P047B
Exhaust Pressure Sensor B Circuit Range/Performance
Exhaust / emissions
Generic OBD-II
Medium
What it means
P047B means the second exhaust pressure sensor's signal is out of its expected range or inconsistent with other readings. This sensor supports EGR control and, on diesels, particulate filter regeneration. The usual cause is a clogged sensor tube or a failing sensor, and the engine may drop into reduced-power mode as a precaution.
Medium
Can I keep driving? Usually yes, though the engine may reduce power on diesels; drive gently and have it checked to protect the EGR/DPF system.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or limp mode (common on diesels)
- Sluggish response under load
- May fail an emissions/readiness test
Common causes
Most likely first
- Faulty exhaust (back) pressure sensor B reading out of rangeLikely
- Clogged or cracked sensor pressure tube to the exhaustCommon
- Open or short in the sensor harnessCommon
- Poor electrical connection at the sensor connectorLess often
- Failed ECM (least common)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and compare sensor B's live value against expected exhaust pressure.
- Inspect the sensor's pressure tube/hose for soot blockage, cracks, or a loose fitting.
- Check the connector and wiring for corrosion, a bent pin, or chafing.
- Replace the exhaust pressure sensor B if it reads implausibly with a clear tube and good wiring.
- Clear the code and re-test under load to confirm the repair.
FAQ
Quick answers
Is it safe to drive with P047B?+
Usually yes, but the engine may cut power to protect the exhaust system. Drive gently and have it diagnosed soon, especially on a diesel.
Can I just clear P047B?+
It clears, but returns if the sensor, its tube, or the wiring is still producing an out-of-range signal.
Related codes
Often seen with P047B
Read & clear P047B 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