P2C25: Exhaust Heat Exchanger Exhaust Bypass Valve A Position Sensor Circuit High

What it means

The position sensor for exhaust heat exchanger bypass valve A reports a circuit high 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 valve position so the control module can verify exhaust heat-recovery routing. This code sets when the sensor signal is higher than the expected circuit range, leaving the module unable to determine the valve position reliably.

Common causes

Most likely first.

1. Signal wire shorted to B+
2. Open position sensor
3. Connector pins corroded - high contact resistance

Symptoms

• Check-engine light
• Reduced engine power
• Lower fuel economy

How to diagnose it

1. Save freeze-frame data and check the reported position of bypass valve A for a persistently high or implausible signal.
2. With the exhaust cool, inspect the sensor connector and wiring for corrosion, damaged insulation, or a signal wire shorted to battery positive.
3. Check whether the live position reading changes when valve A is commanded to move, if the scan tool supports that test.
4. Test the sensor supply, ground, and signal circuit against the wiring diagram and manufacturer's specification, checking for a short to B+ or an open sensor.
5. If the wiring checks pass, test the position sensor itself and confirm the valve can move through its range.

Common fixes

• Clean and secure corroded or loose sensor connector pins.
• Repair a signal wire shorted to B+ or an open in the harness.
• Replace the position sensor if it is open or fails the manufacturer's electrical test.
• Repair bypass valve A if it cannot move after the sensor circuit is verified.

Can I keep driving?

Reduced power or fuel economy may occur, so avoid heavy loads if the engine feels weak. Stop if exhaust fumes enter the cabin or there is visible damage around the exhaust heat exchanger.