What it means
The exhaust flow control valve A reports a position circuit high condition. Exhaust routing for back-pressure or noise control 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 A changes exhaust routing for back-pressure or noise management, while its position sensor feeds movement information to the module. This code indicates valve A’s position signal is higher than expected, often because the signal is shorted to battery voltage, the sensor is open internally, or the connector has poor contact.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open position sensor
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Reduced engine power
- Poor acceleration
How to diagnose it
- Use freeze-frame and live scan data to verify that valve A’s position signal is stuck high or above the expected range.
- Inspect valve A’s sensor connector and wiring for corrosion, loose terminals, or a signal wire contacting a power feed.
- Check the signal wire for a short to battery voltage and inspect the sensor supply and ground according to the wiring diagram.
- Measure the circuit and sensor output against the manufacturer’s specification to distinguish a harness fault from an open sensor.
- If the harness and connector pass inspection, test valve A’s sensor and replace it if it cannot produce a valid signal.
Common fixes
- Restore proper contact at corroded or loose valve A sensor terminals.
- Repair the signal wire if it is shorted to battery voltage.
- Repair damaged wiring or connector pins.
- Replace valve A’s position sensor if it is open internally.
Can I keep driving?
If the vehicle has normal power and runs smoothly, keep any necessary drive short and gentle. Avoid fast traffic and hard acceleration because reduced power may occur and valve A’s exhaust routing cannot be confirmed reliably.
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.