Check Engine Light on

My "Check Engine" light came on & stayed on yesterday (at least for our 140-mile trip home).

What's the usual cause of this on the G20, and is the fix easy?

Regards, Don Swier

Self Diagnosis Scans (http://www.imagestation.com/album/?id=4291851895)

Lucky for you I have scanned the pages in my FSM detailing Self-Diagnosis Mode for the ECU. Follow the instructions and the car should give you a code telling you what the problem is. However, there are some parts that can't self-diagnose themselves, in this case, get thee to a shop.

IF it's your O2 sensor (which mine was about a month ago) do not take the car to the dealer for it. They'll charge you $300 or so dollars, and you can do it yourself for $70, 5 minutes, and a wrench.

Thank you much!!

Once I've replaced the Oxy Sensor, and the problem is resolved, won't the Check Engine Light still be on until it is turned off?

I knew where the secret switch was on my old Bosch-injected VW GTI, but how do I extinguish the dash light on a P10 once I've replaced the Oxy Sensor?

If you have the answer, I'd be eternally grateful.

-Regards, Don Swier.

Eternally grateful eh? Hmmmm...

I actually don't know where the switch is on mine. I took it to the dealer and told 'em to reset the ECU. They were nice, didn't charge me the $78 it's supposed to cost and just told me to tip their guy.

I will check my FSM later tonight and see what I can tell you.

It was your o2 sensor, though?

hummm..., we have a similar G. Did you reached 150k yet? Did you drive more than 6 hours straight after the light went on? The reason I'm asking these questions is because it happend to me.This is just my theory why my light went on. I thought it was the EGR valve, BPT, oxygen sensor, and other stuff. But I searched around for answer and finally followed how to check and reset the ECU unit. You can check the code of your ECU if it's telling you something is wrong. Mine came out negative and after finding out nothing was wrong with the engine system..., I reset the ECU, then the light vanished and never come back. It's been probably more than 4 months now.

Good Luck!

oxigent sencer. check it. that was my cause same trip home (130miles).

Once you've replaced the oxygen sensor, the ecu should automatically turn the cel off (if that was the problem). The ecu periodically runs checks on all of the emissions equipment, and if the voltage for the 02 sensor is correct, it will no longer have the MIL (malfunction indicator light, the proper name for a check engine light) HTH

Originally posted by Cliffgump
Once you've replaced the oxygen sensor, the ecu should automatically turn the cel off (if that was the problem). The ecu periodically runs checks on all of the emissions equipment, and if the voltage for the 02 sensor is correct, it will no longer have the MIL (malfunction indicator light, the proper name for a check engine light) HTH

Nope. I replaced mine and drove it 120 miles a week later to the Infiniti dealership so they would reset the ECU. The guy who reset it looked at the machine and said 'You've started this car 37 times since the "Check Engine" light turned on?!?!' Yep, I had. You have to actually reset the ECU. It doesn't turn the light off itself.

Originally posted by boingo82: Nope. I replaced mine and drove it 120 miles a week later to the Infiniti dealership so they would reset the ECU. The guy who reset it looked at the machine and said 'You've started this car 37 times since the "Check Engine" light turned on?!?!' Yep, I had. You have to actually reset the ECU. It doesn't turn the light off itself.

That's really weird, does the SR20 use an OBDI system? My old 95 contour used this system before manufacturers changed to OBDII. My CEL's would always reset themselves, sometimes it took a long ass time ( three weeks on one of them ) to reset, but eventually it did. And I had a lot of CEL's with that POS. Anyway isn't it possible to pull a couple of fuses to reset the ECU? Again something I could do on my contour.

Originally posted by Cliffgump


That's really weird, does the SR20 use an OBDI system? My old 95 contour used this system before manufacturers changed to OBDII. My CEL's would always reset themselves, sometimes it took a long ass time ( three weeks on one of them ) to reset, but eventually it did. And I had a lot of CEL's with that POS. Anyway isn't it possible to pull a couple of fuses to reset the ECU? Again something I could do on my contour.

Nope, the G20 uses OBDII. And you can leave the battery disconnected overnight, according to legend.

Disconnect the negative battery turnminal for an hour or two or overnight and it should go off. It did for me.

Originally posted by boingo82
Nope, the G20 uses OBDII. And you can leave the battery disconnected overnight, according to legend.

You meant your G20 right?

The '91 - '93('93.5) G20's were running OBD-I. They can be reset by the legendary battery disconnection.

The '94-'96 OBD-II's will not fully reset the ECU just by disconnecting the battery for a period of time. You have to follow the simple 10 min or less procedure to reset the ECU correctly at the ECU screw.

I've had my engine light come on before (have a '94 G20) without there actually being something wrong (I took it in and had it diagnosed), so I haven't worried about this time either because everything seems to be running as usual. But I'd feel better if I knew for sure.
So...read ya'lls stuff and want to run the self diagnostic, but just need a little more help since I don't have an FSM and would be a female that is not necessarily mechanically inclined. At the sake of sounding helpless, could someone run me through what I need to do so I don't have to go pay some mechanic a bundle...:rolleyes: thanks!

Second post at the top. :) You stuck in Utah, too?

hey guys light went on got the codes but really confused on what it is, some say the egr and some say the O2, does anyone know the correct codes for a 93.5 G20. By the way, to reset the CEL, locate the ecu in the lower dashboard area, near firewall. remove the cover on passenger side, Center, and u should see the ecu, it even tells u how to run diagnostics and reset the ecu, which is, turn the screw clockwise fully and then counter clockwise fully, thats it.