P047A
Exhaust Pressure Sensor B Circuit
Auxiliary emissions control
Generic OBD-II
Medium
What it means
P047A means the ECM has detected a fault in the "B" exhaust pressure sensor circuit. This sensor measures exhaust back-pressure — common on diesel and turbocharged vehicles that use it to manage EGR and the diesel particulate filter. It's typically a sensor, wiring, or clogged-port issue. The car usually still runs, though it may enter reduced power until the fault is repaired.
Medium
Can I keep driving? Usually yes, but reduced — on many (often diesel) vehicles the ECM may limit power or block a DPF regeneration, so drive gently and have it diagnosed before soot builds up.
Common symptoms
What you'll notice
- Check-engine light on
- Possible reduced power or a limp/reduced-power mode
- On diesels: incomplete or skipped DPF regeneration
- May fail an emissions test
Common causes
Most likely first
- Faulty exhaust (back-)pressure sensor BLikely
- Open or short in the sensor wiring harnessCommon
- Poor, loose, or corroded electrical connectionCommon
- Clogged or damaged sensor pressure hose/port (soot)Less often
- Faulty ECM/PCM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to see the reported pressure and the conditions when it set.
- Inspect the 'B' exhaust pressure sensor, its connector, and any pressure hose for soot clogging, cracks, or damage.
- Check the sensor wiring for opens, shorts, and corrosion.
- Clean or clear a restricted port/hose; repair wiring faults.
- If the circuit and plumbing check good, replace the exhaust pressure sensor. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P047A?+
Short trips are usually fine, but the vehicle may run in reduced power and — on diesels — skip DPF regeneration, so don't put off the repair.
Can I just clear P047A?+
You can, but it returns until the sensor, its hose/port, or its wiring is repaired.
Related codes
Often seen with P047A
Read & clear P047A 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