P23A5Exhaust Heat Exchanger Exhaust Bypass Valve B Control Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Unlike the circuit codes, P23A5 judges the result: the module commanded valve B, the second exhaust bypass at the heat exchanger, but it does not see the response it expects, for example in position feedback or in how the exhaust-side coolant temperatures change. No manufacturer publishes P23A5. Ford's handling of valve A shows how such a check can mislead: for P237F on F-150, Explorer, Escape and Maverick full hybrids up to 2024, SSM 52543 first has the connectors of exhaust coolant temperature sensors 3 and 4 inspected for water or corrosion, and TSB 24-2173 cures false P237F on 2024 Mavericks with a PCM update. CARB requires a functional check of output components. Driving is usually unaffected; P23A6 and P23A7 name a flap stuck in one position.
- What you may notice
- Check engine light on
- Cabin heat slow to arrive in winter
- No effect on drivability
- Likely causes
- LikelyFlap of valve B sluggish from soot or corrosion
- PossibleExhaust coolant temperature sensor connector wet or corroded, distorting the plausibility check
- PossibleWorn actuator gearing or linkage
- RareOverly strict calibration, fixed by a software update
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.