Fuel Quality 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 system wiring diagram.

Special tools and workshop equipment required 

• Multimeter
• Wiring diagram

Test requirements 

• The Motronic Engine Control Module (ECM) - J623- fuses OK.
  Fig 1: Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• 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.

-- Disconnect the Fuel Quality Sensor -G446- electrical harness connector.

Checking voltage 

-- Switch the ignition on.

-- Using a multimeter, Check the Fuel Quality Sensor -G446- electrical harness connector terminal 3 to engine ground for voltage.

Specified value: battery voltage.

-- Switch the ignition off.

If the specified value was not obtained:

-- Check the wiring connections for an open circuit.

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

-- If necessary, repair the faulty wiring connection.

If the specified value was 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 Fuel Quality Sensor -G446- electrical harness connector to the Motronic Engine Control Module (ECM) electrical harness connector T60 for an open circuit.

Fuel Quality Sensor -G446- electrical harness connector terminals	Motronic Engine Control Module (ECM) electrical harness connector T60 terminals or test box sockets
1	53
2	59

Specified value: 1.5 Ω Max.

If the specified value was not obtained:

-- Check the wiring for a short circuit to Battery (+), or an open circuit.

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

-- If necessary, repair the faulty wiring connection.

If no malfunction is found in the wiring and voltage supply was OK:

-- Replace the Fuel Quality Sensor -G446-. Refer to appropriate service information.

If no malfunction is found in the wiring and voltage supply was not OK:

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