OBD-II code · Powertrain (generic)
P04A6 Exhaust Pressure Control Valve B Position Sensor Circuit
A circuit fault is detected on the position sensor of exhaust pressure control valve B. Without valid position feedback the ECU cannot run closed-loop control of the valve and falls back to a default substitute.
Is it safe to drive with P04A6?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in sensor signal, supply or ground
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.8–2 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Pressure Position Sensor B
Related codes
- P04A3Exhaust Pressure Control Valve B Intermittent
- P04A4Exhaust Pressure Control Valve B Stuck Open
- P04A5Exhaust Pressure Control Valve B Stuck Closed
- P04A7Exhaust Pressure Control Valve B Position Sensor Circuit Range or Performance
- P04A8Exhaust Pressure Control Valve B Position Sensor Circuit Low
- P04A9Exhaust Pressure Control Valve B Position Sensor Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.