Fuel and air

P022B — Charge Air Cooler Bypass Control "A" Circuit Low

Severity: medium Drive with care, to a shop

What P022B means

The engine control module operates an actuator that routes air around or through the charge air cooler (intercooler) and monitors the voltage in that control circuit. P022B sets when the voltage in circuit "A" is lower than expected. The usual causes are wiring shorted to ground, a poor connection, or a failing actuator.

Symptoms

  • Check Engine Light on
  • Reduced power or hesitation under load
  • Limp mode or reduced boost
  • Poor fuel economy
  • Uneven acceleration

Possible causes

  1. Damaged wiring or a short to ground in the bypass control circuit
  2. Corroded or loose connector at the actuator
  3. Failed charge air cooler bypass actuator
  4. Blown fuse or faulty relay feeding the circuit
  5. Internal ECM fault (uncommon)

How to diagnose

  1. Scan for codes and freeze frame data, clear the code and see if it returns
  2. Inspect the actuator harness and connector for chafing, oil, moisture and corrosion
  3. Check the fuse and relay for the circuit using the vehicle wiring diagram
  4. Measure supply voltage and circuit resistance, and test for a short to ground
  5. Command the actuator with a scan tool and see if it moves
  6. Check the bypass flap for sticking or carbon buildup
  7. If wiring and actuator test good, check the ECM and for software updates

Common fixes

  • Repair damaged wiring and clean or replace the connector
  • Replace the fuse or relay
  • Replace the bypass actuator or valve assembly
  • Reprogram or replace the ECM if confirmed faulty

Questions and answers

What does P022B mean?

It means the ECM detected low voltage in charge air cooler bypass control circuit "A". The actuator circuit is not behaving normally, so intake air temperature control may be off.

Can I drive with a P022B code?

Usually yes, for a short time and under light load. The engine may reduce boost and power, so get it diagnosed soon.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.