SHAFT-DRIVE 8D3744 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the relay for the Electric Fuel Lift Pump (EFLP). Use this procedure if there is a suspected electrical fault with the EFLP.This procedure covers the following diagnostic codes:
Table 1
Diagnostic Trouble Codes for the Circuit for the EFLP Relay
J1939 Code Description Notes
1075-5 Engine Electric Lift Pump for Engine Fuel supply: Current Below Normal The Electronic Control Module (ECM) detects the following conditions:
There are no active 168 diagnostic codes.
The ECM is not attempting to power the relay.
The ECM has been powered for at least 2 seconds.
There is a low current condition in the EFLP relay circuit for more than 2 seconds.
The warning light will come on. The diagnostic code will be logged.
The ECM is unable to activate the relay for the EFLP. The EFLP will not operate or the EFLP will operate all the time. The engine will not operate.
1075-6 Engine Electric Lift Pump for Engine Fuel supply: Current Above Normal The ECM detects the following conditions:
There are no active 168 diagnostic codes.
The ECM is attempting to power the relay.
The ECM has been powered for at least 2 seconds.
There is a high current condition in the EFLP relay circuit for more than 2 seconds.
The warning light will come on. The diagnostic code will be logged.
The ECM is unable to activate the relay for the EFLP. The EFLP will not operate or the EFLP will operate all the time. The engine will not operate.
The ECM will continue to attempt to activate the relay. If the current is OK for 6 seconds, then the diagnostic code will be cleared. The following background information is related to this procedure:The EFLP is used in order to provide positive fuel pressure to the high-pressure fuel pump. When the keyswitch is turned to the ON position, the ECM will activate the relay for the EFLP. If the engine is not running, the ECM will deactivate the relay for the EFLP after 2 minutes.
Illustration 1 g02358896
Typical schematic for the Electric Fuel Lift Pump (EFLP)
Illustration 2 g02138993
View of the pin location on the P1 connector for the EFLP
(21) Relay for the EFLP Test Step 1. Inspect Electrical Connectors and Wiring
Check that the fuses are not blown.
Check the harness for abrasion and pinch points from the Electric Fuel Lift Pump (EFLP) back to the ECM. Check the harness for abrasion and pinch points from the EFLP back to the battery.
Inspect the terminals on the EFLP relay and then inspect the harness connector for the relay. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Inspect the connector for the EFLP. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the EFLP.
Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in). Results:
All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. The fuses are not blown - Proceed