Fuel Tank Leak Detection Control Module -J909 -, CHECKING

WARNING: This page is about a different car, the 2022 Volkswagen Atlas Cross Sport, 2021 Volkswagen Atlas Cross Sport, and 2020 Volkswagen Atlas Cross Sport. However, it is still accessible from the selected car via links, so may be relevant.

General Description

The system can test the evaporative system integrity by using natural vacuum after the engine is shut off. The Engine Control Module -J623- monitors the ability of the system to maintain vacuum through signals sent from the Fuel Tank Pressure Sensor -G400- and the Fuel Tank Leak Detection Control Module -J909-. If the vacuum remains for a specified period of time, then there are no evaporative leaks, and a PASS is reported by the Engine Control Module -J623-. If there is a leak, the system either will not achieve a vacuum, or a vacuum cannot be maintained. Usually a fault can only be detected after a cold start.

Special tools and workshop equipment required

Multimeter.
Wiring Diagram.
Scan Tool.
Hand Vacuum pump.
Evap Smoke Tester.

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 Manual Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
Observe all safety precautions. Refer to: SAFETY PRECAUTIONS .
View clean working conditions. Refer to: 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 Fuel Tank Leak Detection Control Module -J909 -, CHECKING - 2 . -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. REMOVE: Evaporative Canister. Refer to appropriate repair information. Plug or Cap off the Fuel Tank Leak Detection Control Module -J909 - hose going to the vent filter. CONNECT: Hand vacuum pump to the Fuel Tank Leak Detection Control Module -J909 - and apply 0.700 bar and see if the vacuum holds. -- Did the vacuum hold?	-- YES: GO TO: Step 3 Fuel Tank Leak Detection Control Module -J909 -, CHECKING - 3 . -- NO: REPLACE: Fuel Tank Leak Detection Control Module -J909 -. Refer to appropriate repair information. GO TO: Step 5 Fuel Tank Leak Detection Control Module -J909 -, CHECKING - 5 .
3	DISCONNECT: Fuel Tank Leak Detection Control Module -J909 - harness connector. IGNITION: ON. CHECK: Fuel Tank Leak Detection Control Module -J909 - harness connector terminal 4 to ground for voltage. IGNITION: OFF. SPECIFIED VALUE: Battery voltage. -- Was Value obtained?	-- YES: GO TO: Step 4 Fuel Tank Leak Detection Control Module -J909 -, 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. GO TO: Step 5 Fuel Tank Leak Detection Control Module -J909 -, CHECKING - 5 .
4	REMOVE: Engine Control Module - J623-. Refer to appropriate repair information. DISCONNECT: Fuel Tank Leak Detection Control Module -J909 -. Refer to appropriate repair information. CHECK: Fuel Tank Leak Detection Control Module -J909 - harness connector terminal 2 to the Engine Control Module - J623- harness connector T91 / 38 for resistance. CHECK: Fuel Tank Leak Detection Control Module -J909 - harness connector terminal 3 to the Engine Control Module - J623- harness connector T91 / 90 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: TIP: The Fuel Tank Leak Detection Control Module -J909 - may fail under loaded operation; please swap a known good Fuel Tank Leak Detection Control Module -J909 - prior to continuing to the next step. GO TO: Step 5 Fuel Tank Leak Detection Control Module -J909 -, CHECKING - 5 . -- 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 5 Fuel Tank Leak Detection Control Module -J909 -, CHECKING - 5 .
5	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 repair 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.