2000 528i with numerous unexplained SES codes, no SES light.

[zalexnadre]

I have a 2000 528i sport auto trans (mfd. 10/99) with 191k miles. It runs nicely other than a sort of rattly vanos system and this issue it seems to be having now. It has smooth and good power and shifts nice and is an overall solid daily driving car. I have driven it on very long road trips without issue (other than the idler pulley locking up and throwing the serp. belt off, but that is unrelated.) Never been overheated, 2 owner, well maintained, original engine and transmission etc. Here is the big confusing issue I am having.

Since I bought the car the DSC light has been on non stop, but there is no SES light and never has been. I am going to try and sell the car soon but have to get it smogged for California registration (being a midwest car its never had an emissions test before.) Before taking it to the smog shop I decided to plug in the OBDII scanner just to see. Boy was I in for a shock. 17 codes popped up. 17 codes and no SES light?
List of codes found:
P1250
P0133
P1750
P1751
P1749
P1748
P0727
P0731
P0732
P0733
P0734
P1747
P1770
P1765
P0705
P0763
P1250
According to these codes bank one sensor one o2 is bad, my transmission is completely destroyed, and my car should not drive an inch under its own power. The car had a bad battery about a month ago that has since been replaced by a new one. It also has a newer alternator. I thought the majority of the strange transmission codes were caused by the bad battery so I tried to clear them. Upon hitting the quick clear button only 3 codes were actually cleared. (the o2, cooling fan circuit, and one fuel pressure regulator p1250 code that there were 2 of for some reason.) The transmission shifts quite well other than the occasional small clunk when cold (190k miles, it can't be factory fresh) and one small slip once when I put it in reverse and got on the gas immediately. I can't understand how the electronically controlled trans will shift and go into gear perfectly but the TCM shows that it is basically fried, multiple shift solenoids are bad, and almost every gear has an "incorrect ratio". To my knowledge the only module in the car to have ever been replaced was the ABS module which may have not been coded correctly (hence the DSC light always on with 4 good wheel sensors.) This situation is sort of boggling my mind. How can the car drive properly with all of these serious codes triggered? How can there be 17 current codes with no SES light ever? This makes me really want to just get rid of the car, but oh wait, it will never pass smog. I'm stuck with it. Some sense would be greatly appreciated. I don't have the heart to Pick'n'Pull the car as it drives so nice and is in wonderful shape inside and out. Thanks to California that will be pretty much my only option if I can't get this figured and get it to pass smog for sale. Any light into what is causing this or how to solve the issue (or issues) would be very greatly appreciated.

P.S. If anyone knows of any good shops around the Bay Area that can code modules well I will just 5 speed swap the thing (I have all the parts), replace an o2 and the electric fan and be done with it!!

[geargrinder]

Most likely the SES light has been taken out. Does it light up in a cluster test?

[zalexnadre]

No. I'm sure the SES light has been taken out as it doesn't not work during cluster test. Least of my worries at this point. Going to try a different cluster and check the trans fluid level. All I can think to do.

[geargrinder]

Uh. OK. "least of your worries" yes but you asked twice "how could I have all these codes and not have an SES light?". So thats your answer to that question.

Going to a different cluster is not going to help you with anything functionally wrong with the car - at least not these kinds of errors. The modules we're concerned with - engine, tranny, and ABS computers - all speak on high speed CAN-BUS to each other, so if they are having difficulties (and looks like they are) then the cluster can't really interfere or be a part of causing that.

BTW, unless you get a virginized cluster from somebody like blackknight530i, a swapped cluster will give you a 'tamper' light that will tell everyone that the mileage is wrong and you've tampered with the car (BTW is the tamper light on in this cluster? wouldn't be surprised if this car had more 'monkey business' going on if the SES light is borked).

Before going on - for future reference, if you're looking for help, just puking up a big ass long list of PeePee codes without the names/descriptions is gonna generally get you bupkis. As you see from only me replying here. There aren't a lotta guys who've memorized 5000 PeePee codes by number. The common misfire / O2 etc. codes yeah people will sometimes recognize but a big ass long list of more obscure ones like that? Useless to anybody who might want to otherwise help you. So for future ref, would be help if you took the extra time to put in what you've looked up for them. Otherwise here I am googling around the stupid numbers to try to help you. Assuming you've already spent time doing that, again, would get you a lot more people willing to help. At least if you posted up the ones that 'haven't gone away'.

Good that you reference the battery thing - yes indeed bad battery / voltage will give these cars fits, not the least of which the tranny computers for some reason. But those boxes will usually go into 'transmission failsafe' if the module is seriously unhappy and low voltage can cause that which sounds like you discovered. The fact that you don't get that and the car drives decently well is a good sign. Although you could check system voltage just in case your alternator is weak.

On the other hand, the deleted SES light is a really bad sign. Somebody else had this car, coudlnt' fix issues for whatever reason, and so they just smashed the SES LED or cut the traces to it. "Well maintained"... uh ok up to a point. Until somebody was like "yeah its got all these issues and it's gonna be $2000 to fix... or, I can just nuke the SES light?" "yeah great, just nuke the light please". That can often mean that they've borkled up / hacked a buncha other stuff as well. Car might be a fright pig of bad-PO-stuff down under there.

On the codes.

Most importantly, there's some speed related codes in there. If the tranny module isn't getting engine speed from the DME, and roadspeed from the ABS, it won't be able to work entirely properly, as its always using that data to do diagnostics as well as 'make decisions'. So the ABS/DSC problem may continue to be an issue for the tranny. It may very well be if you figure out the ABS/DSC problem the tranny will clear up a great number of those codes, including the gear-ratio stuff.

There's also a gear selector code in there however, as if it doesn't have proper gear shift information. However also something that shouldn't be too hard to diagnose/chase down.

On the short list before you start getting medieval on it:

1. I'd check a bunch of connectors for either bad connections, bad looking wires, and/or evidence of PO hackery. Clean them up w/ some contact cleaner (Deoxit recommended - radio shack or online...) after an eyeball. You should check:
   
   
   

   • transmission connector under the car,
   • tranny computer connections in the e-box also, look for any obvious wiring issues in there
   • connection at the gearshift in the center console.
2. And then the ABS/DSC thing. You say PO put an ABS module in, where'd that come from etc. If the same guy who was nuking SES lights in the dash was buying the ABS module, maybe its still a crappy one. Was it a junkyard item maybe? In which case who knows, maybe it came out of a manual car and therefore isn't talking to the tranny computer causing some of the issues. As far as I know, having the wrong coding in the ABS/DSC module doesn't cause trifecta though. Maybe I'm wrong. Or maybe its a bad junkyard unit. Or was it a 'rebuild'? There's some low-budget module rebuilders out there that have sketchy reputations. Then if you're really confident the module is OK then there's the other trifecta diagnoses to go through - not just wheel speed sensors but brake pressure sensor and steering angle sensor etc. Only about 1000 threads on ABS/DSC trifecta for info for you. BTW the ABS/DSC has its own codes, not sure if you've scanned that. Your generic Peepee coder device may not scan that module, I dunno.