P0475 Exhaust Pressure Control Valve Fail

P0475 Exhaust Pressure Control Valve Audi R8

Audi R8 – P0475 Exhaust Pressure Control Valve P047500

Description P0475

The P0475 means that there is something wrong with Audi Exhaust Door Valve or its Control Circuit.

Causes the P0475

There may be more than one cause for the P0475 code :

Faulty Exhaust Door Valve N321.
The Exhaust Door Valve N321 is shorted out or open.
Poor electrical connection on your Exhaust Door Valve N321.
Faulty PCM.

The symptoms of the P0475

Check Engine Warning light may come on to show that having issues with Exhaust Door Valve N321 or its Control Circuit.

How to diagnose the P0475

You can detect problems with either the Exhaust Door Valve N321 (EBP) Device or the tube between the exhaust manifold and the EBP sensor with an exhaust back pressure step test.

This is when the Engine Control Module (ECM) commands and then measures a particular preprogrammed pressure. It then measures time for pressure decay during your engine running test. If the ECM detects an Exhaust Door Valve N321, Intake Air Temperature or Engine Oil Temperature sensor fault, the ECM will disable the Exhaust Door Valve N321 regulator. This is how you know that you probably have an Exhaust Door Valve N321 malfunction and just what exactly is malfunctioning.

P0475 code checking proceduce

Use scan tool to clear the diagnostic trouble codes from memory. If P0475 it does not return, then faulty can because of the connections . If the code returns, continue to test the solenoid and its circuits.

General Description

The Exhaust Door Valve 1 -N321- is controlled by the Engine/Motor Control Module -J623- .

Multimeter.
Wiring Diagram.
Scan Tool.

Test requirements

Fuses OK.
Battery voltage OK.
Switch OFF all electrical and electronic accessories.
Vehicles with automatic transmission, ensure the selector lever position is in “P”.
Vehicles with manual transmission, ensure the shifter lever position is in “N” with the parking brake applied.

First disconnect the harness going to the Exhaust Door Valve. With a Digital Volt OhmMeter, connect one lead of the meter to one of the solenoid terminals. Then connect the other meter lead to the other solenoid terminal. SPECIFIED VALUE: 5 – 30 Ω.

Next you will need to determine have 12V on ther Exhaust Door Valve power supply circuit. Make sure that your ignition is on. If you do not see 12 volts to the harness connector terminal 1, or if there is 12 volts when the ignition is off, you will need to :

PERFORM: Visual Inspection of wiring and component.
CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals.

If everything is ok now, continue next step :

REMOVE: Engine/Motor Control Module -J623- . Refer to appropriate repair manual.
CHECK: Exhaust Door Valve 1 -N321- harness connector terminal 2 to the Engine/Motor Control Module -J623- harness connector T91a / 73 for resistance.
SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω).

TIP: The Exhaust Door Valve 1 -N321- may fail under loaded operation; please swap a known good Exhaust Door Valve 1 -N321- prior to continuing to the next step.

Final Procedure:

Perform a road test to verify repair.
If the original DTC returns : CHECK: Engine/Motor Control Module -J623- harness connector for any damaged, pushed-out pins, If all electrical connections are OK then REPLACE: Engine/Motor Control Module -J623- . Refer to appropriate repair manual.