jonny4523

What is it that triggers that check engine light?

Jvette73

are we talkin about the check engine light on yur 77 vette? Usually the computor makes the light come on after its recieved a trouble code from one of the sensors. The trouble codes are stored in the computor. on many GM models its easy to read the trouble codes to see whats causing the light to come on. I put a couple of pics below to show you what the diagnostic connector looks like. Its usually visible along the underside of the dash. Check to see if yur car has one of these. If so I can tell you how to read it with a simple paperclip. Post back if yur car has one of these.

this is what the cover looks like


this is what the connector looks like when the cover is removed

Gator81

On a '77, I don't know. The first year for a computerized control system on a Corvette was '81. From that year on, a "check engine" light on meant an emissions control system malfunction. That is, some parameter was outside its normal operating range; for example, if the oxygen sensor is reading an overly rich exhaust, and the computer cannot make adjustments to bring that reading into the normal range, then the computer turns on the light.

stickboy

:iagree: , but first year for the computer was the 1980 california model. !981 was the first year for all vetts to have a computer

Jvette73

Thats what I thought. I didnt think a 77 had a check engine light so thats why I asked. But if it does, and it looks like the one in the pic I posted above, I can explain how to easiely read the computors stored trouble codes.

Metal Wulf

I've never seen a check engine light on my car :skep:

timbo79

:iagree:
No Check engine light on my 79, no computer controls, yet. I will as soon as I swap into a TPI unit, but in 1979, NO Check Engine Light. Are you asking about your '77? or another car.. Emissions is usually the culprit, i.e MAF Sensor, O2 sensor, EGR, PCV, etc....

Yeller81

If the Idle is to low that will trigger the Check Engine Light but this is on my 81...

jonny4523

Sorry, I havent been home in a few days.

I was asking for my truck. its a 95 dakota. Everything seems to be running fine but that dang light comes on and its annoys the crap out of me.

Jvette73

Sometimes you can get a false trigger on a trouble code. Try this: Dis-connect the battery for 10 seconds then re-connect. That should erase the trouble codes. At least GM is that way. Just make sure the key is not in the ignition when you do it. if you disconnect the battery while the key is in the on position it will erase all data in computor. Thats not a good thing.

jonny4523

So what is the light that is labeld "GEN"? On my vette, it is the top right light on the middle console.