A family friend of mine has a 97 tbird with the 3.8 v6 and it is throwing o2 sensor codes for every single o2 sensor. When they do that they read zero on the live data. But then other times they'll show readings. What would cause this? I haven't dug deep into it my first thought is something on the lines of a pcm or similar but I haven't looked thoroughly enough yet to be sure of anything.
97 t bird o2 sensor codes
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JHZR2
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O2 sensors are sort of like solid oxide fuel cells. They "generate" a voltage based upon oxygen ion transport.
What conditions do they show readings vs not? O2 sensors cant generate a voltage until theyre many hundreds of degrees. Starting and idling in the cold winter, this could take a long while.
So does it provide a reading after nice and hot but not when cold?
If so, Id guess heater circuits. Might they all be on the same relay/fuse/ecu control?
If not, then it may be more odd, but whats to say they didnt all fail? Might the car have been run a while with a CEL?
What conditions do they show readings vs not? O2 sensors cant generate a voltage until theyre many hundreds of degrees. Starting and idling in the cold winter, this could take a long while.
So does it provide a reading after nice and hot but not when cold?
If so, Id guess heater circuits. Might they all be on the same relay/fuse/ecu control?
If not, then it may be more odd, but whats to say they didnt all fail? Might the car have been run a while with a CEL?
Nick1994
$100 site donor 2024
My only experience with O2 sensors are with my 96' Chevy truck. When I bought it it had sat for over a year and it set a code for both O2 sensors. Being 16 I could only afford to replace one (I chose the cheaper of the 2) so I replaced it and the codes for both sensors went away after that.
Look for a common ground. Something is coming loose that is causing the PCM to not read them.
Usually if you have the Oxygen sensors go full lean or full rich, a bad MAF is the cause. But to also have the Catalyst Monitors wig out, there is a wiring issue.
Usually if you have the Oxygen sensors go full lean or full rich, a bad MAF is the cause. But to also have the Catalyst Monitors wig out, there is a wiring issue.
Originally Posted By: JHZR2
O2 sensors are sort of like solid oxide fuel cells. They "generate" a voltage based upon oxygen ion transport.
What conditions do they show readings vs not? O2 sensors cant generate a voltage until theyre many hundreds of degrees. Starting and idling in the cold winter, this could take a long while.
So does it provide a reading after nice and hot but not when cold?
If so, Id guess heater circuits. Might they all be on the same relay/fuse/ecu control?
If not, then it may be more odd, but whats to say they didnt all fail? Might the car
have been run a while with a CEL?
Yes they'll read 0.00 until warmed up but then will read voltage however voltage doesn't appear to be switching as it should and the codes it had were all for o2 sensors. Had 8 codes all for them
O2 sensors are sort of like solid oxide fuel cells. They "generate" a voltage based upon oxygen ion transport.
What conditions do they show readings vs not? O2 sensors cant generate a voltage until theyre many hundreds of degrees. Starting and idling in the cold winter, this could take a long while.
So does it provide a reading after nice and hot but not when cold?
If so, Id guess heater circuits. Might they all be on the same relay/fuse/ecu control?
If not, then it may be more odd, but whats to say they didnt all fail? Might the car
have been run a while with a CEL?
Yes they'll read 0.00 until warmed up but then will read voltage however voltage doesn't appear to be switching as it should and the codes it had were all for o2 sensors. Had 8 codes all for them
Originally Posted By: bdcardinal
Look for a common ground. Something is coming loose that is causing the PCM to not read them.
yup times eleventy.
maybe for testing, run an alligator jump wire between an exhaust hanger and chassis ground... 4 wire sensors have a ground or two but you can never have too many. The flaky ground you're getting could be through flexpipes and rusty iron manifolds.
I'd google 97 tbird bad ground and see if everything ends in some self-tapping screw in a rusty spot. 3rd gen camaros did this under the seat for example.
Look for a common ground. Something is coming loose that is causing the PCM to not read them.
yup times eleventy.
maybe for testing, run an alligator jump wire between an exhaust hanger and chassis ground... 4 wire sensors have a ground or two but you can never have too many. The flaky ground you're getting could be through flexpipes and rusty iron manifolds.
I'd google 97 tbird bad ground and see if everything ends in some self-tapping screw in a rusty spot. 3rd gen camaros did this under the seat for example.
This would be a situation where a shop should charge a diagnosis fee beyond looking up codes.
I agree its probably a wiring fault and that could take some time to find. $$$. I wouldn't throw parts at this one, that would be a real hail Mary pass
Originally Posted By: Vikas
Hold on a second here; ram_man works in a shop himself! May be he should be paying BITOG contributors for a diagnosis fee?
It's not at a shop. It's just some friend who the family who's fell on hard times and I am trying to help. But I have very limited time.
Hold on a second here; ram_man works in a shop himself! May be he should be paying BITOG contributors for a diagnosis fee?
It's not at a shop. It's just some friend who the family who's fell on hard times and I am trying to help. But I have very limited time.
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