What it means
Same as P2425 with the control line shorted to supply. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EGR cooling valve regulates coolant flow through the EGR cooler to help manage recirculated exhaust temperature. The engine control module monitors the valve’s control line and sets P2427 when its voltage is too high, often because the line is shorted to a supply; this can prevent the valve from responding correctly.
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
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
How to diagnose it
- Record freeze-frame data and check EGR and temperature live data to see when the fault occurred and whether EGR cooling appears ineffective.
- With the engine off and cool, inspect the cooling-valve harness for pinching, chafing, or contact with a powered wire or terminal.
- Inspect the valve connector for corrosion, loose terminals, or pins pushed back into the connector body.
- Test the control line for a short to voltage using the manufacturer’s procedure and specifications.
- If no harness fault is found, test the valve and module circuit, then clear the code and confirm it does not return.
Common fixes
- Repair a pinched or chafed wire contacting a supply source.
- Clean and secure corroded or loose connector terminals.
- Replace a faulty EGR cooling valve if circuit tests identify it.
- Repair a verified control-module circuit fault.
Can I keep driving?
Avoid heavy loads and sustained hard acceleration if the engine knocks, hesitates, or loses power. The fault can interfere with EGR cooling and increase emissions; stop driving if severe knocking develops.
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.