What it means
The PCM detected a low 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, with the exact design depending on the vehicle. P022B sets when the PCM sees the A-circuit input below its expected range, which can happen with a short to ground or excessive resistance at a connection.
Common causes
Most likely first.
- Wiring shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 boost or bypass-control codes to see the operating conditions when the A input went low.
- Inspect the charge-air-cooler bypass control A connector and terminals for corrosion, moisture, or a poor fit.
- Trace the A-circuit harness for chafing or insulation worn through where it could contact ground.
- Use scan-tool data or an available actuator command to compare the commanded A-control state with its reported response.
- Test the A signal, supply, and ground circuits for a ground short or excessive resistance using the wiring diagram and manufacturer's specification.
Common fixes
- Clean and secure corroded A-circuit connector terminals.
- Repair chafed wiring that is shorting the A circuit to ground.
- Repair a damaged supply, ground, or signal connection in the A circuit.
- Replace a confirmed faulty A bypass actuator or control module.
Can I keep driving?
Reduced power or weak turbo response can make acceleration and merging difficult, so avoid towing and demanding drives until the cause is found. If power drops enough to impede traffic, pull over safely.
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.