What it means
The exhaust flow control valve C reports a control circuit/open condition. Exhaust routing for back-pressure or noise control on this branch cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Exhaust flow control valve C uses an actuator circuit to change exhaust routing on its branch. The engine control module detects an open control circuit, so it cannot reliably command valve C and exhaust routing may be affected.
Common causes
Most likely first.
- Open in actuator control wire
- Open actuator coil
- Pin pushed back out of connector body
Symptoms
- Check-engine light
- Change in exhaust sound
- Reduced engine performance
How to diagnose it
- Read freeze-frame data and valve C command and position data to see when the open-circuit condition was detected.
- With the exhaust cool and the system powered down as specified by the manufacturer, inspect valve C’s wiring and connector for damage, loose terminals, or a pushed-back pin.
- Check the actuator control wire for continuity and inspect its connector terminals for a break or poor contact.
- Test valve C’s actuator coil for an open circuit using the manufacturer’s procedure and specifications.
- If the circuit and coil are intact, check the control-module output and valve position feedback using the manufacturer’s diagnostic procedure.
Common fixes
- Reconnect a loose valve C connector or secure a pushed-back terminal.
- Repair an open or damaged valve C control wire.
- Replace valve C’s actuator if its coil is open.
- Repair a confirmed control-module circuit fault if wiring and actuator tests pass.
Can I keep driving?
If the vehicle remains stable, drive gently and avoid hard acceleration; stop if engine performance drops sharply or the exhaust becomes unusually loud. The valve may not control exhaust routing, so have the circuit checked soon.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.