service engine soon light...

[Kgal59]

My "service engine soon" light comes on in my '94 Camaro (V6 automatic) sometimes - it only happens when I am going fast (more than 50 or 60 mph) and do not have my foot on the gas (usually when I am coasting downhill, but occasionally happens when I am going uphill on a freeway but do not have my foot on the gas). Sometimes it goes out, but usually stays on until I turn the car off - when I start the car again, the light is not on. Anyone have ideas about what might be causing this?

[MT-2500]

Originally Posted by Kgal59

My "service engine soon" light comes on in my '94 Camaro (V6 automatic) sometimes - it only happens when I am going fast (more than 50 or 60 mph) and do not have my foot on the gas (usually when I am coasting downhill, but occasionally happens when I am going uphill on a freeway but do not have my foot on the gas). Sometimes it goes out, but usually stays on until I turn the car off - when I start the car again, the light is not on. Anyone have ideas about what might be causing this?

Codes??
You need to have the codes checked and post back codes.
MT

[bag91]

Originally Posted by MT-2500

Codes??
You need to have the codes checked and post back codes.
MT

bet you its your egr valve......mine did the same thing until I had to get it smogged/ fixed....

[blindeyed]

Originally Posted by bag91

bet you its your egr valve......mine did the same thing until I had to get it smogged/ fixed....

Mine does it all the time. Had it scanned multiple times just to make sure. It's probably just that, not much to worry about, especially if it only comes on periodically. But if you're gung ho into fixing it, then good luck. I've taken mine apart, cleaned it out real good, put on new gaskets reinforced with silicone gasket maker and it still sets off the SES light. It doesn't go off as much now though.

[wrightz28]

I'm not 100% on the OBD I hybrids on this, but EGR vavle operation is usually uner light load at about 2-2500 rpm accelerating.

I'm more prone to say a O2 or possible EVAP.

Either way, get it scanned to be sure.

[Kgal59]

Does anyone know where I can get the codes checked for cheap/free? I don't know how much that normally is... Also, what is an egr valve? (Sorry, I'm a girl and don't know what every little thing under the hood is) Just curious what it is/does...

[kahjdh]

My guess would be a bad cat since it only comes up at highway speed. Some autozones check codes but mine dont so i dunno.

[MT-2500]

Originally Posted by Kgal59

Does anyone know where I can get the codes checked for cheap/free? I don't know how much that normally is... Also, what is an egr valve? (Sorry, I'm a girl and don't know what every little thing under the hood is) Just curious what it is/does...

Auto zone and some parts plces do it for free.
But some 94 -95 you may need a special scanner to get codes.
Or you may be able to just do it with a paper clip.
Have a look hear and see what your diagnostic connector looks like.
http://www.troublecodes.net/GM/

But on free code check
Use Caution when getting the free code checks please.
Some parts places do offer free code checks. And also free repair advice. But beware. Just get the code no and post it back here and someone will help you.
They offer the free code checks in the hope of increasing there parts sales.
Almost all of them will also offer mechanical advice and some know what they are doing.
But just remember most of them are parts people pulling codes for free.
Not trained professional tech/mechanics. Even if they pull a 02-sensor code or another sensor related code it does always mean to replace that sensor and your problem will be fixed.
Please just get the code no and post it back here and we will help you.

MT

[blindeyed]

Originally Posted by MT-2500

Auto zone and some parts plces do it for free.
But some 94 -95 you may need a special scanner to get codes.
Or you may be able to just do it with a paper clip.
Have a look hear and see what your diagnostic connector looks like.

No special scanner needed to read the codes from my 95. I just go up to Advance auto and theirs reads mine fine (they have a scanner that reads both OBDI, and OBDII). But most unexperienced people up there who don't know how to work the scanner will tell you that it wont read the codes. Thats when I have to teach them and tell them to go in and enter the vehicle information into the scanner (Year, make, model, engine) and then read the codes. When you hook it up normally It'll try to read it as if it's OBDII, thats why you have to enter the vehicle information into it. I'm not sure though if 94's have the OBDII connector on it like my 95 does.

[Kgal59]

Dang - wish I'd seen that last message before I went to Autozone this weekend to get it checked out. The guy there said his code reader wouldn't work just for that reason, and that I'd have to take it to a mechanic, which, apparently after reading that last post, isn't true. I'll try to take it somewhere next weekend to get the code read.

[MT-2500]

Originally Posted by Kgal59

Dang - wish I'd seen that last message before I went to Autozone this weekend to get it checked out. The guy there said his code reader wouldn't work just for that reason, and that I'd have to take it to a mechanic, which, apparently after reading that last post, isn't true. I'll try to take it somewhere next weekend to get the code read.

It may depend on the scanner AZ has and what system your car has.
Some 94 and 95 were change over years.
Some code readers and some scanners will not read codes on some 94/95 GM cars.
Check your diagnostic connector
http://www.troublecodes.net/GM/