Service Engine Soon light
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Service Engine Soon light
I'm getting the Service Engine Soon light after I've been on the freeway for about 5-10 miles. It stays on until I shut the car off for a while. I don't have a scanner/code puller, but I'm assuming it is probably an O2 sensor... This is a '93 coupe. I'm deciding whether to spend the $$$ to have the codes pulled, or just spend the money on a new sensor and see if that does the trick...
Any feedback would be great. Also, what's the difficulty level of finding, getting to, and replacing the O2 sensor?
Any feedback would be great. Also, what's the difficulty level of finding, getting to, and replacing the O2 sensor?
Le Mans Master
Joined: Jul 2007
Posts: 5,043
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From: Tampa Florida
Many auto parts stores will pull the codes for free.
All you really need is a paper clip to pull the codes.
Don't guess when it comes to swapping parts cause that can get expensive if you were to quess wrong.
All you really need is a paper clip to pull the codes.
Don't guess when it comes to swapping parts cause that can get expensive if you were to quess wrong.
Drifting
Joined: Jun 2010
Posts: 1,853
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From: Westerly RI
You can learn how to pull codes using the "search" function on this forum. Even if the light is off, the codes will be stored. When you get the codes, post back and someone will help interpret them.
Le Mans Master
Joined: Jul 2007
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From: Tampa Florida
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Alright, here's the scoop. I just went out and pulled the codes. I'm getting DTC 15 and 32.
STL94LT1, you sir, can pat yourself on the back. 32 is an EGR code. Per the manual, I only have to take EVERY NUT AND BOLT ON THE WHOLE CAR apart to get to it!! I think it started with "remove passenger seat, then spare tire, then the rear bumper, then the hood, engine, tranny and right hand mirror..." I joke, but it does say to lift the right side of the engine up to get to it... Fun, fun, fun...
So DTC 15 is a low coolant temp indicator. I went from the damn thing running screaming hot, to now running at 165° - 180° as long as I'm on the highway and not stuck in traffic. So apparently, it says "HEY! Remember you're in California? This thing ain't a Prius, for crap sake! Heat it up! Burn some hydrocarbons!!"
Long story short, I'll probably check out the EGR this weekend because it has been idling just slightly rough. So it might be recirculating at idle. As for the code 15? Who cares...
Thanks gang for the help!! ALWAYS appreciated!!
STL94LT1, you sir, can pat yourself on the back. 32 is an EGR code. Per the manual, I only have to take EVERY NUT AND BOLT ON THE WHOLE CAR apart to get to it!! I think it started with "remove passenger seat, then spare tire, then the rear bumper, then the hood, engine, tranny and right hand mirror..." I joke, but it does say to lift the right side of the engine up to get to it... Fun, fun, fun...
So DTC 15 is a low coolant temp indicator. I went from the damn thing running screaming hot, to now running at 165° - 180° as long as I'm on the highway and not stuck in traffic. So apparently, it says "HEY! Remember you're in California? This thing ain't a Prius, for crap sake! Heat it up! Burn some hydrocarbons!!"
Long story short, I'll probably check out the EGR this weekend because it has been idling just slightly rough. So it might be recirculating at idle. As for the code 15? Who cares...
Thanks gang for the help!! ALWAYS appreciated!!
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Not sure what manual you are using, but the egr valve is located on the upper rear of the engine, against the firewall. There are just a couple of hoses, etc. in the way for removal. I can't see where lifting the engine is necessary, or would help at all.
A couple of points: first, code 32 does not automatically mean you need a new egr valve, you need to follow the step-by-step diagnosis tree chart in the FSM, or a similar guide. Second, the two codes could be related, because if the ecm gets an incorrect temp reading, it may not be going into closed loop, or warmed-up, mode.
If you plan to diagnose this yourself, PM me and I will send you the FSM pages for these two codes. My book is for '92, but I believe they are the same.
A couple of points: first, code 32 does not automatically mean you need a new egr valve, you need to follow the step-by-step diagnosis tree chart in the FSM, or a similar guide. Second, the two codes could be related, because if the ecm gets an incorrect temp reading, it may not be going into closed loop, or warmed-up, mode.
If you plan to diagnose this yourself, PM me and I will send you the FSM pages for these two codes. My book is for '92, but I believe they are the same.
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Not sure what manual you are using, but the egr valve is located on the upper rear of the engine, against the firewall. There are just a couple of hoses, etc. in the way for removal. I can't see where lifting the engine is necessary, or would help at all.
A couple of points: first, code 32 does not automatically mean you need a new egr valve, you need to follow the step-by-step diagnosis tree chart in the FSM, or a similar guide. Second, the two codes could be related, because if the ecm gets an incorrect temp reading, it may not be going into closed loop, or warmed-up, mode.
If you plan to diagnose this yourself, PM me and I will send you the FSM pages for these two codes. My book is for '92, but I believe they are the same.
