no_radio

Was driving my '96 LT4 home this evening, taking it easy, all gauges were normal. All of a sudden the Service Engine light came on. No difference in performance that I could detect. Gauges still normal the rest of the way home. When I got home I shut it off, then restarted to see if the code would return, and it immediately did (of course).
First question...how can I read the codes on a '96 with OBD II?
Second, what might be a typical cause under these conditions?
Only two things I can think of...I changed the oil Thursday night for the first time, spilled some near the filler cap, tried to get it all wiped up but there was a burnt oil smell the next day. Is it possible I spilled it onto a sensor or plug wire and cause a problem?
The other thing is that the car smelled hot when I got out this evening, although the gauges read normal. I had smelled a rotten egg smell occasionally before, could it be a catalytic converter going/gone bad?
Thanks in advance,
Jeff

DRAGRCR1005

you can get a generic obd2 scanner from summit for under 100 bucks. it will probably have a light that will flash the code and tell you were to look for a problem. if you want you can disconnect the neg. bat. cable for about 30 sec. and rehook it up. this will clear the codes and get rid of the light. alot of times they will not even come back on. most common cause of ck engine light is the o2 sensors. :chevy

CowboyNVette

Just because the light stayed on doesn't mean the car still is having the condition that caused the light to come on. It stays on for a period of time before it will reset it self. :flag

Micky Davis

Hate to hear about your troubles. I'm going through the same thing
right now. You can clear the codes by unhooking the battery a few
minutes. Drive the car as usual and see if the light returns. If it
does places like Auto Zone (the one I had pull my 300 code) will pull
your codes for nothing. You have about zero chance of guessing
your way into the solution so call around and find a place that will
pull codes and post them here for some help with what they mean
if you don't have a manual.

Good luck...........

don hall

This link will provide some info regarding your codes and a source for a code reader:
http://www.c4vettes.com/indepth_launch.htm

There are numerous sources for code readers....paper clip (free), MIDAMERICA..$40 & $80, etc......


[Modified by Oldman, 11:13 PM 1/6/2003]

96GS#007

On a '96, you can't pull the codes by jumpering the pin on the ALDL to ground, nor can you access '96 PCM codes via the CCM.

An OBDII scanner (some are cheap as mentioned above in Oldman's post, but only tell you the code number, they don't show data), scan software on a laptop (i.e. Autotap, EFILive, OBD-2, etc), or a trip to the dealer is required.

FWIW...

Mez

96GS#007 is 100% correct.

Let me try to make things a little more clear.

The OBDII cars (1996 and newer) have basically 2 computer systems. The CCM and the PCM.

CCM SYSTEM
----------------------------
When the CCM detects a malfunction, you will see "SYS" where the speedometer normally is displayed. You can pull these codes using a paper clip shorting two connectors on the under dash plug. However, these codes are set by non-engine related faults such as the radio, climate control, low battery, and other systems. The most common cause for the "SYS" is an old battery voltage dropping below 9 volts during start up.

PCM SYSTEM
-------------------
When the PCM detects a malfunction, it will display "SERVICE ENGINE SOON" in the center of the dash. These codes can only be read by using a OBDII code reader. Generally, they relate to faults detected with the emission control equipment, such as the O2 sensor, being out of normal operating parameters. Many times codes are generated as a result of a one time event and need no action. The light will go off after a few days. A number of forum members reported such events and the light goes away in less than a week.

If you pull the negative terminal on the battery, you will simply clear the PCM fault code history, thus making it impossible for a mechanic to download the history to the actual event that triggered the light.

My advice is if the car runs normal, do nothing and the light may go out in a few days. If it does not go out in a week, or the engine is not running properly, have the codes pulled. It may be a simple bad sensor or loose connection.


[Modified by Mez, 5:50 PM 1/7/2003]

no_radio

Thanks for the great replies!
I'll drive the car around and see if the code reappears.
I have a post in the Scan/Tune Forum to help select a scantool/software package, maybe next time I'll be prepared.
Jeff

milehighvette

Take a look at this site as well. It helped me with my 92. http://www.c4vettes.com/codes.htm

Good luck.

dlt4

Did you recently gas up the car? I've had the Service Engine light come on my LT4 shortly after putting gas in it. I just gave the gas cap a couple extra turns and the light went off after a few miles.

FrankLT4CE

If tightening the gas cap seems to help you also might want to buy a new gas cap from your Chevy dealer. Cost about $5.00. It made a big difference for my 96. FrankLT4CE :seeya

Mike's 86

Looks like all the bases have been covered on retrieving codes but rotten egg smell usually indicates a converter problem thus tripping an o2 sensor. :cheers: