P024BCharge Air Cooler Bypass Control A Stuck
- 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
- The charge air cooler bypass is a flap or valve that routes compressed air around the charge air cooler, so the engine and exhaust warm up faster after a cold start; when warm it closes or opens partly to control intake air temperature. It is driven by an electric motor with a built-in position sensor or by a solenoid and vacuum can. P024B means the bypass flap does not move at all despite being commanded – the position signal stands still or the air temperature shows no reaction. Bosch's patent describes exactly the case of a valve stuck closed or a blocked bypass, which raises emissions during warm-up. Stuck open, the charge air gets hotter and power drops; stuck closed, warm-up takes longer. No manufacturer document using this code was found – GM and Ford do not use the bypass codes; the description rests on CARB's component monitoring requirement and a Bosch patent on the bypass valve.
- What you may notice
- Check engine light on
- Stuck open: higher charge air temperature, loss of power
- Stuck closed: longer warm-up
- Likely causes
- LikelyFlap seized or coked
- PossibleActuator faulty (gear, motor)
- RareVacuum supply missing (pneumatic type)
- RarePosition sensor reading constant
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €80 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.