P047D
Exhaust Pressure Sensor B Circuit High
Exhaust / emissions control
Generic OBD-II
Medium
What it means
P047D means the ECM has detected an abnormally high signal from exhaust pressure sensor "B", a second sensor monitoring exhaust back-pressure in the EGR or diesel aftertreatment system. The engine still runs, but the false-high reading can trigger reduced power and interfere with soot-filter operation, so it should be diagnosed rather than ignored.
Medium
Can I keep driving? Usually drivable, but the engine may enter reduced-power mode and diesel exhaust-aftertreatment functions can be disrupted, so repair it soon.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or limp mode (common on diesels)
- Decreased fuel efficiency
- Rough running under load
Common causes
Most likely first
- Faulty exhaust back-pressure sensor 'B'Likely
- Signal wire shorted high or an open in the circuitCommon
- Poor or corroded connection at the sensorCommon
- Blocked or damaged sensor pressure tube (soot/carbon)Less often
- Rarely, a failed ECMLess often
How to diagnose & fix
Work through it in order
- Inspect the 'B' exhaust pressure sensor and its pressure tube for soot blockage, cracks, or a loose fitting.
- Check the connector and wiring for a short-to-voltage or open on the signal circuit.
- Compare the sensor reading to known pressure with a scan tool; replace the sensor if it reads stuck high.
- Clear any blockage in the sensor port or tube, then clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P047D?+
For short trips usually, but the ECM may cut power and, on diesels, block DPF regeneration, so don't put off the repair.
Can I just clear P047D?+
The code returns once the high signal is read again unless the sensor, wiring, or blocked tube is fixed.
Related codes
Often seen with P047D
Read & clear P047D yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX