Check Engine light - 1994 G20

Check engine light on my G20 came on after an oil change from Valvoline.

1. How can I run a diagnostic? (to flash the check engine light)

2. Where can I find the code?

3. What should I check on the car?

I checked the air filter, oil levels, oil caps, wiring.

And how to reset ECU on a 94 G20.

3rd day of owning the car and check engine light comes on after an oil change... AAARGH!


Thanks for any help.

Originally posted by g2094
Check engine light on my G20 came on after an oil change from Valvoline.

1. How can I run a diagnostic? (to flash the check engine light)

2. Where can I find the code?

3. What should I check on the car?

I checked the air filter, oil levels, oil caps, wiring.

And how to reset ECU on a 94 G20.

3rd day of owning the car and check engine light comes on after an oil change... AAARGH!


Thanks for any help.

I guess I'll answer some of my questions:

1. Run and OBDscan... found out that it is the O2 sensor that needs replacement. It was working before an oil change - would it just be a connection problem?

Anyone else doing their own OBD scanning? Is the G20 1994 an OBD I or OBD 2? I saw a post with an OBDScan tool... will have to check it out.

I can tell that my idling is rougher also. Definitely would like to replace the sensor - is it an easy replacement? Dealer wants $275 for it - that's outrageous.

I still need to reset my ECU - have to look at that in more detail since I could see a hole for a screw driver to turn.

I have gone through a search on the forum already.

I reset my ECU today and my check engine light is gone! Woohoo! Idle is also much better with no hesitation on 1st gear.

Does this mean my O2 Sensor is still okay? or since it was reset, the computer just went on default settings?

I have another PROBLEM!
i was reading the codes on my ecu and it reads
10-5
9-1
checked the se-r page
it says
1005 EGR solenoid valve circuit? 0901 Front oxygen sensor heater?
what is that?
what it looks like?
where is it?