What it means
The turbocharger/supercharger bypass valve B reports a position sensor circuit high condition. Boost recirculation cannot be commanded reliably on this branch.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The position sensor on turbocharger or supercharger bypass valve B reports valve travel to the control module. P2C2C sets when the signal is above its expected range, which can happen if the signal wire contacts battery positive or the sensor circuit has an open that drives the reading high.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open position sensor
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
How to diagnose it
- Review freeze-frame and live valve B position data to confirm a high signal and note whether it stays high as the valve is commanded to move.
- Inspect the bypass valve B sensor connector and harness for a signal wire chafed against a power feed, corrosion or loose pins.
- Using the manufacturer's wiring information, check sensor supply and ground, then compare the signal voltage with the manufacturer's specification.
- With power isolated as specified, test the signal wire for a short to B+ and check continuity through the valve B sensor circuit.
- If the wiring passes, test the position sensor across the valve's travel and verify its response using the manufacturer's procedure.
Common fixes
- Repair a valve B signal wire shorted to B+ or damaged near a power feed.
- Clean and secure loose or corroded bypass valve B sensor terminals.
- Repair an open or poor connection in the sensor circuit if testing identifies one.
- Replace the valve B position sensor if the circuit is sound and its output remains out of range.
Can I keep driving?
If power is reduced or limp mode is active, keep speed and acceleration modest because boost recirculation may not be controlled reliably. Stop for severe misfire, heavy smoke or a flashing warning light to limit possible engine and catalytic-converter damage.
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.