What it means
The control module detects a high electrical condition in the exhaust heat exchanger exhaust bypass valve A control circuit.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Exhaust heat exchanger bypass valve A changes the exhaust route through or around the heat exchanger. The control module monitors the valve's electrical control circuit. This code sets when circuit voltage is higher than expected, often because the control wire is shorted to a power supply or pinched against a battery-positive feed.
Common causes
Most likely first.
- Control line shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Exhaust heat exchanger may not bypass as commanded
- Possible change in exhaust heat management
How to diagnose it
- Save freeze-frame data and check for related valve A codes to see whether the high circuit condition occurred with a particular operating state.
- With the exhaust cool, inspect valve A's harness for pinching, melted insulation, or contact with a power wire.
- Check the valve A connector and terminals for corrosion, looseness, or signs of a poor connection.
- Use the wiring diagram and manufacturer's procedure to check the control line for a short to supply and verify circuit connections.
- If the wiring and connector pass, test the valve A actuator and module control output for a source of the high signal.
Common fixes
- Repair a pinched or damaged valve A control wire that is touching a supply.
- Replace corroded or loose connector terminals.
- Separate and secure the control harness away from power wiring and hot parts.
- Replace the valve A actuator if testing identifies an internal electrical fault.
- Repair the module connection if circuit testing locates the high condition there.
Can I keep driving?
If the heat exchanger is not bypassing as commanded or exhaust heat changes, avoid heavy loads and prolonged high-speed driving until diagnosed. Continued operation may impair exhaust heat management.
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.