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Help with fault codes

1K views 8 replies 3 participants last post by  AWP 
#1 ·
Hi,
I am new to the forum and a first time BMW owner. I just took delivery on an 03 325i, E46, with M54 engine. The "Service Engine Soon" light came on after driving it for 5 minutes. I need help figuring this out. The codes it throws are:

P1085 Fuel control mixture lean (bank 2, sensor 1)
P1083 Fuel control mixture lean (bank 1, sensor 1)
PO174 system too lean
PO171 system too lean

The car has 113k on it and I have no service history so not sure if the O2 sensors have been changed. I am thinking it is acting more like a vacuum leak, but I would love other opinions. I am reading everything I can find about this car and plan on doing as much of my own repair as possible.

BTW, I also need to know how to reset the codes after I fix the issue. I did not have much luck with the search tool.
Thx,
Whit
 
#2 · (Edited)
The P0171/0174 codes are classic indications of vacuum leaks. Get the intake smoke tested. The car is more than 10 years old, and the various plastic and rubber hoses have had a tough life. The other codes may disappear after you find and fix the vacuum leaks. I bet the fuel pump is original. Do yourself a favor and replace it with a Siemens/VDO pump. Replace the fuel filter at the same time. Install either a Mahle or Keyser fuel filter.
 
#3 ·
fault codes

My son filled the car with gas last night and said the "Service Engine Soon" light went out after he started the car at the gas station. I asked him if the gas cap felt loose and he said he thought it did, so maybe that is all there is to it. However I thought it took 50 miles or so for the codes to clear, plus it seems there are other codes for the gas cap issue. I am still going to inspect the car of vacuum leaks and examine the DISA for issues.

In other news, I heard clank, clank, clank when my son started the car this morning. After 3 quick clanks, the engine sounded normal. Any ideas what this indicates?
 
#5 ·
I tore into the car today. Found a loose hose clamp on the intake side of the Maf and both intake boots had bad cracks. I cleaned the ICV which was stuck and examined the DISA which looks to be ok to me. It had no ORing but was put on with liquid gasket. I wonder if this means it had been changed before. I think I will leave it and reassemble with an O Ring.

Ordering parts and will report back once everything is installed.
 
#8 ·
I read you can put 12v in the disa connector to test it. Does anyone know which pin takes the + voltage. I would hate to burn out the DISA by getting the polarity backwards. I did do the test with my finger over the air hole, but that was inconclusive.
 
#9 · (Edited)
Bought a DISA Oring off ebay from eeskinazi and reassembled the car. I then reset the SES and so far after about 30-40 miles, I am not seeing any new codes. The engine idles slightly rough in the morning but that clears up quickly and it purrs like a kitten the rest of the time.

I will be changing the oil this weekend as I don't know what is in there from the previous owner (yea I know, I should have done this first). I will replace wih Valvoline SynPower 5w30

I bought a Mann fuel filter that I will install when the car gets low on gas. At some point I will get to the fuel pump. I keep hearing bad things about the auto transmission so I just have to cross fingers on that. I should probably at least check the fluid level in it.
 
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