Last week at a drive over 65 mph I got a check engine soon light, but when I restarted car after doing my errand the light didn't reappear and did not come back. No issue with drivability during a few other trips this week, but those drives top speed was only between 55 and 60. Today I went to a meeting that had me use the garden state parkway where I hit spends in the low 70's and no light, but on the way back, also at speeds up to low 70's light came back.

Put scanner on it and pulled a code 32 EGR Diagnostic SW Signaling Incorrect EGR Valve Operation.

Motor ran fine throughout. What should I be looking at?

 

What year car?

I had the same 10+ years ago. It was the EGR relay. It's on the left side of the engine, a small little relay.
That all I can offer at the moment. My car is a 94

 

Sorry about that it is a 91. And as additional information also had a code for MAP voltage being too high so I did change it out with replacement I had bought after having a similar code for MAP couple weeks ago. Engine run s smooth and starts right up.

 

EGR only activates when the engine is warm and you're steadily cruising at part throttle, so it mainly runs when youre on the highway and cruising. The code shows up when the ECM tries to activate it and isn't getting the right signal back. Once the ECM isn't using it the SES will usually turn off but the code is in memory.

Its probably the solenoid/switch on the passenger side at the rear of the intake manifold. The FSM will have a procedure to go through to troubleshoot it to be sure.

Its not a big problem at all but you would have to have it working for NJ emissions testing and inspection. The engine doesn't really care if the EGR is working or not.

 

The research I've done today did confirm what you said and I will be doing tests that are recommended in the FSM tomorrow. In New Jersey any cars older then 95 no longer have to be inspected, but even though the problem doesn't affect drivability the check engine soon light will drive me nuts.

 

On my '88 I had the same problem.

It would only activate the code and light on the highway cruise. Mine turned out to be the EGR valve itself.

My caution is that when I got a new one, the part was bad. It would not hold a vacuum and operate the valve. I got a replacement and it was bad also. I took it back to the store again and the third one was the wrong part in the box with the right part number. I gave up on the local store and bought an AC Delco from Rock Auto. That one worked fine. I installed it and it cured the problem that I was having.

Good luck.

 

I had an EGR fail on my 1988 C4 and I am pretty sure it all started with the EGR Vacuum switch that activates the EGR by applying vacuum at the right times. If the vacuum disappears the switch can do nothing to the EGR and it gets buggered up with carbon.

The switch needs a good source of vacuum and something as little as a vacuum leak will trigger the code/problem. Be sure that your vacuum system is intact and supplying vacuum to the EGR. The EGR it self can be tested using a vacuum pump attached to the EGR body vacuum line, when vacuum is applied it should move the diaphragm and you will hear a difference in your idle as you do it. If the EGR does not move then you need to remove it and clean out the lines. If the EGR does move then you are likely to find the problem at the EGR Vacuum switch.

On my C4 the CEL did not come on and I received no codes from the car either. After the EGR went bad the combustion chamber temperatures go up too high. The tube that we have over the passengers side valve cover has a insulated cover on it and my new cover started to melt from the extra heat from having a defective EGR. I learned about the problem when I had my emissions tested and failed due to higher NOX levels than Virginia allows. The elevated NOX is an indicator that the EGR has indeed failed.

Start simple, check the vacuum lines and even measure what the EGR vacuum solenoid has at it's connection.
Next test the EGR diaphragm for movement using a vacuum pump or some source of vacuum. Watch for the movement of the EGR and listen for the change in idle.
No movement, start ordering the parts you will need. Some EGR's are getting harder to find and more costly to boot.

Don't try to remove the EGR system from the Corvette. You have to change the "code" to do it properly. The EGR helps the car while it is running in a positive way. Without a good EGR your car will have higher combustion chamber temperatures and it will use more gasoline and will be likely to detonate.

When you get a new EGR you should check to see if it holds a vacuum before installing it. A vacuum pump will tell you very quickly.

From what I have read the EGR temperature sensor can fail and that will trigger a CEL. Mine was completely "D-E- A- D" and it indicated nothing on the dashboard that I had a problem. Is your 1988 an automatic or manual?

Best regards,
Chris

 

i see no ay that the EGR can do much of anything other than lower NOX and does not make mileage better.