P024B: Charge Air Cooler Bypass Control A Stuck

What it means

The control module monitors charge air cooler bypass control A and sets this code when the bypass does not move as commanded. The fault indicates the bypass is stuck, but the code alone does not identify why.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

The charge air cooler bypass valve directs intake air through or around the cooler. The control module compares the commanded position with movement or position feedback and sets P024B when bypass control A does not move as commanded; the code does not identify whether the valve, actuator, wiring, or feedback is at fault.

Common causes

Most likely first.

1. Bypass valve binding or stuck
2. Actuator failure
3. Damaged wiring or connector
4. Position feedback fault

Symptoms

• Check-engine light on
• Reduced engine power or acceleration
• Poor turbo response
• Reduced fuel economy

How to diagnose it

1. Use freeze-frame data and scan-tool bypass command and position data, if available, to confirm when control A stopped responding.
2. Inspect bypass valve A, its linkage, and actuator for binding, obstruction, disconnection, or visible damage.
3. Check the actuator and position-feedback connector and wiring for corrosion, loose pins, or harness damage.
4. Command bypass valve A through its operating range with a suitable scan tool, if supported, and see whether movement and feedback match.
5. Test the actuator, feedback circuit, and valve movement against the manufacturer’s specification to isolate the cause.

Common fixes

• Clear debris or correct binding that prevents bypass valve A from moving.
• Reconnect or repair damaged wiring or connector terminals at the bypass actuator or position sensor.
• Replace the failed actuator if it cannot move bypass valve A.
• Repair the position-feedback circuit or replace its sensor if testing confirms a fault.

Can I keep driving?

Use gentle acceleration and avoid towing because the engine may have reduced power or poor turbo response. If limp mode or severe power loss occurs, stop when safe rather than continuing in traffic.