.1.

59.1.1.1
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.
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. If assistance is required, call the Detroit Diesel
Customer Support Center at 313–592–5800.

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