What it means
Exhaust pressure sensor B above upper plausibility — open signal or short to B+. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Exhaust pressure sensor B measures exhaust pressure for DPF monitoring or turbo control, depending on the vehicle. The control module sets P047D when the circuit signal is above its expected upper range, which can happen with an open signal wire or a short to battery voltage.
Common causes
Most likely first.
- Open signal line
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Possible reduced engine power
- Possible increased exhaust smoke
- Possible reduced fuel economy
How to diagnose it
- Save freeze-frame data and check live sensor B readings to confirm that the signal is high and note when it occurs.
- Inspect sensor B’s connector and harness for loose or corroded terminals, an open signal wire, or insulation contacting a power source.
- Test the sensor B signal circuit for an open or short to voltage using the wiring diagram and manufacturer’s procedure.
- Check connector terminal fit and circuit continuity, then verify sensor power and ground as specified by the manufacturer.
- Test sensor B against the manufacturer’s specification after confirming the circuit and pressure passage are intact.
Common fixes
- Reconnect or repair a loose or corroded sensor B connector.
- Repair an open sensor B signal wire.
- Repair wiring shorted to battery voltage and secure the harness.
- Replace sensor B if its output remains high with a verified circuit.
Can I keep driving?
Limit driving to necessary, gentle trips and avoid towing or hard acceleration. Incorrect pressure data may interfere with DPF or turbo control and can lead to smoke or reduced power.
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.