Powertrain, generic · Fuel and air metering (injector circuit)

P024B Charge Air Cooler Bypass Control A Stuck

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Flap seized or coked
Actuator faulty (gear, motor)
Vacuum supply missing (pneumatic type)
Position sensor reading constant

Symptoms

  • Check engine light on
  • Stuck open: higher charge air temperature, loss of power
  • Stuck closed: longer warm-up

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

charge air cooler bypass actuator aactuator wiringengine control modulecharge air cooler

Related codes

P024AP024DP022AP026AP0299

References: law.cornell.edu, patents.google.com.