code 32 SES light

[Z Ya Later]

So, the SES light decides to pop up Fri. night out of the blue. I'm driving on I580 out to Pleasonton and I get to the hill to head into the city...and my SES light pops up. I get to where I need to go, turn the car off then back on and its fine. I'm heading back and, sure enough, the SES light pops back on on the incline. I go up the hill I take to school though and its fine, and this hill is steeper. So, I take it to my mechanic and it returns 32...EGR problem. Anybody have any advice? Thanks.

[TruckMuddr]

Not sure if this helps any.


DTC 32 WILL SET WHEN
Vehicle speed between 16 - 50 MPH for Automatic Transmission (A/T) or 25 - 65 MPH for Manual Transmission (M/T) , vehicle coasting A/T, throttle angle 0% A/T or throttle angle between 8% and 20% M/T, transmission in 3rd gear or higher, Manifold Absolute Pressure (MAP) within range as shown in table (depends on altitude), no change in A/C status, DTCs 21, 22, 24, 33, 34 not set, Barometric Pressure (BARO) greater than 80 kPa (depends on altitude), all conditions met for 2.5 seconds, and the PCM does not detect at least 1.0 kPa change in MAP when it commands EGR "ON" A/T or when the PCM commands the EGR "OFF" M/T within the 1.5 second period of the test.




I'll keep looking.

[Z Ya Later]

So then it has nothing to do with the amount of backpressure that exists? Thanks for the quick reply man.

[TruckMuddr]

Well, it does. I'd copy some more off of alldata but there site is down right now.

[Z Ya Later]

Ok, after reading your description further, this presents a problem. I was cruising at 75, which is above above the speed range that you said. Any ideas? Thanks for you help man, I really appreciate it.

[Injuneer]

The code is set because the system is not detecting EGR flow. If your EGR system is still connected, the valve isn't operating. It needs to be cleaned or replaced.

Backpressure is a key issue, because the flow volume of EGR is dependant on the manifold vacuum pulling it in, and the exhaust pressure pushing it in.

The code is very unusual in OBD-I (93-95) and generally means a faulty valve.

[Jeff_in_Atl]

I had that on mine. I took it to the dealer where they hooked up some machine and flushed the carbon out of the pipe and they cleaned the valve. It hasn't come on since and that has been about a year ago. I think it cost about $175. He showed me the valve. It had carbon all over it. The dealership said they do this service all the time on GMs.

[Z Ya Later]

Thanks Fred and Jeff. So, would it better then to take it a) to a dealer (*shudder* lol), b) my mechanic or c) take it off myself and have someone clean it? I know it sits on the back of the intake...question is, just how hard is it to get it off? Thanks for the info guys.

[Fastbird93]

Originally posted by Injuneer
The code is set because the system is not detecting EGR flow. If your EGR system is still connected, the valve isn't operating. It needs to be cleaned or replaced.

Backpressure is a key issue, because the flow volume of EGR is dependant on the manifold vacuum pulling it in, and the exhaust pressure pushing it in.

The code is very unusual in OBD-I (93-95) and generally means a faulty valve.

It's the problem that I had with my valve. It was faulty when I threw that code.

For what it's worth, take it off yourself and check it. If you need a new one call Jason Cromer, they're only like $40 for a brand new one.

[Injuneer]

Its pretty well hidden in the back of the intake manifold. It has a single vacuum line that is easy to disconnect. Then the manifold has two studs in it, and two nuts holding the valve to the manifold. I think they are 13mm. You can see one of them from the driver's side. The other can be removed by "touch", or you could try a small mirror.

Now, I'm basing all this on the 94-97 intake, and the 93 may be slightly different.

I would do it myself if I were you. I have a brand new valve + gasket for a 1994. Not sure if it is the same part # for the 1993, but if it is, $25 + shipping and its yours.

[Fastbird93]

To clarify, the 93's are next to impossible to remove without moving anything. The EGR location and bolts are the same as the 94+ models, but the problem lies with the fuel rails. The crossover is in the rear on 93's, and on the crossover tubing, there is a large accumulator which almost completely blocks access to the passenger side EGR bolt. You will need to either unbolt and lift up the fuel rails, or just completely remove them, which is the less annoying route I found. The driver side bolt is not a problem though. Just make sure you're using a short wrench and you should be good.

Seeing what you have to go through, now think about what a dealership would charge to do this!!!! It's not that time consuming, but I'm sure the dealer has a 2 hour job on it or somewhere thereabouts.

[TruckMuddr]

Here is something else I found:


Intake Passage: Shut "OFF" engine and remove the EGR valve from the manifold. Plug the exhaust side hole with a suitable stopper. With the intake side hole open, attempt to start the engine. If the engine runs at a very high idle (up to 3000 RPM is possible) or starts and stalls, the EGR passages are not restricted. If the engine starts and idles normally, the EGR intake side passage in the intake manifold is restricted.
Exhaust Passage: With EGR valve still removed, plug the intake side hole with a suitable stopper. With the exhaust side hole open, check for the presence of exhaust gas. If no exhaust gas is present, the EGR: exhaust side passage in the intake manifold is restricted.

Also, A DTC 32 can be caused by a leaking exhaust system. An exhaust leak will alter backpressure. Thoroughly check exhaust system for leaks.

[Z Ya Later]

Funny you should mention the exhaust leaks. I had a few on the LoudMouth system that I just got patched up, but appearantly the cat has a very minor one and the manifolds are leaking slightly at the back (cylinders 7 + 8). Think that might be the culprit, because she still runs fine with the exception of the first time I ran it after having it diagnosed. Thanks guys for all your help so far and I'll let you know if I need a new valve.