CEL P2096 P2098

[rkelly]

Hi Guys,

I will start by stating that all 4 oxygen sensors were replaced on my car ~ 1 year ago.

A few months back I started getting a CEL on my 986 Boxster. The code reported was P2096 (P2096 Signal Delay Time for Oxygen Sensor Ageing - Above Limit)

I cleared this error and after ~150 miles the CEL reappeared once again with the same code. I cleared it but it reappeared once again after ~100 miles. Unfortunately, this did not point me towards which of the 4 oxygen sensors was reporting the problem.

The fault reoccured 2 weeks ago (P2096). This time I decided to swap the 2 post cat oxygen sensors to see if that resulted in a different error code. IT DID! After 50-100 miles the CEL reappeared. This time the OBD II code was P2098.

P2098 Signal Delay Time for Oxygen Sensor Ageing, Bank 2 – Above Limit

My next step would be to replace the post cat oxygen sensor on Bank 2. Does anyone have a similar experience or any further suggestions on diagnosing the fault. Could the oxygen sensor fault codes be a red herring for some other problem with the exhaust system?

[Rockster]

rkelly said:

Hi Guys,

I will start by stating that all 4 oxygen sensors were replaced on my car ~ 1 year ago.

A few months back I started getting a CEL on my 986 Boxster. The code reported was P2096 (P2096 Signal Delay Time for Oxygen Sensor Ageing - Above Limit)

I cleared this error and after ~150 miles the CEL reappeared once again with the same code. I cleared it but it reappeared once again after ~100 miles. Unfortunately, this did not point me towards which of the 4 oxygen sensors was reporting the problem.

The fault reoccured 2 weeks ago (P2096). This time I decided to swap the 2 post cat oxygen sensors to see if that resulted in a different error code. IT DID! After 50-100 miles the CEL reappeared. This time the OBD II code was P2098.

P2098 Signal Delay Time for Oxygen Sensor Ageing, Bank 2 – Above Limit

My next step would be to replace the post cat oxygen sensor on Bank 2. Does anyone have a similar experience or any further suggestions on diagnosing the fault. Could the oxygen sensor fault codes be a red herring for some other problem with the exhaust system?

Generally if the converters are under performing there are specific error codes for that condition and while my info on those error codes is sparse I do not necessarily get the feeling the converters are at fault.

Also, there are error codes related to aging O2 sensors: slow response, weak response.

BTW, not sure where you are getting the descriptive test for those DTCs.

My references show:

P2096: Post catalyst fuel trim system too lean, bank 1.
P2098: Post catalyst fuel trim system too lean, bank 2.

Did you obtain any freeze frame data with one or both of the above error codes?

Did you get any other error codes like misfires?

Groping in the dark the errors can arise from an exhaust gas leak, #2 O2 sensor problem, and about a zillion other failures.

Since you replaced all 4 sensors a year ago I would have to wonder if the sensors you chose are sub-par or if perhaps if thread lube was used upon the sensor threads that the wrong type of thread lube was used.

But eliminate an exhaust system leak before you throw money at new sensors.

In fact, before you throw money at anything other than crawling under the car and checking for an exhaust system leak, throw money at an OPC.

You're probably money ahead by having a OPC diagnose this for you. There are probably 20+ test steps that eliminate IAT sensor, ECT, intake air leak, MAF, fuel pressure, and so on.

Sincerely,

Rockster.

[bobsan]

My money's on the CAT's. they've (it's) come loose inside container. Try hitting it with your hand see if can hear rattle. It takes around 80-100 miles of urban driving to trigger fault. You won't see any fault codes if driven on track.
The post O2 sensor gathers several over reads before lighting up cell light. The slower ( less throttle) you drive the earlier it'll trigger. Usually around 80-90 miles.

Edited by bobsan on Tuesday 9th October 07:52

[rkelly]

Hi Rockster/bobsan,

There have been no other fault codes reported and the car is running well. The sensors that were replaced ~1 year ago were done by my local (highly respected porsche specialist). They appear to have a bosch part number on them. Those sensors were changed out at that time due to similar error messages. He has told me I can leave it back with him for further investigation.

In the meantime, I have some free time this week so i'll get under it and check myself for leaks.

