Exhaust Gas Recirculation Flow Insufficient Detected
When exhaust recirculation was requested, the computer detected less flow than expected using that engine's monitoring method. Carbon restriction is one possibility, but a valve that does not open, a control problem or incorrect feedback can produce the same finding. This does not diagnose a blocked catalytic converter. The EGR flow path and control data need assessment together.
Can I keep driving?
If the engine stalls, the light flashes, shaking is severe, or power loss makes traffic unsafe, pull over safely and arrange towing. With a steady light and normal operation, ask a shop for advice based on symptoms before further driving.
What does this code mean for your car?
The same code can need different checks depending on the model and engine. Enter your vehicle details to find relevant sources and checks.
Symptoms
- Check engine light
- Unstable idle or stalling in some cases
- Hesitation or reduced response
Possible causes
- 1EGR passage restricted by deposits
- 2EGR valve failing to open
- 3Actuation or vacuum supply fault where fitted
- 4Faulty feedback sensor or measurement hoses
These possibilities are not ranked by frequency and do not diagnose your vehicle.
Checks you can safely do yourself
Safe checks only: engine off and cold, car on level ground.
- Save the code and freeze-frame data if your scanner offers them, without clearing anything.
- With the engine off and cool, look at accessible hoses and wiring for obvious damage without removing the EGR assembly or using cleaning chemicals.
When you need a shop
Stop and arrange towing for stalling, severe shaking or unsafe power loss. Diagnosis should compare the EGR command with feedback, test wiring and actuation, and inspect the flow path as indicated for that engine.
How much does it cost?
A US repair estimate needs a diagnosis and a local shop quote.
No verified US repair quote is available for this fault. The price depends on diagnosis, vehicle, parts and local labor; request 2-3 itemized quotes.
Get 2-3 quotes
Investigate this code for my carFAQ
Can I keep driving with P0401?
If the engine stalls, the light flashes, shaking is severe, or power loss makes traffic unsafe, pull over safely and arrange towing. With a steady light and normal operation, ask a shop for advice based on symptoms before further driving.
What can cause P0401?
Possible causes include eGR passage restricted by deposits; eGR valve failing to open; actuation or vacuum supply fault where fitted; faulty feedback sensor or measurement hoses. These are diagnostic possibilities, not a confirmed diagnosis or a parts shopping list.
Does clearing the code fix the problem?
No. Clearing a code does not repair the problem or prove that no fault exists. It may erase useful evidence and reset readiness monitors. Save codes and freeze-frame data first; confirming a repair requires the vehicle-specific checks.
What if this code appears during a used-car inspection?
Arrange an independent professional pre-purchase inspection before committing. Request a complete scan, readiness status and diagnosis of the relevant system. Get written findings and a repair estimate; an unlit warning lamp does not replace inspection.
How much does a P0401 repair cost?
No verified US repair quote is available for this fault. The price depends on diagnosis, vehicle, parts and local labor; request 2-3 itemized quotes.