Charge Air Pressure Sensor -G31-, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Engine Control Module (ECM) - J623- fuses OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• On vehicles with automatic transmission, selector lever in 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 Engine Control Module (ECM) -J623-, REPLACING .

Start diagnosis 

-- Remove the engine cover with air filter. Refer to 2.0 Liter 4-Cyl. 4V Turbo Fuel Injection & Ignition, Engine Code(s): BWA. Repair Group 24.

Test sequence 

-- Disconnect the Charge Air Pressure Sensor -G31- electrical harness connector -1-.

Fig 1: Charge Air Pressure Sensor G31

Courtesy of AUDI OF AMERICA, LLC

-- Start engine and let it run at idle.

-- Using a multimeter, check the Charge Air Pressure Sensor -G31- electrical harness connector terminals 1 to 3 for voltage.

Fig 2: 4-Pin Electrical Harness Connector & Terminals

Courtesy of AUDI OF AMERICA, LLC

Specified value: min. 4.5 V

-- Switch the ignition off.

If the specification was not obtained:

Checking wiring 

If the manufacturers test box is being used. Perform the following step.

-- Install the test box. Refer to 2.0 Liter 4-Cyl. 4V Turbo Fuel Injection & Ignition, Engine Code(s): BWA. Repair Group 24.

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

-- Remove the Engine Control Module (ECM) -J623-. Refer to Engine Control Module (ECM) -J623-, REPLACING .

-- Using a multimeter, check the Charge Air Pressure Sensor -G31- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T94 terminals for resistance.

Fig 3: 4-Pin Electrical Harness Connector & Terminals

Courtesy of AUDI OF AMERICA, LLC

Specified value: 1.5 Ω max.

If the specification was not obtained:

-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

-- If necessary, repair the faulty wiring connection.

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

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

-- Replace the Charge Air Pressure Sensor -G31-.

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to READINESS CODE .

-- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was not OK:

-- Replace the Engine Control Module (ECM) -J623-. Refer to Engine Control Module (ECM) -J623-, REPLACING .

-- Assembly is performed in the reverse of the removal.

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 .

End of diagnosis