Incidentally, there was a rattle/buzz coming from the exhaust a few months back. At the time I was worried it was coming from one of the CAT's. I gave everything a good thump and it turned out to be just a loose heat shield.

The car passed its annual MOT test last week. I noted the following from the emissions test:
CO idle: Recorded Value 0.020 % Vol (Required limits 3.50 % Vol or less)
HC: Recorded Value 65 ppm (Required limits 1200 ppm or less)

From those values you would assume that the CAT's are working fine?

I guess this is all irrelevant though if I have misinterpreted the DTC's. To be honest I have been trawling the internet to find instances of Porsche P2096 and P2098. The most prolific hits have come from Loren on either RennTech or Rennlist.

He gets his information from the Porsche OBD II manual. Here is an example of one of his many posts on this topic.

http://www.renntech.org/forums/topic/18073-p2096-p...

I will phone OPC today and find out what version of the DME is on my car and confirm what the DTC's are.

Thanks a lot for your input lads it is greatly appreciated

Cheers,
rkelly

[Rockster]

rkelly said:

Hi Rockster/bobsan,

There have been no other fault codes reported and the car is running well. The sensors that were replaced ~1 year ago were done by my local (highly respected porsche specialist). They appear to have a bosch part number on them. Those sensors were changed out at that time due to similar error messages. He has told me I can leave it back with him for further investigation.

In the meantime, I have some free time this week so i'll get under it and check myself for leaks.

Incidentally, there was a rattle/buzz coming from the exhaust a few months back. At the time I was worried it was coming from one of the CAT's. I gave everything a good thump and it turned out to be just a loose heat shield.

The car passed its annual MOT test last week. I noted the following from the emissions test:
CO idle: Recorded Value 0.020 % Vol (Required limits 3.50 % Vol or less)
HC: Recorded Value 65 ppm (Required limits 1200 ppm or less)

From those values you would assume that the CAT's are working fine?

I guess this is all irrelevant though if I have misinterpreted the DTC's. To be honest I have been trawling the internet to find instances of Porsche P2096 and P2098. The most prolific hits have come from Loren on either RennTech or Rennlist.

He gets his information from the Porsche OBD II manual. Here is an example of one of his many posts on this topic.

http://www.renntech.org/forums/topic/18073-p2096-p...

I will phone OPC today and find out what version of the DME is on my car and confirm what the DTC's are.

Thanks a lot for your input lads it is greatly appreciated

Cheers,
rkelly

If the emissions numbers are well below the failure thresholds things are working pretty good, at the time.

As an aside: I have been nursing my 02 Boxster with a weak converter through emissions testing for several years now. Nothing illegal, I just know how to hold off the CEL for a while.

Even so the converter is working pretty good (most of the time) because the readiness monitors are set to complete and if the converter wasn't working well the converter related readiness monitor would be set to incomplete and I think that's enough to fail the car.

P2XXX DTCs are given in the SAE reference I have and I quoted from that book.

What is the MY of your Boxster? I'll see if I have anything specific on those error codes for your car.

Sincerely,

Rockster.

[rkelly]

Rockster said:

If the emissions numbers are well below the failure thresholds things are working pretty good, at the time.

As an aside: I have been nursing my 02 Boxster with a weak converter through emissions testing for several years now. Nothing illegal, I just know how to hold off the CEL for a while.

Even so the converter is working pretty good (most of the time) because the readiness monitors are set to complete and if the converter wasn't working well the converter related readiness monitor would be set to incomplete and I think that's enough to fail the car.

P2XXX DTCs are given in the SAE reference I have and I quoted from that book.

What is the MY of your Boxster? I'll see if I have anything specific on those error codes for your car.

Sincerely,

Rockster.

Hi Rockster,

The Boxster is MY 2003. I called the OPC in Belfast to see if they could offer a definitive answer on the DTC's. They checked their manual for my car and told me the following:

P2096 Signal Delay Time for Oxygen Sensor Ageing, Bank 1 – Above Limit
P2098 Signal Delay Time for Oxygen Sensor Ageing, Bank 2 – Above Limit

According to my records the following took place:
17th May P2096
20th June P2096
31st August P2096
10th September P2096 (DTC cleared and Post Cat O2 sensors swapped sides)
20th September P2098 (Bingo!!! It looks like the fault has moved with the sensor position change)

Unfortunately, It has reappeared this week however, this time I have both codes showing up!? wtf?
9th October P2096 and P2098.... contaminated sensor threads???

