A2C53254318 | Genuine Cummins® EGR Exhaust Recirculation Valve for 6.7L 07-2012

1. Reduce NOx emissions (primary purpose)

When an engine burns fuel at high temperatures, it produces nitrogen oxides (NOx)—a major pollutant.
The EGR valve lowers combustion temperatures by allowing a controlled amount of exhaust gas back into the intake. Cooler combustion means far fewer NOx emissions.

2. Prevents engine knocking

Lower combustion temperatures reduce the likelihood of pre-ignition or pinging, which can damage the engine.

3. Improves fuel efficiency (in some conditions)

Under light load, recirculating exhaust gas reduces the amount of fuel needed to keep the engine running smoothly.

4. Helps meet emissions regulations

Modern engines must meet strict environmental standards, and an EGR system is one of the key ways manufacturers comply.

1. Rough idle or stalling

If the EGR valve is stuck open, too much exhaust enters the intake at idle, causing:

• Rough, shaky idle

• Engine stalling at stops

2. Poor acceleration or lack of power

If the valve is stuck closed, combustion runs hotter, which reduces performance and can cause spark knock or hesitation.

3. Check Engine Light (CEL)

Common EGR-related codes include:

• P0400 (EGR flow malfunction)

• P0401 (insufficient EGR flow)

• P0402 (excessive EGR flow)

4. Increased fuel consumption

Incorrect EGR flow can throw off the air–fuel mixture, leading to higher fuel use.

5. Engine knocking or pinging

A stuck-closed EGR valve raises combustion temperatures, increasing the risk of detonation (knocking).

6. Failed emissions test

A faulty EGR system can cause high NOx emissions, leading to a smog test failure.

7. Surging or hesitation while driving

Inconsistent opening/closing of the valve can cause the engine to surge or buck.

8. Strong fuel smell or exhaust odor

Improper combustion from EGR malfunction can create rich or incomplete burn conditions.