pahoo31

Will older vehicles with this connection trigger the service engine soon light for all supprted codes if there is a problem, or only certain ones. tia

nj85z28

You can pull any code from an OBD1 system if thats what you're asking. Its not as advanced as OBDII however

pahoo31

But-will the "service engine soon" light get activated by any code supported, i have been told that not all problems will trigger the light to come on, that is if you think you may have a problem you need to hook up a scanner and check to see if any service error codes are present. tia pahoo31

EinST

The SES will light for a defined set of codes applicable to the vehicle built with a particular combination of engine and transmission. It will not light for any additional codes supported by the vehicle, e.g., for security or ABS.

pahoo31

Thanks for your reply. Do you know if it is at all possible to alter the chip setting in the vehicle computer through the obd1 port, like maybe with laptop computer or such. I ask this because since having new tires installed i now have a slight vibration felt in steering wheel and on front tires themselves, but only can be felt when vehicle is in gear and idling, moving it goes away. They did a complimentary multipoint inspection when tires were installed and one of the entrys is #2 - 99p, which i believe is the number of codes for obd1, and am thinking that possibly they may have altered somthing in the computer through this port. This vehicle also has a street hypertech chip installed which they did not know, as i went to get tires, not have diagnostics done, and don't know if possibly they could have altered its settings. Also the shifting of the auto tranny seems to be at different points through its range, as well as a change in torque conveter lock. Maybe its something unrelated to the tire install, but it sure would be a BIG coincidence. tia.

EinST

You're kidding, right? I doubt a tire place would bother hanging a scan tool on the OBD port. As for "#2 - 99p," it sounds like items "#2 - #99" of a 99-point inspection were checked. I'd guess item "#1" would be the tires. Why don't you ask them?

pahoo31

Well, i was serious with my question. My expierience with working on vehicles is long before the coming of computers and obd ports-what you can and can't do, and it was more than just a tire shop, it was a car dealership which i'm sure would have the technological equipment to change or reset the computer if it is possible. I thought about asking them but i doubt they would admit anything that might infer that they caused my issues. I probably will never know what the cause is unless it is something that gets worse with time.

EinST

The ECM in the old days had PROM chips that cannot be reprogrammed. I'd say let it go. You can still call them and ask what the "#2 - 99p" notation is about.