A couple of points: first, code 32 does not automatically mean you need a new egr valve, you need to follow the step-by-step diagnosis tree chart in the FSM, or a similar guide. Second, the two codes could be related, because if the ecm gets an incorrect temp reading, it may not be going into closed loop, or warmed-up, mode.
If you plan to diagnose this yourself, PM me and I will send you the FSM pages for these two codes. My book is for '92, but I believe they are the same.
I must have looked at something incorrectly about how to get to the EGR valve. I'll be REALLY happy if it's just a couple hoses that need to be moved/removed to get to it. Thanks for the help and I'll keep you posted if I need more help in troubleshooting the actual problem.
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Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
It doesn't go Closed Loop with any active Code.
The Coolant Temp Sensor is used for fuel delivery. The 15 is an open (the CTS is probably disconnected or the connector is broken) or there's no voltage drop on the reference which - sans the 15 - means the ECM is thinking the coolant temp is -38 degrees. It was designed to recognize that as an impossible situation, so it's guessing at how much fuel it needs. Fix that and it should start/idle/run a lot better.
The Coolant Temp Sensor is used for fuel delivery. The 15 is an open (the CTS is probably disconnected or the connector is broken) or there's no voltage drop on the reference which - sans the 15 - means the ECM is thinking the coolant temp is -38 degrees. It was designed to recognize that as an impossible situation, so it's guessing at how much fuel it needs. Fix that and it should start/idle/run a lot better.
Burning Brakes
Joined: May 2008
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From: Ottawa, Ontario
This allows for higher compression ratio's (good for power) while still meeting emissions requirements. The three-ways cats can only do so much, I guess.
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It doesn't go Closed Loop with any active Code.
The Coolant Temp Sensor is used for fuel delivery. The 15 is an open (the CTS is probably disconnected or the connector is broken) or there's no voltage drop on the reference which - sans the 15 - means the ECM is thinking the coolant temp is -38 degrees. It was designed to recognize that as an impossible situation, so it's guessing at how much fuel it needs. Fix that and it should start/idle/run a lot better.
The Coolant Temp Sensor is used for fuel delivery. The 15 is an open (the CTS is probably disconnected or the connector is broken) or there's no voltage drop on the reference which - sans the 15 - means the ECM is thinking the coolant temp is -38 degrees. It was designed to recognize that as an impossible situation, so it's guessing at how much fuel it needs. Fix that and it should start/idle/run a lot better.
Le Mans Master
Joined: Mar 2001
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From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
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St. Jude Donor '12
Don't know where you are located, but when I first got my 92 I would get the 32 code anytime the computer checked the EGR operation. If you are near Road Atl, come on out next weekend and I can help you look at it (spectators get free admission for the MVP tracktime event)
I used a little hand held vaccum pump and could hear the hiss a "mile" away when testing the valve for function. Replaced it because it was bad, still had an intermittent 32 and replaced the selenoid.
Now its back 3 years after the repair. I think its the source of my vaccum leak, I'll be checking the operation of the valve and replacing all the hoses soon.
I used a little hand held vaccum pump and could hear the hiss a "mile" away when testing the valve for function. Replaced it because it was bad, still had an intermittent 32 and replaced the selenoid.
Now its back 3 years after the repair. I think its the source of my vaccum leak, I'll be checking the operation of the valve and replacing all the hoses soon.
Thread Starter
Advanced
Joined: Jun 2010
Posts: 72
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Don't know where you are located, but when I first got my 92 I would get the 32 code anytime the computer checked the EGR operation. If you are near Road Atl, come on out next weekend and I can help you look at it (spectators get free admission for the MVP tracktime event)
I used a little hand held vaccum pump and could hear the hiss a "mile" away when testing the valve for function. Replaced it because it was bad, still had an intermittent 32 and replaced the selenoid.
Now its back 3 years after the repair. I think its the source of my vaccum leak, I'll be checking the operation of the valve and replacing all the hoses soon.
I used a little hand held vaccum pump and could hear the hiss a "mile" away when testing the valve for function. Replaced it because it was bad, still had an intermittent 32 and replaced the selenoid.
Now its back 3 years after the repair. I think its the source of my vaccum leak, I'll be checking the operation of the valve and replacing all the hoses soon.
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
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Cruise-In IV Veteran
St. Jude Donor '12
Yea, the LT4 doesn't have one because the cam has enough overlap to take care of it 
I'll let you know Monday what I find.
I'll let you know Monday what I find.
Instructor
Joined: Nov 2010
Posts: 107
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From: Terre Haute Indiana
STL94LT1, you sir, can pat yourself on the back. 32 is an EGR code. Per the manual, I only have to take EVERY NUT AND BOLT ON THE WHOLE CAR apart to get to it!! I think it started with "remove passenger seat, then spare tire, then the rear bumper, then the hood, engine, tranny and right hand mirror..." I joke, but it does say to lift the right side of the engine up to get to it... Fun, fun, fun...
