What it means
The PCM detected a high input in the Charge Air Cooler Bypass Control A circuit. The code identifies a circuit signal fault; the exact component depends on the vehicle design.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Charge-air-cooler bypass control A operates a bypass mechanism in the intake-air cooling system; its actuator and wiring arrangement vary by vehicle. P022C sets when the PCM detects an A-circuit input above its expected range, which may result from a short to battery voltage or a high-resistance connection.
Common causes
Most likely first.
- Wiring shorted to battery
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Reduced engine power or acceleration
- Poor turbo response
- Reduced fuel economy
How to diagnose it
- Record freeze-frame data and scan for related bypass, boost, or charge-air temperature codes to identify when the A input went high.
- Inspect the charge-air-cooler bypass control A connector for corrosion, loose terminals, or signs of overheating.
- Trace the A-circuit wiring for insulation damage or pinching where it could contact a battery-positive feed.
- Check scan-tool data for the A-control command and reported state, if those values are available for the vehicle.
- Measure the A circuit for an unintended voltage source or excessive connection resistance using the wiring diagram and manufacturer's specification.
Common fixes
- Clean and secure corroded or loose A-circuit terminals.
- Repair wiring pinched against a battery-positive source.
- Repair an A-circuit connector or wire with excessive resistance.
- Replace a confirmed faulty bypass actuator or control module.
Can I keep driving?
Poor turbo response or reduced power can make passing and merging unsafe, so avoid hard acceleration and towing until the fault is diagnosed. Stop somewhere safe if the power loss prevents you from keeping pace with traffic.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.