Ever since I bought my 91 Camaro RS 305 TBI automatic...the service engine soon light comes on while I'm on the highway going over 65 mph. it never goes on unless I'm going atleast 65. I replaced the o2 sensor and EGR valve....and for some time after I did each of those....it didn't come on. I'd say it comes on 40% of the time now when I'm going over 65. Once it comes on.....it doesn't turn off no matter how fast I go, unless I turn the car off. Does anyone have any ideas? because I don't really have the time or the money to take it to the shop to get the codes read. Thanks a lot

 

You can buy a Haynes manual for about 20 bucks and it will tell you how to get the codes and what they are. You basically take a little piece of wire about 3 inches long and plug it into 2 outlets located on the diagnostic plug that is on the bottom right of your dash on the drivers side. It may have a little cover on it that you have to pop off. Turn on your igniton and the check engine light will flash each code 3 times, the first code will be 12, it will flash once, pause, flash twice(indicating a twelve) and repeat three times then a long pause and the next code will start.Don't sweat the check engine light coming on, it's not too critical. After you check the codes you can reset it by disconnecting your battery for about 30 seconds.

 

Thank you so much

 

The way you describe the problem it sounds like EGR, the ECM requests EGR and the feedback switch isn't sending the signal back to the ECM or the ECM can't see the signal on the wire for it.

 

I just got my EGR valve replaced like 3 weeks ago though :-/

 

That diagnostic switch doesn't come with a new EGR valve, you either buy a new one or reuse the old. Also, it may not be hooked up or the wire it feeds may be broken.

 

grRRRRRRRRRRRR what does the damn diagnostic plug look like?

 

It is a little metal plug that screws into the front of the EGR valve and has 1 wire coming out of it.

 

Well I took it to Murray's Auto and had them hook up the electric code detector. Nothing came up......They said the engine light has to be on for it to show up....sh*t!!!!!!!!!!!

 

Why not read the codes yourself. All you need is a paperclip. Its here on the site how to do it.

 

The codes are stored so they still should be there. Unless you can read a code you are shooting in the dark. Also if you can afford to replace the egr on just someones advice you can pay to pull the codes if you can't do it yourself. It may be cheaper then just replacing parts.

 

They are wrong, the codes are stored for 50 starts, if they don't reoccur in that time they are erased, unless you unhook the battery/ pull the ecm fuse, then they dump.

 

For some reason my codes never show up. Even right after they happen, i put the paper clip in and all i get is code 12, nothing else.

 

Might try another ECM, see if someone can loan you one.

 

The ecm is new from NAPA. I thought it was the cause of another problem so i replaced it a couple months ago.

 

See if you can get a KNOWN good ECM and try it, its not unheard of to get bad remaned ECM's.

 

step one. remove the dash pad
step two remove the gauges
step three remove light from "service Engine Soon"

Step 4 do steps 1-3 in following oreder... 3, 2, 1

heheheh :lala:

 

I have the same problem (ses comes on only and always on the highway). I pulled the codes and it was code 32 (EGR), and I had code 54 (fuel pump) but thats probably a different story. Problem occured after new header installation. Going to check the EGR valve soon, that should do the trick...

 

I put in a paperclip in the farthest right hole on top and bottom......turned on ignition and the engine light flashed once and that was it...........wtf????? any ideas? (ive never pulled the codes before on this car...)

 

You put it in the wrong 2 holes. You want to put it in the top 2 right hand holes, Pins A & B.