Fuel Tank Pressure Sensor - G400-, Checking

General Description

The evaporative system integrity can be tested by applying a vacuum signal to the fuel tank in order to create a small vacuum. The Engine Control Module -J623- then monitors the ability of the system to maintain the vacuum through signals sent from the Fuel Tank Pressure Sensor -G400-. If the vacuum remains for a specified period of time, then there are no evaporative leaks detected, and a PASS is reported by the Engine Control Module -J623-. If there is a leak, the system either will not achieve a vacuum, nor maintain the vacuum.

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: SAFETY PRECAUTIONS .
View clean working conditions: CLEAN WORKING CONDITIONS .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to PRELIMINARY CHECK . -- Was Complaint verified?	-- YES: GO TO: Step 2. -- NO: GATHER more information from customer about the complaint.
2	DISCONNECT: Fuel Tank Pressure Sensor -G400- harness connector CHECK: Fuel Tank Pressure Sensor -G400- component connector terminals 1 to 3 for resistance. SPECIFIED VALUE: 18 - 30 Ω (± 5.0 Ω @ approx. 20° C) -- Was Value obtained?	-- YES: GO TO: Step 3. -- NO: REPLACE: Fuel Tank Pressure Sensor -G400-. Refer to appropriate Service Information. GO TO: Step 4.
3	REMOVE: Fuel Tank Leak Detection Control Module -J909-. Refer to appropriate Service Information. CHECK: Fuel Tank Pressure Sensor -G400- harness connector terminal 1 to Fuel Tank Leak Detection Control Module -J909- harness connector terminal 1 for resistance. CHECK: Fuel Tank Pressure Sensor -G400- harness connector terminal 3 to Fuel Tank Leak Detection Control Module -J909- harness connector terminal 5 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: TIP: The Fuel Tank Pressure Sensor -G400- may fail under loaded operation; please swap a known good Fuel Tank Pressure Sensor -G400- prior to continuing to the next step. GO TO: Step 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. GO TO: Step 4.
4	Final Procedure Perform a road test to verify repair. -- Does the original DTC 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 DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . Repair is complete. Generate Readiness Code. Refer to READINESS CODE . 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.