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. Its position sensor is usually built into the actuator, with a 5 V reference and a ratiometric signal. P024D is the plausibility fault: the signal is electrically valid but does not match the commanded position or the end stops. Bypass control is then switched off and the flap stays in its rest position. 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.
Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
Symptoms
- Check engine light on
- Depending on the rest position: longer warm-up or higher charge air temperature with slight loss of power
- Often nothing noticeable while driving
Most likely causes
- Flap or linkage misadjusted or sticking
- Sensor drifting or track worn
- Contact resistance at the connector
- End stops not learned after replacement
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P024D means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 2: Fuel injection
- 4D: Specific fault in that system
Frequently asked questions
Can I keep driving with code P024D?
Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
What causes code P024D?
The most common causes are: flap or linkage misadjusted or sticking; sensor drifting or track worn; contact resistance at the connector.
Related codes
- P024CCharge Air Cooler Bypass Position Sensor A Circuit
- P024ECharge Air Cooler Bypass Position Sensor A Circuit Low
- P024FCharge Air Cooler Bypass Position Sensor A Circuit High
- P024ACharge Air Cooler Bypass Control A Range/Performance
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.