Exhaust Pressure Sensor B Circuit Low
What it means
P047C means the second exhaust pressure (back-pressure) sensor circuit is reading low. Like sensor A, this sensor helps the computer manage EGR and the particulate filter on diesels and some turbo engines. A low or lost signal can trigger reduced-power or limp mode to protect the engine, but the car still runs and starts.
Can I keep driving? Often reduced — the engine may enter limp mode with lower power; drive gently to get it diagnosed, but avoid towing or hard acceleration.
Real-world scan data
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or acceleration
- Engine may enter limp mode
- Decreased fuel efficiency
Common causes
Most likely first
- Faulty exhaust back-pressure sensor (sensor B)Likely
- Wiring shorted low or open in the sensor circuitCommon
- Corroded or loose sensor connectorCommon
- Clogged or damaged pressure sense tube to the sensorLess often
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the sensor B connector and wiring for shorts, opens, and corrosion.
- Check the sensor's pressure tube/port for soot clogging or damage and clean or replace as needed.
- Compare the sensor signal to spec; replace the sensor if it reads low or out of range.
- If wiring and sensor check out, have the ECM evaluated. Clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P047C?+
Can I just clear P047C?+
Related codes
Read & clear P047C yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.