P022C

What it means

P022C is the generic SAE J2012 code for Charge Air Cooler Bypass Control 'A' Circuit High. The engine control unit monitors the electrical circuit that drives the charge air cooler bypass valve or actuator. It has detected a voltage higher than expected, or a signal that does not match the commanded state, so it has set the code. The exact layout of the bypass system depends on the vehicle and engine, and not every engine has one.

Symptoms

• Engine warning light on
• Reduced power or the engine going into limp mode
• Poor or hesitant acceleration under boost
• Higher than normal intake air temperatures
• Possible knock or pinking under load
• Occasional rough running or inconsistent boost

Possible causes

• Wiring fault in the bypass control circuit, such as a short to voltage, or chafed or damaged harnesslikely
• Corroded, loose or damaged connector at the bypass valve or actuatorlikely
• Faulty bypass valve or actuator with an internal electrical faultlikely
• Valve or flap seized or stuck mechanically by carbon, oil residue or debris, so the commanded and actual positions disagreepossible
• Fault in the power supply or earth to the actuator, such as a blown fuse or relay where fittedpossible
• Faulty engine control unit driver circuit, or outdated software where the manufacturer has a known fixrare

How to diagnose

1. Read all stored and pending codes and note freeze frame data such as engine load, intake air temperature and coolant temperature
2. Check for other boost, intake temperature or actuator related codes that might point to a shared cause
3. Inspect the bypass valve wiring and connector for chafing, heat damage, water ingress, corrosion and bent or pushed-back pins
4. Check the relevant fuses and relays and the power and earth supply at the actuator, using the manufacturer's wiring diagram for your model
5. Measure the control signal voltage at the connector with the ignition on and compare it with the specified values for the engine
6. Command the bypass valve with a suitable diagnostic tool, then check that it moves smoothly through its full range and the position feedback follows
7. Inspect the valve and the related pipework by eye for carbon build-up, oil contamination, sticking or physical damage
8. Check for any manufacturer software updates or technical service bulletins relating to this code on your engine

How to fix

• Repair or replace damaged wiring, and correct any short to voltage found in the control circuit
• Clean, repair or replace corroded or damaged connectors and terminals
• Replace the bypass valve or actuator if it fails electrical or movement tests
• Clean or free a sticking valve where the manufacturer permits it, and fix the cause of any oil or carbon contamination
• Replace a failed fuse or relay after finding out why it failed
• Update the engine control unit software if an outdated calibration is a known cause for that model, or replace the unit if the driver circuit is confirmed faulty

Can I keep driving?

Nearby codes

• P022BGenericCharge Air Cooler Bypass Control A Circuit Low
• P022DGenericCharge Air Cooler Bypass Control B Circuit /Open