What it means
The PCM detected a high 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. P01FD sets when the control module detects Sensor B's circuit signal above its expected level, indicating a high electrical signal rather than proving a mechanical boost-control fault.
Common causes
Most likely first.
- Signal wire open
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
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
- Save freeze-frame data and compare Sensor B's live reading with Sensor A and other pressure readings, including with the engine off where appropriate.
- Inspect Sensor B's connector and harness for an open signal connection, loose pins, corrosion, or damaged insulation.
- Check for a supply wire pinched against a battery-positive or other power source.
- Test Sensor B signal, supply, and ground circuits for opens, shorts to power, or poor connections against the manufacturer's specification.
- If the circuit checks out, test Sensor B and the control module input using the manufacturer's procedure.
Common fixes
- Repair an open or damaged Sensor B signal wire.
- Repair a supply wire shorted to a power source.
- Clean and secure corroded or loose Sensor B connector terminals.
- Replace Sensor B if its signal remains high with the circuit verified.
Can I keep driving?
Avoid hard acceleration and towing until the high signal is diagnosed, since the control module may limit engine power or mismanage boost. Stop if severe power loss, smoke, or abnormal turbo noise occurs.
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.