21 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHNew owner chasing CEL
Leading reported evidence
Check 4 connectors and they are good
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
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Read evidence and context
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Discussions that performed work without a confirmed outcome
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Leading evidence: 'Check 4 connectors and they are good' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Adjust therefore the maf is likely not completely shot' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
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Performed · outcome unconfirmed · Original poster
I disconnected the battery for a few hours and now the O2 sensors are communications with the car computer.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed · Original poster
I installed pre-cat Bosch 02 sensors on both banks.
Adjust therefore the maf is likely not completely shot
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion · Original poster
Unplugging the MAF while the car is running will cause the engine to stumble and then adjust therefore the MAF is likely not completely shot.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
21 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Hi, new owner here. 1999 996 with 63k. After a PPI I had a reputable indy shop in Portland, OR do some work on the car before taking it home to Washington. Work included fluids, spark plugs and resealing the valve cover gaskets on both sides. On the drive home the CEL came on. I�ve since reset it and it�s thrown the same codes:
P0134 Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Interruption of Signal
P0154 Oxygen Sensor Ahead of Catalytic Converter (Cylinders 4 - 6) - Interruption of Signal
P1115 Oxygen Sensor Heating 1 After Catalytic Converter - Above Upper Limit
P1119 Oxygen Sensor Heating 2 Ahead of Catalytic Converter - Below Lower Limit
I cleaned the MAF. Unplugging the MAF while the car is running will cause the engine to stumble and then adjust therefore the MAF is likely not completely shot.
I tested crankcase vacuum by removing the oil cap while the car is idling. The engine runs ruff with the cap off and returns to normal with the cap on.
I have not tested for an intake manifold leak yet. I'm not sure what hose to open to test this.
The car has an intermittent rattle in the driver�s side exhaust that I believe is from a loose internal muffler baffle. Not sure if this could be linked to the CEL issues?
Any thoughts would be great. Thanks!
^^^^
That rattle could be the Catalytic Converter and quite possibly, the source of your CEL. Personally, I'd inspect the Cats...
I had a Catalytic Converter on one of my RX7's internally break apart and pieces made their way all the way through the muffler and to the tailpipe.
And...hopefully the experts will respond with some additional information and help.
Mike
Check if they have forgotten to plug in your O2 sensors. The connections are on the left and right side of the intake airbox (may need to remove the airbox to check the right side if memory serves).
I checked all 4 connectors and they are good. Gray to gray and black to black. Upon further inspection of the 02 sensors I noticed a small gash in the driver's side pre-cat sensor that looked like it might have been recent. Perhaps the shop mangled the sensor when removing the exhaust for the valve cover job? Would this wreck the sensor and cause error codes on both banks??
Yikes. It may generate the codes for one bank but not the other (unless the precat O2 sensor on the other bank looks like this as well).
Do you have Durametric?
You should also verify the resistance of both pre-cat sensors (all of your codes are for the pre-cat sensors)
https://www.renntech.org/topic/51759...comment=292721
I don't have a Durametric. I just picked up the car and have a simple code reader. I can check if it has 02 readings when the car is running.
Thanks for the tips Ahsai!
Wow, they butchered that sensor. I would think this would have been noted had it been like that before. What shop did the work? I'd send them a picture and ask.
I have a new sensor on the way to replace this one. I already sent the shop a note. I've give them a chance to reply before naming them.
Using my code reader I can see that two of the four sensors do not change voltage at all, even after the car warms up. I believe that these are both banks, pre-cat.
I installed pre-cat Bosch 02 sensors on both banks.
After installing the Bank 2 (smashed) sensor the following codes were cleared: P0154, P1115, P1119. The remaining code was:
P0134 Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Interruption of Signal.
After installing the Bank 1 sensor I cleared the remaining P0134 code and went for a 30 min drive. The car ran great idle was smooth and NO CEL cam on.
This morning I drove the car again and the CEL light came back with a
new code: P0131
O2 Sensor circuit low voltage bank 1 sensor 1. Looking at the live data I see that there is ZERO voltage going to 02B1S1.
Why would I all of a sudden have zero voltage in the 02 sensor? Zero at idle, warm and running.
few ideas....
1. Wiring was not secured and melted to the exhaust?
2. Defective sensor
3. Another new issue. Some cars have built in programming so when the code sets the DME stops watching the known bad sensor and substitutes it for know good data. Reset the code and see if it responds shortly after.
One suggestion - don't just clear the codes, reset the ECU/DME entirely. Disconnect the battery negative lead for about an hour. You really need to do this after replacing O2 sensors. It will return all ECU/DME settings to default. Then go for a drive so the ECU/DME can re-learn all the O2 sensor values feedback and can adjust to new 02 sensors.
^^ I would second this - I had a situation where I got a CEL, subsequently did a bunch of work to address the code(s), and although everything spec'd properly the codes/CEL remained. It wasn't 'til I did a hard reset that they went away and remained away. In addition to disconnecting the battery, when you do, touch the two loose leads together for a second. Good luck.
WARNING
what he is talking about is disconnecting
BOTH
battery leads from the battery...the
negative
AND
the
positive
leads from the battery and then touching the two together.
Thanks DBJoe996!
This seems to have fixed the problem. I disconnected the battery for a few hours and now the O2 sensors are communications with the car computer. I'm seeing voltage where before it was 0.00. No CEL for the time being. The battery leads are not long enough to touch to each other so I didn't even try that part.
I'm chasing this very own issue and i'm down to the last suggestion of disconnecting the battery. I assume that I would have to do the drive cycles to get the readiness flags corrected?
If your exhaust rattles don't discount the cat converter.I have one where the substrate came loose in cat ,the whole assy became detached from internal mount .Depending whether I accelerated or stopped the cel light would come on .Looking inside it was clear the cat was defective.
This is a source reference. Confirm exact model applicability in the original material.
