Fuel Tank Leak Detection Control Module, Checking

Fuel Tank Leak Detection Control Module, Checking

Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.

For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.

The following procedure is used to diagnose the Fuel Tank Lead Detection Control Module (J909) which is controlled by Engine Control Module (J623).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Engine Component Power Supply Relay (J757) OK.

• The Fuse (SF2) OK.

• The fuel filter OK.

• The parking brake engaged.

• The battery voltage at least 12.5 V.

• The selector lever of automatic transmission in position "P" or "N".

• All electrical consumers switched off.

• A/C switched off.

• The fuel tank at least 1/4 filled.

• The ignition switched off.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.

Start diagnosis

- Remove the left rear underbody protective cover.

- Using a Multimeter, Check the Fuel Tank Lead Detection Control Module (J909) electrical harness connector terminals 1 to 3 for voltage.






- Switch the ignition ON.






Specified value: Battery voltage

- Switch the ignition OFF.

- Continue test according to the following table:






Checking wiring

- Remove the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

- Using a Multimeter, Check the Fuel Tank Lead Detection Control Module (J909) electrical harness connector to the Motronic Engine Control Module (ECM) electrical harness connector T94 for an open circuit.

- also check the wiring from the Fuel Tank Lead Detection Control Module (J909) electrical harness connector terminal 1 to the Fuse 2 (on fuse panel F) (SF 2) for an open circuit or a short circuit to Ground (GND).











Specified value: 1.5 ohms Max.

If the specified value was Not obtained:

- Check the wiring connection for an open circuit or short circuit.

- Check the wiring connection for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

- Repair the circuit and replace any open fuses.

- Go to Final procedures

If the specified value was obtained:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

- Go to Final procedures

Checking wiring

- Remove the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

- Using a Multimeter, Check the Fuel Tank Lead Detection Control Module (J909) electrical harness connector to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T94 for an open circuit.











Specified value: 1.5 ohms Max.

If the specified value was Not obtained:

- Check the wiring connection for an open circuit or short circuit.

- Check the wiring connection for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

- Go to Final procedures

If the specified value was obtained:

- Replace the Fuel Tank Lead Detection Control Module (J909). Refer to appropriate service manual.

Final procedures

- Reinstall the left rear underbody protective cover.

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.