I just replaced the alentator on my 97, and had to disassemble the air intake to make the swap. A couple of days later my check engine light came on. I read in the manual about the fail safe cooling. I checked the coolant level and it was just shy of the mark. I topped it off and reset the computer. No more light. I just swapped out the tensioner and it's back on.

One time the light came on I got a new O2 sensor.

The second time it came on I had the #2 plug and wire replaced and all the injectors cleaned.

I called the dealer and they said there were about 30 different codes for a check engine light. So, does anyone in cyberspace know why, or what caused the light to come on?

Silent Bob

 

Normally it is just emissions related stuff. But if you think of every sensor on the vehicle:

O2
MAP or MAF
Coolant Temp Sensor
TPS
Knock sensor
IAT
Vehicle speed sensor
Engine speed Sensor
Tranny Temp Sensor
EGR
EVAP

And there are lots others, but if one of those decides it is having a bad day it will turn on the light. I don't know what the tensioner would cause though, either it was a coincedence or you knocked a hose loose. Also most vehicles use 2 trip logic. If the computer sees a code it won't turn the light on right away, it will save it for later and if it sees the code again, then it will turn the light on. Unless it's an important code like a misfire code. That second one you had sounds like you had misfire codes for cylinder #2. There are probably 30 codes that would turn the light on right away. There are actualy a few hundred codes that the computer can give you.

So check for loose hoses and if all else fails have the dealer pull the code.

-Jon

 

I've got a code(?) that only lights the check engine light if I run WOT. I can drive all day normally and no code. The very first WOT run and on with the check engine light. I guess I am going to have to break down and get it read...

 

Just had mine read at Autozone, so far that's the only store I know of that will do it for you. Mine came up as a "system lean bank one." So, I bought an 02 sensor and will replace it tomorrow morning. The code was P0171. worth checking out.,,,,,98

 

how much does the zone of autoness charge you to read codes?

 

Exactly $0 dollars and 0 cents I believe they do it free, for the possibility of the parts sale. Imagine the look on their face if you didn't buy them there, lol. That would be cruel, hehehe,,,,98

 

98-

Thanks for the input, it's just too bad I'm reading it after I dropped off the truck at the dealer. Story of my life. But good info for the next time!

Silent Bob

 

Mine's about to go to the dealer now, an 02 sensor didn't solve it,,,,,sigh.,,,,98

 

I just got back from the dealer and after $75 ($65 just for the computer hook-up) it turned out to be a loose wire with a broken connector. And the broken pieces are my fault, I think I did it when I changed the altenator. Oops!

 

Hmmm... cleaning the MAF seems to have stopped it finally. Come to think of it, every time the CE light has come on has been the fault of the MAF. Sheesh, you'd think they put some kind of filter in front of it??? Anyway, the light has been off all day, lets hope it stays that way.,,,,,98