P0479 — Exhaust Pressure Control Valve High
Drive with caution — fix soon.
What P0479 means
This code means the exhaust pressure control valve circuit is reading a signal that's too high, often from high voltage, a short to power, or a valve stuck closed creating too much backpressure. It commonly points to a stuck valve, carbon buildup, or wiring and sensor faults. It's usually fixable by cleaning or replacing the valve and checking the circuit.
Common symptoms
- Check engine light is on
- Reduced engine power
- Increased exhaust backpressure
- Reduced fuel economy
- Possible limp mode on diesel engines
Common causes
- Exhaust pressure control valve stuck closed
- Carbon buildup restricting the valve
- Short to power in the valve wiring
- Faulty exhaust pressure sensor reading high
- Damaged connector or high circuit resistance
Typical repair cost
$150 – $650
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0479 code?
Usually yes for short distances, but don't ignore it. High backpressure can strain a diesel engine and filter. If you feel reduced power or the car goes into limp mode, have it repaired right away.
How much does it cost to fix a P0479 code?
Most repairs cost between $150 and $650. Cleaning a stuck valve or fixing wiring is cheaper, while replacing the valve or sensor raises the price depending on your vehicle.
Is a P0479 code serious?
It's a moderate concern. The engine still runs, but high exhaust pressure can hurt performance and, on diesels, strain the particulate filter, so it's best fixed soon.
Why is the signal reading too high?
A high reading often comes from a valve stuck closed, carbon buildup, a short to power, or a sensor reporting excess pressure. A mechanic will test the valve and circuit to find the cause.