P047F
Exhaust Pressure Control Valve A Stuck Open
Exhaust / emissions
Generic OBD-II
Medium
What it means
P047F means the ECM has determined the "A" exhaust pressure control valve is stuck in the open position. Because that valve creates backpressure to help the engine warm up and brake, a valve stuck open usually shows as slow warm-up and reduced exhaust braking rather than a running problem. Carbon buildup and a seized shaft are the usual culprits.
Medium
Can I keep driving? Drivable — the main effects are slow warm-up and weaker exhaust braking; there's no immediate risk of being stranded.
Common symptoms
What you'll notice
- Check-engine light on
- Slow engine warm-up in cold weather
- Reduced exhaust-brake performance (on diesels)
- White smoke or longer cold-start warm-up
- Poor fuel economy in some cases
Common causes
Most likely first
- Carbon buildup holding the valve openLikely
- Seized or worn valve or actuator linkageCommon
- Faulty valve actuator or control solenoidCommon
- Damaged or shorted wiring or connector at the valveLess often
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the exhaust pressure control valve for carbon buildup or a seized shaft holding it open.
- Clean the valve and linkage before replacing parts.
- Check the actuator wiring and connector for damage or a poor connection.
- Replace the valve or actuator if it will not close and hold. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P047F?+
Yes, in most cases. A valve stuck open mainly affects warm-up and exhaust braking, not whether the car starts or runs. Repair it to restore normal cold-weather and DPF operation.
Can I just clear P047F?+
The valve is stuck open mechanically, so clearing the code won't fix it — it returns once the ECM tests the valve again.
Related codes
Often seen with P047F
Read & clear P047F 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