What it means
The position sensor for exhaust heat exchanger bypass valve A reports a performance condition. Heat recovery routing cannot be verified reliably.
At a glance
- Usually lights the check-engine light
How it works
The position sensor on exhaust heat exchanger bypass valve A reports how far the valve has moved, allowing the control module to check exhaust heat-recovery routing. This performance code sets when the sensor signal is electrically present but its reported position or response does not match the expected valve movement.
Common causes
Most likely first.
- Sensor offset drifted
- Linkage between sensor and valve worn
- Sensor element aged beyond calibration window
Symptoms
- Check-engine light
- Reduced engine power
- Lower fuel economy
How to diagnose it
- Save freeze-frame data and compare commanded with reported bypass valve A position, noting whether the discrepancy occurs at a particular operating condition.
- With the exhaust cool, inspect the linkage between valve A and its sensor for looseness, wear, binding, or damage.
- Use live data while commanding valve A through its range, if supported, to check whether the sensor reading tracks movement smoothly and consistently.
- Inspect the position sensor and its connector for mounting shifts, corrosion, or damage that could create an offset reading.
- Test the sensor response and valve travel according to the manufacturer's procedure to distinguish sensor drift from worn linkage or a sticking valve.
Common fixes
- Repair or replace worn or loose linkage between bypass valve A and its position sensor.
- Correct a shifted or loose sensor mounting if the manufacturer's procedure permits adjustment.
- Replace the position sensor if its response is outside the manufacturer's calibration range.
- Repair a sticking bypass valve if it prevents the sensor from tracking actual movement.
Can I keep driving?
The vehicle may have reduced power or fuel economy because exhaust heat recovery cannot be verified correctly. Avoid sustained heavy loads if power is limited, and stop if exhaust fumes enter the cabin.
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.