When I spoke to the OPC they were keen to get it in their workshop for some testing. I have it on the ramp in the garage at the minute as I have been doing a caliper refurb this week. It would have been handy to do the O2 sensor change while I was at it.

Any suggestions while I have easy access to the sensors? Maybe I should just take a chance and replace the suspected faulty sensor?

Thanks again,
rkelly

[Rockster]

rkelly said:

Hi Rockster,

The Boxster is MY 2003. I called the OPC in Belfast to see if they could offer a definitive answer on the DTC's. They checked their manual for my car and told me the following:

P2096 Signal Delay Time for Oxygen Sensor Ageing, Bank 1 – Above Limit
P2098 Signal Delay Time for Oxygen Sensor Ageing, Bank 2 – Above Limit

According to my records the following took place:
17th May P2096
20th June P2096
31st August P2096
10th September P2096 (DTC cleared and Post Cat O2 sensors swapped sides)
20th September P2098 (Bingo!!! It looks like the fault has moved with the sensor position change)

Unfortunately, It has reappeared this week however, this time I have both codes showing up!? wtf?
9th October P2096 and P2098.... contaminated sensor threads???

When I spoke to the OPC they were keen to get it in their workshop for some testing. I have it on the ramp in the garage at the minute as I have been doing a caliper refurb this week. It would have been handy to do the O2 sensor change while I was at it.

Any suggestions while I have easy access to the sensors? Maybe I should just take a chance and replace the suspected faulty sensor?

Thanks again,
rkelly

I double checked my reference:

SAE On-Board Diagnostics for Light and Medium Duty Vehicles Standards Manual 2010 Edition (HS-3000) (nearly 1000 pages worth!) and I quoted from it verbatim.

I could find nothing in the above reference that indicates manufacturers are granted permission by SAE/ISO to make the P2XXX codes propriety (unlike say P1XXX codes) but, and this is a big but, if an OPC with access to the official Porsche DTCs (error codes) and descriptive text et al specifically for your car tells you the codes are as you stated above, I'm not going to argue with the OPC or you if you decide to based on what you were told to replace the suspected sensors.

If I were in your shoes I'd go with what the OPC says.

It is a bit interesting the OPC wants to do a bit more testing, though. Know the cost before agreeing to it but it might be worth it to have this testing done and to know what the results/finding come from it.

Oh what to do with the sensors while you are there? I'd do nothing. If they are bad they are bad. If they have been contaminated with the wrong thread lube or improperly installed (touched with greasy/dirty hands) or have just failed prematurely there is nothing you can do short of replacing them that is going to help.

Sincerely,

Rockster.

[SkepticSteve]

Raised from the dead!

I have just managed to get a Durametric reader running and the code is 2098.

So can I ask did the OP cure the problem by replacing the sensor or the cat?
My exhaust rattles like a can of spanners and suspect loose left side cat, but car runs great!

[Rockster]

SkepticSteve said:

Raised from the dead!

I have just managed to get a Durametric reader running and the code is 2098.

So can I ask did the OP cure the problem by replacing the sensor or the cat?
My exhaust rattles like a can of spanners and suspect loose left side cat, but car runs great!

A rattling exhaust is one thing.

If the converter is rattling this is something else and in fact can be a smoking gun.

A rattling converter suggests the converter brick has come loose and this can affect how well the converter performs. For instance if being loose lets it fall out of position then exhaust doesn't not flow through as well and the converter's performance can be affected.

Now where confusion can arise is a sensor error comes about if the DME attempts to adjust fueling to compensate for the converter's sub-par performance and reaches its adjustment limit.

Bottom line is you still do not know for sure what the source of the problem is. Replacing the sensor is the less expensive path, at least initially, but if it does not need to be replaced, you've added to the cost of the repair by no little amount.

But you can throw a sensor at the error codes and see what happens.

Or you can ask the OPC what it advises and follow its advice. Or let it run its own diagnostics and make a diagnosis and then follow its advise/recommendation.

[SkepticSteve]

Rockster said:

SkepticSteve said:

Raised from the dead!

I have just managed to get a Durametric reader running and the code is 2098.

