P2D18
Exhaust Flow Control Valve C Position Circuit Range/Performance
The exhaust flow control valve C reports a position circuit range/performance condition. Exhaust routing for back-pressure or noise control on this branch cannot be commanded reliably.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Sensor offset driftedCommon
- Linkage between sensor and valve loosePossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Exhaust Flow Control Valve C
- Wiring Harness
- ECM
P2D18 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.