P2425 EGR cooler: open circuit

By: Diagno editorial team · Updated: 2026-10-15

P2425 means: EGR cooler: open circuit. The EGR valve sends part of the exhaust back into the intake to cut emissions. OK to drive, but have it checked soon. The repair usually costs about €60–300 in Estonia. The most common cause: connector loose, damp or corroded.

What it means

The EGR valve sends part of the exhaust back into the intake to cut emissions. The computer found too much or too little flow, or a fault in the valve's electrics. The computer sees no current in the circuit, so something is open: a wire, a connector or the part's winding.

What you may notice

• Engine light on
• Less power
• Rough idle
• Black smoke on diesels

What could be wrong

1. 1Connector loose, damp or corroded
2. 2Wire broken or chafed
3. 3Faulty EGR valve
4. 4Engine computer fault (rare)

Repair difficulty: Moderate

What you can check yourself

First look at the connector and wiring: anything loose, melted or green with corrosion? Lots of short trips clog the EGR quickly. Sometimes a longer motorway drive helps. You can check the simple things yourself, but the repair is best done in a workshop.

How we fix it

1. We read the fault data on the diagnostic tool and check whether the fault is constant
2. We measure the circuit's supply, ground and signal
3. We repair the wire or replace the connector
4. If the wiring is fine, we replace the EGR valve

Standard SAE description: Exhaust Gas Recirculation Cooling Valve Control Circuit/Open