So can I ask did the OP cure the problem by replacing the sensor or the cat?
My exhaust rattles like a can of spanners and suspect loose left side cat, but car runs great!

A rattling exhaust is one thing.

If the converter is rattling this is something else and in fact can be a smoking gun.

A rattling converter suggests the converter brick has come loose and this can affect how well the converter performs. For instance if being loose lets it fall out of position then exhaust doesn't not flow through as well and the converter's performance can be affected.

Now where confusion can arise is a sensor error comes about if the DME attempts to adjust fueling to compensate for the converter's sub-par performance and reaches its adjustment limit.

Bottom line is you still do not know for sure what the source of the problem is. Replacing the sensor is the less expensive path, at least initially, but if it does not need to be replaced, you've added to the cost of the repair by no little amount.

But you can throw a sensor at the error codes and see what happens.

Or you can ask the OPC what it advises and follow its advice. Or let it run its own diagnostics and make a diagnosis and then follow its advise/recommendation.

Thanks for the reply.

My old girl is too old for OPC (and I'm too lazy to take it miles to get to one) so I let my local garage service it.
They fixed a similar code on my STR with a new sensor, so might just let them change this sensor.
The exhaust only rattles when cold, so suspect the cat is still working OK.

Don't know if connected, but this only started after I put V-Power in it for the first time!

[Rockster]

SkepticSteve said:

Thanks for the reply.

My old girl is too old for OPC (and I'm too lazy to take it miles to get to one) so I let my local garage service it.
They fixed a similar code on my STR with a new sensor, so might just let them change this sensor.
The exhaust only rattles when cold, so suspect the cat is still working OK.

Don't know if connected, but this only started after I put V-Power in it for the first time!

Shell V-Power? My 03 Turbo loves Shell gasoline that's about all I feed it unless I'm on a trip and then it gets fueled from any handy station offering top tier gasoline.

One guideline in the owners manual is if the engine reacts to the fuel to change fuel brands.

Also, you might have gotten some bad gasoline. Evo did a fuel test some years ago and found stale gas to be a real problem. From this it advised one to buy from a busy station to get the freshest gasoline. If the station you filled up from last time ain't very busy...

[SkepticSteve]

Rockster said:

Shell V-Power? My 03 Turbo loves Shell gasoline that's about all I feed it unless I'm on a trip and then it gets fueled from any handy station offering top tier gasoline.

One guideline in the owners manual is if the engine reacts to the fuel to change fuel brands.

Also, you might have gotten some bad gasoline. Evo did a fuel test some years ago and found stale gas to be a real problem. From this it advised one to buy from a busy station to get the freshest gasoline. If the station you filled up from last time ain't very busy...

The one I used was a brand new one, recently rebuilt and changed from Total to Shell.

I have to say it runs better on this new +Nitro V-Power! Much smoother as well.

I suspose she is just getting old and needs even more new bits to keep running!
10 years old and 92,000 miles now.
Might just have to replace the complete exhaust system and cats.

[rkelly]

I didn't really do any further investigation. Shortly after my last post I swapped the post cat oxygen sensors back to the original configuration and cleared the fault code. I also decided to start filling up at a different petrol station. The P2096 fault code reoccured once in ~1000 miles of driving and I cleared it again. I'm sure that one of the sensors is bad but I never got round to replacing it. Last month I traded it in against a cayenne S as the wife needed a bigger car. I was really sad to see it go. It had been in the family for 10 years.... after 109000 very enjoyable miles the car was still driving beautifully.

[SkepticSteve]

rkelly said:

I didn't really do any further investigation. Shortly after my last post I swapped the post cat oxygen sensors back to the original configuration and cleared the fault code. I also decided to start filling up at a different petrol station. The P2096 fault code reoccured once in ~1000 miles of driving and I cleared it again. I'm sure that one of the sensors is bad but I never got round to replacing it. Last month I traded it in against a cayenne S as the wife needed a bigger car. I was really sad to see it go. It had been in the family for 10 years.... after 109000 very enjoyable miles the car was still driving beautifully.

Thanks for the update.

I cleared the code and it has not come back yet.
I watched the sensor output graph and they were fairly close, so suspect it is marginal at the moment.
Someone told me to take it out and clean it, but I gave it some real welly the other day to get it really hot and hope that clears it for a while.

Thanks aagain - Steve