What it means
The exhaust flow control valve A reports a position circuit low 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 routes exhaust to manage back-pressure or noise, and a position sensor reports its movement to the module. This code is set when valve A’s position-sensor signal is lower than the module expects, which can result from a grounded signal wire, a shorted sensor, or poor connector contact.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Reduced engine power
- Poor acceleration
How to diagnose it
- Check freeze-frame data and valve A’s live position signal to confirm the low reading occurs under the recorded operating conditions.
- Inspect valve A’s sensor connector and harness for corrosion, pin damage, or insulation rubbed through to ground.
- Check the sensor ground, reference supply, and signal wire for shorts or poor connections using the wiring diagram.
- Measure the signal circuit and sensor supply against the manufacturer’s specification to locate whether the low reading is in the harness or sensor.
- If the wiring and connector are sound, test valve A’s sensor and replace it if its output remains low.
Common fixes
- Clean and secure corroded or loose valve A sensor terminals.
- Repair a signal wire shorted to ground.
- Repair damaged sensor wiring or connector pins.
- Replace valve A’s position sensor if it is internally shorted.
Can I keep driving?
A short, gentle drive may be possible if the engine runs normally, but avoid hard acceleration and be prepared for reduced power. Stop driving if power loss makes the vehicle unsafe; the valve position may not be controlled reliably, affecting drivability and emissions.
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.