Exhaust Gas Recirculation Flow Insufficient
What it means
The exhaust gas recirculation system routes a small amount of exhaust back into the engine to lower combustion temperature and emissions. This code means the computer opened the EGR valve but did not see the expected change, usually because carbon has clogged the passages.
Symptoms
- Check engine light on.
- Pinging or knocking on acceleration or uphill due to hotter combustion.
- Slight increase in fuel consumption.
- Failed emissions test.
Possible causes
- EGR passages blocked with carbon.
- EGR valve stuck closed or dirty.
- Damaged vacuum hose or control solenoid for the valve.
- Faulty manifold pressure sensor used to monitor flow.
- Damaged valve connector or wiring.
How to diagnose and fix
- Inspect the valve connector, wiring and vacuum hoses.
- Remove the valve and clean off carbon.
- Clean the recirculation passages in the intake manifold.
- Test valve movement with a scan tool.
- Replace the valve if it still does not move after cleaning.
Repair cost
Cleaning the valve and passages is usually in the lowest tier, while an electronic valve replacement may reach the second.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Frequently asked questions
Is the pinging noise dangerous?
Persistent knocking means abnormal combustion that can damage pistons over time. Reduce engine load and use the recommended fuel grade until it is fixed.
Can the EGR valve be deleted?
Not recommended. It is part of the emissions system, and deleting it causes other codes, inspection failure and potentially hotter combustion.
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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