Low Fuel Pressure Sensor, Checking

Observe all safety precautions: SAFETY PRECAUTIONS 

View 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.

Special tools and workshop equipment required 

• multimeter.
• Wiring diagram.

Test requirements 

• The Fuel Pump (FP) Control Module -J538- OK.
• The Motronic Engine Control Module (ECM) - J623- fuses OK.
• The fuel filter OK.
• The battery voltage at least 12.5 V.
• All electrical consumers switched off (radiator fan must NOT run during test).
• 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 

Start diagnosis 

-- Remove the engine cover with air filter. Refer to appropriate service information.

Checking voltage

-- Disconnect the Low Fuel Pressure Sensor -G410- electrical harness connector -2-.

-- Switch the ignition on.

-- Using a multimeter, check the Low Fuel Pressure Sensor -G410- electrical harness connector for voltage.

Low Fuel Pressure Sensor -G410- electrical harness connector terminals	Specified value
1 to Battery positive (+)	Battery voltage
2 to Ground (GND)	Near 0 volts
3 to Ground (GND)	5 V

-- Switch the ignition off.

If the specified value was obtained:

-- Replace the Low Fuel Pressure Sensor -G410-. Refer to appropriate service information.

If the specified value was Not obtained:

Checking wiring 

If the manufacturers test box is being used, perform the following step.

-- Install the test box.

If the manufacturers test box is not being used, perform the following step.

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

-- Using a multimeter, check the Low Fuel Pressure Sensor -G410- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open circuit according to the wiring diagram.

Low Fuel Pressure Sensor -G410- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminals or test box socket
1	GND
2	40
3	29

Specified value: 1.5 Ω Max.

If the specified value was Not obtained:

-- Check the wiring for an open, high resistance, short to Battery (+) or Ground (GND).

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

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

-- Install the engine cover with air filter. Refer to appropriate service information.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .