check engine light
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check engine light I tried this question on the cadillac forum but did not get much info. I have a 2005 CTSV with 7K. B&B exhaust with X pipe, B&B headers and CAI
The car was diagnosed by the dealer with a bad 02 sensor infront of the cat on the passenger side. I changed both myself and the engine light is still on.
this was yesterday and and the light is still on,. I did some driving, maybe 25 miles, ran around town. Started and stopped the car atleast 10 times.
Someone on the Cadillac forum said to disconnect the battery and touch the 2 cables together and this would resest the PCM. Nothing happened, only had to fix the clock. The radio stations and all of my personal settings remained.
By the way, the car runs great! Any suggestions? I hate going to the dealer!
The car was diagnosed by the dealer with a bad 02 sensor infront of the cat on the passenger side. I changed both myself and the engine light is still on.
this was yesterday and and the light is still on,. I did some driving, maybe 25 miles, ran around town. Started and stopped the car atleast 10 times.
Someone on the Cadillac forum said to disconnect the battery and touch the 2 cables together and this would resest the PCM. Nothing happened, only had to fix the clock. The radio stations and all of my personal settings remained.
By the way, the car runs great! Any suggestions? I hate going to the dealer!
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
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From: Lake Zurich, IL
well... disconnecting the battery and leaving it overnight should reset the PCM ... but I'm not sure if Caddy's have any backup power for the PCM
On F-Body's there's a PCM IGN and PCM BAT fuse... pulling both for about 10 seconds w/the key in the run position clears the check engine light
Another option is to just have it cleared by a scanner... where are you located? Maybe someone is close by you and could help you out?
If the problem was the front O2 it should go away after a couple cold starts
Do you know what the exact SES codes were/are (was it only 1 or several? )?
Also kinda curious why you're changing the O2s? 05 w/7k should be warranty right? Let GM cover the bill heh
On F-Body's there's a PCM IGN and PCM BAT fuse... pulling both for about 10 seconds w/the key in the run position clears the check engine light
Another option is to just have it cleared by a scanner... where are you located? Maybe someone is close by you and could help you out?
If the problem was the front O2 it should go away after a couple cold starts
Do you know what the exact SES codes were/are (was it only 1 or several? )?
Also kinda curious why you're changing the O2s? 05 w/7k should be warranty right? Let GM cover the bill heh
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GM didn't want to warranty the 02 sensors with the exhaust and headers. I told them the headers and exhaust have nothing to do with the sensor going bad. They were dead set against it.
The codes they didn't tell me. Just that the o2 sensor before the cat was bad. I changed both just to be on the safe side. At first they diagnosed it as a miss. The car pulls like an animal and has no miss. That I would feel.
I live in queens NY, some said go to auto zone, they read codes for free. Maybe it needs a reset. I really want to knowif it will reset itself, and typically how long would it take.
I want to get a tune, but want to resolve this issue first..
The codes they didn't tell me. Just that the o2 sensor before the cat was bad. I changed both just to be on the safe side. At first they diagnosed it as a miss. The car pulls like an animal and has no miss. That I would feel.
I live in queens NY, some said go to auto zone, they read codes for free. Maybe it needs a reset. I really want to knowif it will reset itself, and typically how long would it take.
I want to get a tune, but want to resolve this issue first..
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
yea, autozone will read the codes for free... but not clear them
Have them read the codes and write them down... may be helpful
the SES light should turn itself off after a few driving cycles and/or cold starts
Post up in the eastern section to see if anyone is local to you... anyone with Autotap/HP Tuners/EFI Live can clear the codes for you I think? (not sure if they still use the same protocl in the 05 caddys... 05 LS2 motors don't use the same communication standards as older vehicles)
sux GM wouldn't warranty the O2 sensor.. but I can see where they are coming from...
as asked above... are you running an O2 Extension? If so the code was probably the O2 Heater .... common when running an extension w/stock sensors... but we really need the code to be sure
Have them read the codes and write them down... may be helpful
the SES light should turn itself off after a few driving cycles and/or cold starts
Post up in the eastern section to see if anyone is local to you... anyone with Autotap/HP Tuners/EFI Live can clear the codes for you I think? (not sure if they still use the same protocl in the 05 caddys... 05 LS2 motors don't use the same communication standards as older vehicles)
sux GM wouldn't warranty the O2 sensor.. but I can see where they are coming from...
as asked above... are you running an O2 Extension? If so the code was probably the O2 Heater .... common when running an extension w/stock sensors... but we really need the code to be sure
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The light went out today after driving about 45 miles this morning, I left the car for most of the day. Started it up and the light was off! 
Thanks for trying to be helpful in addressing the problem.
Great Forum!
What are o2 extensions? My setup in that area is all stock.
Thanks for trying to be helpful in addressing the problem.
Great Forum!
What are o2 extensions? My setup in that area is all stock.
