I have EGR code 0302 (EGR System) . Does anybody know what might cause one?

Thanx

 

You did not specify the model year of your car. This information comes from the '99 Maxima factory service manual.

Diagnostic Trouble code 0302 points to a problem with the Exhaust Gas Recirculation system. The malfunction is detected by the Engine Control Module when no EGR flow is detected under conditions which call for EGR. Possible causes include:
- The electrical harness or connectors (valve circuit open or shorted)
- The EGR valve is stuck closed
- Weak or dead battery
- The EGR passage is clogged
- Faulty EGR temperature sensor circuit
- A leak somewhere in the exhaust system

The EGR Volume Control Valve may be tested with an ohmmeter. Disconnect the electrical connector. Looking at the connector half which is attached to the EGRVCV with the latch at the 12 o'clock position you will see two rows of three terminals. The top row is numbered 1-3, right to left. The bottom row is numbered 4-6, right to left. Measure the resistance between these terminal pairs:
2 1
2 3
5 4
5 6
... all resistance values should be 20.9-23.1 ohms at 68 degrees F.

Reconnect the EGRVCV connector halves. Turn the ignition switch ON OFF repeatedly. Verify that the EGRVCV shaft moves smoothly forward backward according to the ignition switch position.

The Exhaust Gas Temperature Sensor may be tested with an ohmmeter. The specifications are ...
- at 32 degrees F, 0.68-1.11 Megohms
- at 122 degrees F, 0.09-0.12 Megohms
- at 212 degrees F, 0.017-0.024 Megohms

 

Thanks I will try that, but also I reset the "check engine" light and havnt done anything else. The light does not come on anymore (at least for now). Does it mean that it will not come on with this code (0302) even if EGR system continues to malfunction or will it come on as soon as a malfunction is registered in EGR system?

 

When the Engine Control Module is reset it experiences complete amnesia about anything which has happened in the past. It is like a newborn ECM. It will turn on the Check Engine Light as soon as any malfunction is detected, and store the appropriate Diagnostic Trouble Codes for subsequent retrieval.