OK - I've been experiencing some code 36 issues lately. On Sunday I cleaned the TB and made sure the connection to the MAF was secure. I cleared the codes and all was fine for some short trips on Monday. Tuesday I drove to work and all was still fine. But about 10 seconds after I started the car for the drive home the SES light came on. I pulled out my handy paperclip and sure enough it was code 36 again. :mad:

So I got out my service manual. It recommends doing what I already did. But if that doesn't work there is a handy flowchart for testing. Cool.

Step 1 is to clear the codes (no problem) start the car and let run until system goes "closed loop."

Huh?

The rest of step 1 I can handle, but how do I know when it goes "closed loop?"

Step 2 is to disconnect the MAF sensor burnoff relay (which I suspect is probably the problem anyway). Fine. I gave it a little tug but I'm not sure exactly how much of this is supposed to come out.

Any ideas? I unhooked the gray clip and tried to pull up. No go. But now I notice that there is a black clip down on the right side. Does that unhook, too? Or do I just need to pull harder after I unhook the gray one?



Once I get this off I have to test ckts 340 with a test light.

I'll go on from there.

I hate PITA problems like this.

 

Replace both relays asap. They are $10 each.

I had a code 36 last summer ago and that did the trick.

Vic

 

The Parts and Illustrations manual lists both parts as #14089936, as indicated in the picture above.

Any reason to believe that is not correct?

 

As VIC'89 recommends, change the relays. They have a tendency to get carbon build-up inside the relay, causing the problem you mentioned. They are cheap and easy to replace

 

When I replaced mine I was given 2 of the same relays.

 

An easy way to know when the ECM goes closed loop is that the fan will turn off. (after cold start up and you haven't reworked your fans)).....and it should go closed within 4 minutes after start up. In Closed Loop the ECM is using the O2 sensors to provide correct fuel delivery. Hope this helps.

 

Thanks. I knew it had something to do with the ECM not using the sensors until certain parameters are met.

 

If you got a minute could you explain this paperclip process to me? :confused:

 

I could, but here is a link that does a much better job than I could. But basically you use a paperclip to jump 2 terminals of your ALDL to retrieve any error codes stored in a computer. The paperclip method only works on '84 - '93 C4s since they used OBD-I (On Board Diagnostics - I). No '84 - '93 C4 owner should be without a paperclip in their console. You just never know when the SES (Service Engine Soon) light is going to pop up. I also keep a copy of the codes from the below link in my car. That way if something pops up I can get an idea of if I'll be able to drive it home or if I'll need a tow.

'94-'95 are also OBD-I but they use the OBD-II style ALDL. You must have a real code scanner to pull codes from this type of ALDL. '96 C4s are fully OBD-II and also require a code scanner.
http://www.c4vettes.com/ecm.htm

 

This weekend I replaced both relays and so far so good.

 

same here.replaced both relays and light stays off now.

 

yes there are two side clips on the sides holding relay also.i just took the screws loos where i could get at the relays better.