Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, Checking

General Description

The Engine Control Module -J623- tells the Fuel Pump Control Module -J538- the demand needed for fuel volume and pressure and activates the Fuel Delivery Unit -GX1-. The Fuel Delivery Unit -GX1- transfers fuel to the rest of the fuel system, where it is monitored by the Engine Control Module -J623- through sensors, and controlled through regulators and/or metering valve s.

Special Tools And Workshop Equipment Required

Multimeter.
Wiring Diagram.
Scan Tool.

Test Requirements

Fuses OK.
Battery voltage OK.
Switch OFF all electrical and electronic accessories.
Vehicles with Auto. Transmission, ensure Selector Lever position is in "P".
Vehicles with Man. Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
Observe all safety precautions: .
View clean working conditions: .

Test Procedure

NOTE:

When the door is opened or the Ignition is turned to the ON position the fuel pump is activated for 2 seconds to build up the pressure in the fuel system.

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers concern. Refer to . -- Was Complaint verified?	-- YES: GO TO: Step 2 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 2 . -- NO: GATHER more information from customer about the complaint.
2	IGNITION: ON. LISTEN: Fuel Delivery Unit -GX1- should be heard running for 2 sec. SPECIFIED VALUE: Transfer Fuel Pump ON for 2 sec. IGNITION: OFF. -- Was Value obtained?	-- YES: CONDITION: May be intermittent. PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 7 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 7 . -- NO: GO TO: Step 3 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 3 .
3	DISCONNECT: Fuel Pump Control Module -J538- harness connector. IGNITION: ON. CHECK: Fuel Pump Control Module -J538- harness connector terminal 3 to 4 for voltage. SPECIFIED VALUE: Battery voltage. IGNITION: OFF. -- Was Value obtained?	-- YES: GO TO: Step 4 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 4 . -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. REPLACE: Any open fuses. GO TO: Step 7 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 7 .
4	RECONNECT: Fuel Pump Control Module -J538- harness connector. DISCONNECT: Fuel Delivery Unit -GX1- harness connector. CRANK: Engine. CHECK: Fuel Delivery Unit -GX1- harness connector terminals 1 to 2 for voltage while engine is cranking. SPECIFIED VALUE: 7 - 11 V. IGNITION: OFF. -- Was Value obtained?	-- YES: REPLACE: Fuel Delivery Unit -GX1-, Refer to appropriate service information. GO TO: Step 7 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 7 . -- NO: GO TO: Step 5 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 5 .
5	DISCONNECT: Fuel Pump Control Module -J538- harness connector. CHECK: Fuel Delivery Unit -GX1- harness connector terminal 1 to the Fuel Pump Control Module -J538- harness connector terminal 1 for resistance. CHECK: Fuel Delivery Unit -GX1- harness connector terminal 2 to the Fuel Pump Control Module -J538- harness connector terminal 2 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: GO TO: Step 6 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 6 . -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 7 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 7 .
6	REMOVE: Engine Control Module -J623-. Refer to appropriate service information. CHECK: Fuel Pump Control Module -J538- harness connector terminal 5 to the Engine Control Module -J623- harness connector T91 / 9 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Was Value obtained?	-- YES: REPLACE: Fuel Pump Control Module -J538-. Refer to appropriate service information. GO TO: Step 7 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 7 . NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 7 Fuel Pump Control Module -J538- /Fuel Delivery Unit -GX1-, CHECKING - 7 .
7	Final Procedure Perform a road test to verify repair. Do any DTC's return:	-- YES: CHECK: Engine Control Module -J623- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Engine Control Module -J623-. Refer to appropriate service information. Clear the DTC's. Refer to . Repair is complete. Generate Readiness Code. Refer to . Return vehicle to Customer. -- NO: Perform the diagnostic procedure for any DTC's. If no DTC's return the repair is complete. Return vehicle to customer.