OBD-II code · Powertrain (generic, extended)
P23A3 Exhaust Heat Exchanger Bypass Valve B Control Circuit Low
Same as P237D on bypass valve B. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P23A3?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyControl line shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–2.5 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Bypass Valve B
Related codes
- P237DExhaust Heat Exchanger Bypass Valve A Control Circuit Low
- P23A0O2 Sensor Exhaust Sample Error Bank 1 Sensor 2
- P23A1O2 Sensor Exhaust Sample Error Bank 2 Sensor 2
- P23A2Exhaust Heat Exchanger Bypass Valve B Control Circuit Open
- P23A4Exhaust Heat Exchanger Bypass Valve B Control Circuit High
- P23A5Exhaust Heat Exchanger Bypass Valve B Control Performance
- P23A6Exhaust Heat Exchanger Bypass Valve B Stuck Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.