Pre-Cat Oxygen sensor?

[ard]

Originally Posted by PHL08

. I let my engine light stay on for a while .

(editorial comment: Nice....)

Anyway, how long is "a while"

I ask because it is rare to have 2 sensors fail at once..but you could have had one fail, turn the CEL on...and 20k miles later the other fails...

[bawareca]

Originally Posted by ard

+1



The sad truth is, however, that after he spends $750, and the problem comes back, then there will be ANOTHER issue, that "most likely is what caused the sensors to fail" for more $$$. Nobody EVER gives back cash for the poor diagnoses they perform (present company excluded. )

Sad true!!! There are no more people interested in daignosing a sick car,just ones that are interested in collecting $$$,as much as possible.I always go out of my way to make sure that the customer(or myself) doesnt buy parts that he doesnt need.That is not the best way to make living,but it is what it is.That is the reason i dont run a shop anymore.If you have $2500+ monthly expenses in rent and utilities and 1 GOOD WORKER(now that sounds really funny if it was not tragic) you cannot afford to let any customer to leave the shop with a bill smaller than $500
But back on track,I am ready to bet a substantial amount that with 70 k miles both pre-cat 02 sensors are in great health,except if something really bad happened,but I dont believe so.

[PHL08]

Originally Posted by ard

(editorial comment: Nice....)

Anyway, how long is "a while"

I ask because it is rare to have 2 sensors fail at once..but you could have had one fail, turn the CEL on...and 20k miles later the other fails...

The light came on about 11 months ago, or about 10000 miles of driving. I know, probably not smart. My gas milage didn't suffer though, if that's worth noting. I reset the service light a few times and it would come back on within 100 miles or less. Before the visit to the shop, I reset the service indicator again and it came on immediately after startup.

[ard]

When you were doing these resets, did you pull any codes?

Pull codes when you can, post them. If you have a code reader that lets you look at short and long term fuel trims, post that too.

[PHL08]

I only use the INPA and NCSExpert tools (and very limited at that).

Prior to my reseting of the service indicator the other day before going to the shop, the INPA codes were as follows:


00 JBBF OKAY 1 Error Stored
A6CF 28

12 DME/DDE OKAY 3 Error Stored
2C9D E4
2A99 81
2DEB 02
29 DSC OKAY 5 Error Stored
5F45 A0
6EC8 A0
6EBD A0
5F13 A0
6D9E A0
36 TEL OKAY 1 Error Stored
D691 20

55 ISPB OKAY 1 Error Stored
D351 20

5E GWS OKAY 1 Error Stored
A83A 22

60 KOMBI OKAY 1 Error Stored
A3B1 20
62 MOSTGW OKAY 1 Error Stored
E18F 20

6E BFS OKAY 1 Error Stored
9E84 21

[ard]

Originally Posted by PHL08

I only use the INPA and NCSExpert tools (and very limited at that).

12 DME/DDE OKAY 3 Error Stored
2C9D E4
2A99 81
2DEB 02

These would be the ones that set a CEL, actually I think just the first two.

One is an O2 sensor HEATER code, which means the wire to the O2 is disconnected or the fuse is blown or the sensor massively failed.

Check all connections to the O2 sensors- pop them apart and reconnect them.

Second code i2a99 is an exhaust camshaft correlation. Im guessing a camshaft position sensor? The other issue can be a sluggish VANOS solenoid. Usually due to fouling of the solenoid due to BMWs horrific oil change intervals. Pop them out, flush/clean them, replace Orings.... at least on E39s.

Last one I dunno- seems like a battery issue. How old is you battery? Any charging/voltage issues?

[PHL08]

Battery is at least 2 1/2 years old (when I bought the car with 30,000 miles on it). I don't see anything in the carFax indicating a battery change, which doesn't mean it wasn't done of course but I see a lot of other standard routine maintenance logged by dealerships where the prior owner took it.

In the cold, it does *slightly* stutter when starting the engine, but otherwise I've had no indications of a bad battery otherwise. If it is original, it may be in need of a replacement, which also means coding the new one if I'm not mistaken, right?

[ard]

Almost surely original. No idea what ear or model engine you have....

Replace it with an idential battery and ALL you need to do is "register" it. And even that isnt essential. Youve got the tools to do it I think.

[PHL08]

Thanks for all the feedback. Car is an 08 3.0 model with an N52 engine. Other than sometimes the stuttering to start when cold, or after sitting a week unused, I haven't seen any other signs of battery weakness.

[ard]

These days the BMWs do odd stuff with voltage regulation and charging..I believe the voltage is allowed to drop too low after starting but during operation and this can throw off odd errors from some modules. just weird random modules with faults. You wont notice running issues but the stuff hanging on the bus will not be happy.

Just wag.