P3138 - Airflow Control Valve: Control Difference (Solution)

Possible causes for air flow control, throttle body valve, control difference (P3138):
- Throttle body base setting not performed (see throttle body base setting).
- Wiring/electrical connections to the throttle body valve (throttle body) are faulty.
- Throttle body valve (throttle body) is mechanically faulty.

Possible solutions:
- Vacuum valve basic setting
- Check vacuum valve wiring/electrical connections (throttle valve)
- Replace throttle valve module/vacuum valve module.

Notes for 2.0 TFSI engines: Check and update engine control unit software if necessary, replace vacuum valve module/throttle valve module (V157) with an improved version.

Attention: In TFSI engines, fault code P3138 can be a consequence of incorrect air leaks in the intake system. When low lambda values or "system too lean" are detected in this direction, investigate further.