OBD-II code · Powertrain (generic, extended)
P23A6 Exhaust Heat Exchanger Bypass Valve B Stuck Open
Bypass valve B is stuck in the open position - exhaust bypasses the heat exchanger continuously, slowing engine warm-up.
Is it safe to drive with P23A6?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve stuck open
- Less likelyCarbon or debris buildup preventing free movement
- Less likelyComponent wear with age - mechanical play
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1.5–4 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Bypass Valve B
Related codes
- P23A3Exhaust Heat Exchanger Bypass Valve B Control Circuit Low
- P23A4Exhaust Heat Exchanger Bypass Valve B Control Circuit High
- P23A5Exhaust Heat Exchanger Bypass Valve B Control Performance
- P23A7Exhaust Heat Exchanger Bypass Valve B Stuck Closed
- P23A8Exhaust Heat Exchanger Bypass Valve B Position Sensor Stop Performance
- P23A9Communication Fault Forced Engine Shutdown
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.