Description
1. 1 37-13
Additions, Revisions, or Updates
2. SPN 2798/FMI 4 – EPA10 – GHG14
This diagnostic is typically Injector Needle Control Valve Cylinder 4, 5, 6 Shorted to Ground.
Table 1.
1. Disconnect the rear fuel injector harness 14-pin connector.
2. Inspect the rear fuel injector harness 14-pin connector for bent or spread pins; inspect the connector seal for damage (signs of water or oil intrusion).
a. If there is evidence of water or oil intrusion, bent or spread pins, repair as necessary.
b. If the connector shows no signs of damage, Go to step 3.
3. Measure the resistance between pin 1 on the rocker cover side of the rear fuel injector harness 14-pin connector and ground. If you are using J-48671–10, measure between fuel injector #4 pin 3 and ground.
a. If the resistance is less than 3 ohms, Go to step 4.
b. If the resistance is greater than 3 ohms, Go to step 11.
4. Remove the rocker cover. Refer to section “Removal of the Rocker Cover”.
5. Disconnect fuel injector #4.
6. Measure the resistance between pin 1 on the rocker cover side of the rear fuel injector harness 14-pin connector and ground. If you are using J-48671–10, measure between fuel injector #4 pin 3 and ground.
a. If the resistance is greater than 3 ohms, replace the #4 fuel injector. Refer to section “Removal of the Fuel
Injector – Three-Filter System”.
b. If the resistance is less than 3 ohms, Go to step 7.
7. Disconnect fuel injector #5.
8. Measure the resistance between pin 1 on the rocker cover side of the rear fuel injector harness 14-pin connector and ground. If you are using J-48671–10, measure between fuel injector #5 pin 3 and ground.
a. If the resistance is greater than 3 ohms, replace the #5 fuel injector. Refer to section “Removal of the Fuel
Injector – Three-Filter System”.
b. If the resistance is less than 3 ohms, Go to step 9.
9. Disconnect fuel injector #6.
10. Measure the resistance between pin 1 on the rocker cover side of the rear fuel injector harness 14-pin connector and ground. If you are using J-48671–10, measure between fuel injector #6 pin 3 and ground.
a. If the resistance is greater than 3 ohms, replace the #6 fuel injector. Refer to section “Removal of the Fuel
Injector – Three-Filter System”.
b. If the resistance is less than 3 ohms, replace the under valve cover fuel injector harness. Refer to section
“Removal of the Two-Piece Fuel Injector Wiring Harness – Three-Filter System”.
11. Disconnect the 120–pin Motor Control Module (MCM) connector.
12. Measure the resistance between pin 1 on the valve cover side of the rear fuel injector harness 14-pin connector and ground.
a. If the resistance is less than 3 ohms, repair the short to ground between pin 19 of the MCM 120–pin connector
and pin 1 of the rear fuel injector harness 14-pin connector.
b. If the resistance is greater than 3 ohms, Go to step 13.
13. Inspect the fuel injector harness for chafed or pinched wires. Is any wire chafed or pinched?
a. Yes; replace the fuel injector wiring harness and verify repair.
b. No; Go to step 14.
14. Install a test MCM using the extension harness and test drive the truck. Does the code come active?
a. Yes; call the DetroitTM Customer Support Center at (800) 445-1980.
b. No; replace MCM and verify repair.
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