P022A–P022D Charge Air Cooler Bypass Control A Circuit /Open
The ECU has logged a fault on P022A. The definition below is the exact wording the standard uses for this code.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P022A | Charge Air Cooler Bypass Control A Circuit /Open | Investigate soon |
P022D | Charge Air Cooler Bypass Control B Circuit /Open | Investigate soon |
The definition
P022A: Charge Air Cooler Bypass Control A Circuit /Open.
P022A is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
What actually causes this on a VAG
Some turbocharged engines can route pressurised intake air around the charge air cooler (the intercooler) instead of through it, so everything warms up faster and condensation does not form inside the cooler in cold, damp weather. The bypass is worked by an actuator the ECU controls - on some installations a flap in the air path, on water-cooled charge air systems a valve on the coolant side. Not every VAG turbo has one, and the two arrangements live in completely different places, so the first job is establishing what your engine actually has and where the actuator sits. Do that from the VAG-specific fault text and the wiring diagram for your engine code, not from a generic description. P022A covers this control circuit generally and an open circuit in particular: the ECU energised the output and got nothing back. In most installations the bypass then reverts to leaving the charge air cooled normally, so the car often drives with no obvious symptom beyond the warning light - which is an MOT failure in the UK. Confirm that rather than assuming it: if your engine's bypass rests in the wrong position, running it hard is not a good idea.
Most likely causes, in order
- Connector unplugged, unlatched or corroded. The cheapest thing to check and a very common answer on any actuator circuit. It is also the first connector to get left off after work in that area - an intercooler, radiator pack, coolant job or front bumper, depending on where your engine's actuator lives. Unplug it, check for green pins and a snapped latch, refit and make sure it clicks home. If the actuator is an air-side flap near the intercooler, expect road spray, salt and grit in the plug; if it is a coolant-side valve under the bonnet, expect heat-aged pins instead.
- Broken wire in the loom. The run passes hot pipes and parts that move with the engine. Chafe through to a break, or a pin pushed back out of the connector body, both read as open circuit. Follow the wire looking for worn insulation and pull gently on each wire at the back of the plug.
- The actuator has failed open circuit. The motor or solenoid winding has gone open internally. Suspect this once the plug and the wiring have both been physically checked - not merely glanced at. A resistance measurement across the actuator's own terminals, compared against the figure in the workshop data for your engine, settles it.
Worth knowing: If the light appeared straight after a service, an intercooler, coolant, radiator pack or front bumper job, check the connector before anything else. An open circuit on this valve is far more often a plug that was never clicked back on than a failed part, and that is a two-minute fix rather than a bill. And before ordering anything, confirm from the VAG fault text that your engine has this actuator at all - a generic P-code description is not proof that the part exists on your car.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P022A mean?
P022A means Charge Air Cooler Bypass Control A Circuit /Open. It is logged when the ECU sees this circuit outside its expected operating window.
Can I drive with P022A?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.