578-9953 | Genuine Cat® EGR Valve For Electric Motor 24V

1. Reduce nitrogen oxide (NOx) emissions

By recirculating a small amount of exhaust gas back into the cylinders, the combustion temperature lowers, which reduces NOx formation.

2. Improve combustion efficiency

Diluting the air-fuel mixture under certain conditions can help the engine run smoother and reduce knocking.

3. Improve fuel economy (in some engines)

Especially on highway cruising or light-load situations.

1. Rough Idle or Engine Stalling

A stuck-open EGR valve lets too much exhaust into the intake at idle, causing:

• Rough, shaky idle

• Engine stalling when stopping

2. Poor Acceleration

A stuck-closed EGR valve can raise combustion temperatures, causing:

• Hesitation or sluggish acceleration

• Loss of power, especially under load

3. Check Engine Light (CEL)

The ECU will often trigger fault codes such as:

• P0400–P0409 (EGR system faults)

• P0401 (insufficient flow)

• P0402 (excessive flow)

4. Increased Fuel Consumption

Incorrect EGR flow can make the air-fuel mixture inefficient, leading to worse MPG.

5. Engine Knocking or Ping

If the valve is stuck closed, combustion temps rise and cause:

• Spark knock / detonation

• Potential long-term engine damage

6. Surging or Jerking While Driving

Intermittent opening and closing of a failing EGR valve can cause:

• Surging at steady speeds

• Jerky throttle response

7. Excessive Exhaust Smoke (More Common on Diesels)

• Black smoke = stuck closed

• White/grey smoke = stuck open or EGR cooler issues

8. Failed Emissions Test

High NOx emissions usually indicate an EGR system problem.