P024D: Charge Air Cooler Bypass Position Sensor A Circuit Range/Performance

What does P024D mean?

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.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

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

Common causes

• High Flap or linkage misadjusted or sticking
• Medium Sensor drifting or track worn
• Medium Contact resistance at the connector
• Low End stops not learned after replacement

Likelihood is a general estimate across vehicles; your make and model may differ.