Please help diagnose computer trouble

[bimmer525]

Hi All,
I have a 95/525i with 151k miles on it. It been running well for about a year now. The first trouble I had was with the check engine light, which came on last december, I did the usual tests and determined that it was the O2 sensor. I *did not* replace the sensor, and was on a 1000 mile road trip. Early Jan this year, the battery drained, and I had to jumpstart the car (AAA), upon which the CEL reset and didnot light up with average driving in the city.

All of a sudden 4 weeks ago my alternator gave up and we had to put in a new one. After this I immediately went on a 1000 mile RT again with no trouble (but for excessive emission at times). Last week my CEL came on again for the O2 sensor. I took the car to a dealer and got the O2 sensor replaced. On my way back from the dealer the car stalled and the CEL came on again, this time with a 1222 code. I took it back and his initial diagosis was that he might have put a wrong part.

After replacing it once more the CEL again came on (but not stall) and I took it back to the dealer. After 4 days he tells me that the computer (??) is short circuited and it might be the reason the CEL trips. He says it could because of the previous alternator and wants $1.3k to change the computer. The check engine light is still on.

Can you all tell me what should I do and what could be wrong with the car? I know that the car is pretty solid and usually does last a long long time, could someone tell me how much long can I expect it to run?

Thanks in advance all.

[ryan roopnarine]

1222 could be a number of other things. o2 sensor can trip it, but it can be set off at any time on my car by a minor to major vacuum leak. the dealer might have just changed it because the code was registered. i'd do a serious vacuum leak check before you spend any more money. do you have reduced fuel efficiency right now?

[632 Regal]

i agree with the vacuum leak scenereo too, could be a tiny ass leak thats real hard to find or even intake gaskets or something. I doubt its the O2 sensor sine it was replaced and your having the same code.

edit: you have to disconnect the battery and cross the cables to reset the computer or the computer will still think that you have the same problem.

[bimmer525]

1222 could be a number of other things. o2 sensor can trip it, but it can be set off at any time on my car by a minor to major vacuum leak. the dealer might have just changed it because the code was registered. i'd do a serious vacuum leak check before you spend any more money. do you have reduced fuel efficiency right now?

The dealer says that even after repeated attempts he still got some CEL code.

He concluded that the previous alternator probably caused a current surge which shorted the computer inside.

Could he be right, he apparantely has checked for all leaks. He also mentioned that he might have put a wrong O2 sensor part on the car the first time he changed that, could that have caused some trouble? What are the implications of a shorted computer?
Thank you.

[ryan roopnarine]

The dealer says that even after repeated attempts he still got some CEL code.

He concluded that the previous alternator probably caused a current surge which shorted the computer inside.

Could he be right, he apparantely has checked for all leaks. He also mentioned that he might have put a wrong O2 sensor part on the car the first time he changed that, could that have caused some trouble? What are the implications of a shorted computer?
Thank you.


the crux of your problem lies in whether or not your o2 sensor is working or not. are you suffering from increased gas consumption right now? do you have an unstable or high idle speed for no reason? does your car's rpms undulate when you coast to a stop? can you smell a pecuiliarly high amount of gasoline or rich burn in your exhaust when warmed up (with your nose, not just standing behind the car)? if you none of these things is the case, there's a good chance that its not your o2 sensor. as your o2 sensor is New, and you aren't burning more gas, there's a good chance that its fine, and that the 1222 is from an o2 leak. if you are mechanically inclined at all, i'd go to walmart or such and buy two cans of the cheapest carb cleaner you can find. you take that and hose down every vacuum oriface or air intake gasket there is on your car with it running. i'd bet that you find it if you are aggressive, AND you thoroughlly get ALL of the orifaces, just doing most of them WONT CUT IT in your case. i have a 1222 in my computer right now. its the result of a massive air leak. my 02 sensor is fine. i have no reason to believe there's anything wrong with my computer.

[Brian C.]

Have you let anyone in on what your job is yet???

It's still burning in our minds......
Late night, rough territory, lots of $$$ to carry........I'm guessing you're a Sonny's delivery dude. :p

Brian C.

[ryan roopnarine]

Have you let anyone in on what your job is yet???

It's still burning in our minds......
Late night, rough territory, lots of $$$ to carry........I'm guessing you're a Sonny's delivery dude. :p

Brian C.

sonny's eh? ewww. i'm sure the problem in that situation would more likely be of people acting rednecky and trying to steal their orders without paying than being physically accosted and/or robbed. :D

[bimmer525]

are you suffering from increased gas consumption right now? do you have an unstable or high idle speed for no reason? does your car's rpms undulate when you coast to a stop? can you smell a pecuiliarly high amount of gasoline or rich burn in your exhaust when warmed up (with your nose, not just standing behind the car)? .

Well after the dealer gave it back to me I now get 1221 code today. He says he has seen other codes (I dont really believe him), he had the car for a week. His conclusion is the the computer is throwing out erroneous codes because it might have been shorted by the prevoius alternator.

There is considerable smoke coming from the car, its about 38F outside.
I do smell redisual gas from the exhaust.
I get around 18 MPG driving in the city.
The idle RPM is around 600.

How do I know that the dealer actually put a *good* O2 sensor?
I will get some carb cleaners, and see if the smell or smoke goes away.

I am kind of concerned that the computer might be shorted, could it really be shorted?

Thanks again.

[ryan roopnarine]

Well after the dealer gave it back to me I now get 1221 code today. He says he has seen other codes (I dont really believe him), he had the car for a week. His conclusion is the the computer is throwing out erroneous codes because it might have been shorted by the prevoius alternator.

There is considerable smoke coming from the car, its about 38F outside.
I do smell redisual gas from the exhaust.
I get around 18 MPG driving in the city.
The idle RPM is around 600.

How do I know that the dealer actually put a *good* O2 sensor?
I will get some carb cleaners, and see if the smell or smoke goes away.

I am kind of concerned that the computer might be shorted, could it really be shorted?

Thanks again.

i don't have the bentley or faults table near by. what is 1221? is that the o2 sensor code? i may have mixed the two up. you can create a number of faults by disconnecting important parts and trying to start the car, for example, i got a MAF code stored when i disconnected my MAF to get to my abs unit, and tried to start it. i'd do what jeff suggested and disconnect the battery, and see which codes come up by themselves. is the "gas" smell present when the car is at operating temperature? how bout the "smoke"? operating temp is 12 o'clock on the temp gauge.

[bimmer525]

i don't have the bentley or faults table near by. what is 1221? is that the o2 sensor code? is the "gas" smell present when the car is at operating temperature? how bout the "smoke"? operating temp is 12 o'clock on the temp gauge.

The smoke is present when I am idling at the lights, and I can smell the gas from that smoke also.
1221 is the O2 sensor.

How can I make sure that my computer is fine? I am kind of bothered about the computer breaking down when I am driving.

Thanks again