P022B–P022E Charge Air Cooler Bypass Control A Circuit Low
The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.
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 |
|---|---|---|
P022B | Charge Air Cooler Bypass Control A Circuit Low | Investigate soon |
P022E | Charge Air Cooler Bypass Control B Circuit Low | Investigate soon |
The definition
P022B: Charge Air Cooler Bypass Control A Circuit Low.
P022B 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:
- Unplug the sensor. If the reading jumps to full scale, the wiring is fine and the sensor has failed low.
- Check the sensor's 5V supply and its earth before condemning the sensor itself.
What actually causes this on a VAG
Same charge air cooler bypass control circuit, opposite electrical fault: the ECU sees the control wire pulled down to earth when it should not be. That means a short to earth in the wiring, damp bridging the connector, or an actuator that has failed shorted internally. The ECU switches its output off to protect itself. In most installations the bypass then reverts to leaving the charge air cooled normally and the car drives on with just the warning light showing - worth confirming for your engine rather than assuming. As with the open-circuit version, establish first whether your engine's bypass is an air-side flap near the intercooler or a coolant-side valve under the bonnet, because that decides where you are looking and what conditions the connector lives in.
Most likely causes, in order
- Water, salt or corrosion in the connector. Damp across the pins looks exactly like a short. This is the first suspect where the actuator is an air-side flap down at the intercooler, sitting in road spray - though a heat-aged or corroded plug will do the same thing anywhere under the bonnet. Unplug it and look for standing water, green deposits or salty crust, dry and clean it properly, then clear the code and see whether it stays away through a few wet days.
- Wiring shorted to earth. A rub-through where the loom crosses a bracket, a charge pipe or a body edge. Look for a worn shiny patch, and pay close attention to anywhere the loom has been re-routed, re-taped or cable-tied after previous work - a wire pinched during a front-end repair is a classic.
- The actuator has failed shorted internally. Perfectly possible, but it looks identical to a harness short from the ECU's point of view, which is why the unplug test below should come before any purchase.
Worth knowing: Free, decisive test: unplug the actuator, clear the code and run the engine. If the fault changes to open circuit or 'circuit high', the harness is healthy and the actuator is the fault. If it still reports 'low' with nothing plugged in, the short is in the wiring and a new valve will change absolutely nothing.
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 P022B mean?
P022B means Charge Air Cooler Bypass Control A Circuit Low. The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.
Can I drive with P022B?
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.