P0402 means exhaust gas recirculation flow excessive. Too much exhaust gas is being recirculated — the opposite of P0401. The engine gets too much inert gas, causing rough id
Drive gently and get it diagnosed within days.
Too much exhaust gas is being recirculated — the opposite of P0401. The engine gets too much inert gas, causing rough idle and stalling.
Most common — carbon holds it open.
Misreports valve position.
Commands too much flow.
Valve can't seat.
Typically $150–$500
Cleaning typically $150–$300; valve replacement typically $250–$500. Estimates vary by vehicle. Costs are estimates and vary by vehicle, location, and shop.
Driveable but unpleasant — rough idle and stalling at stops. Fix within days.
Typically $150–$500. Cleaning typically $150–$300; valve replacement typically $250–$500. Estimates vary by vehicle.
Drive gently and get it diagnosed within days.
The most common cause is egr valve stuck open. Most common — carbon holds it open.