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ENRUDEPLES

P0403 — Exhaust Gas Recirculation Control Circuit

moderate

What it means

This is an electrical fault: the control module detected an open circuit, a short or an out-of-range current in the wiring that drives the EGR valve solenoid or stepper motor. It is set by the driver stage monitoring inside the ECM, independently of how much gas actually flows. The valve usually stays in its default position, so the engine may knock under load or idle roughly depending on where it was left.

Likely causes (most common first)

  1. Open, chafed or corroded wiring between the ECM and the EGR valve
  2. Corroded or loose connector at the EGR valve or its solenoid
  3. Failed EGR solenoid or stepper motor winding (open or shorted coil)
  4. Blown fuse or lost supply voltage on the EGR feed circuit
  5. Poor engine ground causing an out-of-range control current
  6. Failed driver stage inside the engine control module

Can you drive with it?

Driving is allowed, but the EGR is effectively disabled and emissions rise, so book a repair.

This is the generic meaning. What about your car?

The same code has different typical culprits on different engines. Tell the AI your make, model and year — it will rank the causes for your exact car and give you a check order.

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