What it means
The control module detects a low 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 electrical control circuit for this valve. This code sets when the circuit voltage is lower than expected, which can happen if the control line is shorted to ground or a damaged or corroded connection disrupts the signal.
Common causes
Most likely first.
- Control line shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light
- Reduced engine power
- Poor acceleration
- Increased exhaust heat
How to diagnose it
- Record freeze-frame data and check for other valve A or heat exchanger codes to establish when the low circuit condition occurred.
- With the exhaust cool, inspect valve A's wiring where it passes near hot or moving parts for chafing, melted insulation, or a wire touching ground.
- Inspect the valve A connector for corrosion, loose terminals, or damaged pins that could create excess resistance.
- Use the wiring diagram and manufacturer's procedure to test the control circuit for a short to ground and check its connections.
- If the harness and connector are sound, test the valve A actuator and module output to determine whether either is pulling the circuit low.
Common fixes
- Repair chafed valve A wiring and insulate it from the ground point.
- Clean or replace corroded or loose connector terminals.
- Repair a short to ground in the valve A control line.
- Replace the valve A actuator if testing shows an internal short.
- Repair the module connection if circuit testing locates the low condition there.
Can I keep driving?
If power is reduced or exhaust heat rises, avoid heavy loads and prolonged driving until the circuit is repaired. Poor heat management may worsen with continued use.
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.