What it means
The PCM detected a low signal from Turbocharger Outlet Pressure Sensor B. This indicates a circuit or sensor signal problem; it does not by itself identify a mechanical boost-control fault.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Turbocharger outlet pressure Sensor B measures pressure at the second designated turbo outlet sensing point or on the second turbo, depending on the system. P01FC sets when the control module sees Sensor B's circuit signal below its expected level, which points to a low electrical signal and does not alone establish a mechanical boost fault.
Common causes
Most likely first.
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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
- Capture freeze-frame data and check Sensor B's live reading with the ignition on and engine off, then compare it with Sensor A and other pressure readings.
- Inspect Sensor B's connector for corrosion, backed-out pins, or poor terminal contact, and check the harness for chafing that could short the signal to ground.
- Inspect the pressure hose or passage for blockage, leaks, or disconnection that could also affect the reported pressure.
- Test Sensor B signal, supply, and ground circuits for a short to ground or excessive connection resistance against the manufacturer's specification.
- If wiring and pressure plumbing are sound, test Sensor B and the module input using the manufacturer's procedure.
Common fixes
- Repair a signal wire shorted to ground or a chafed Sensor B harness.
- Clean, tighten, or repair corroded Sensor B connector terminals.
- Repair a blocked or leaking Sensor B pressure hose.
- Replace Sensor B if it produces a low signal despite correct circuit power and ground.
Can I keep driving?
Avoid hard acceleration and towing because the control module may limit power when it cannot trust Sensor B's low signal. Stop if severe power loss, smoke, or unusual turbo noise develops.
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.