jah1542

My 2 week old Z threw a SES light on me Scan turned up a EGR valve failure. However, it doesn't always come on, and usually turns back off after a little while. (I'm assuming once it gets a little hot, the diaphragm seals back up and... problem solved.) Sounds like it's about $50 for a new one. My question is this: If I just sealed the current one off, will it have any negative side effects? I can't think of why it would, but just wanted to make sure. Thanks.

Injuneer

Which EGR trouble code are you getting - the one for a faulty vacuum solenoid circuit or the one for EGR flow? If its the one for EGR flow, its not likely blocking it off would solve the problem. The PCM operates the EGR valve (via the solenoid) and it it doesn't see the required change in the MAP pressure reading, it sets the code. Being an intermittent SES light, I'd expect that's what your problem is. To eliminate the valve and insure 100% you wouldn't get a light or a trouble code, you'd have to have the diagnostic removed (via programming) from the PCM, or use the "spoof" circuit that wires up a resistor to the MAP sensor to simulate the pressure change expected when the valve operates.

Check the valve, check for carbon buildup on the pintle, and in the hole in the manifold. Check the vacuum lines to make sure they are not leaking or disconnected. A new valve should be closer to $35-40 from one of the online discount GM parts sources.