1992 525 throwing trans prog code on a scan but cant clear it HELP

[bmwboy513]

Hey everyone im kinda new to this forum my names Bevon i own a 1992 525i all stock (for now) but a little while ago i got the trans program on my dash and it went into limp mode so i got it scanned and it threw pin 51 not connected ,ac compressor ,and the trans program error the guy cleared the codes and i started it it started perfect sounded brand new again not all sluggish ..but then when i turned it off and started it again it threw the codes ...i dont know what to do i have been told different thing by different people replace the TCM ect ect if someone can help shed some light on this sad story it would be greatly appreciated ASAP

[David Mc]

This sounds more like an electrical than a mechanical problem. When battery and/or alternator output goes low, it is common for it to show up as the car going into limp mode. If there was an active fault, the software would not have allowed the fault code to have been cleared initially. If it was my car, I would start by checking the battery voltage with a digital voltmeter, then have a look at the connectors and wiring harness, beginning with the ones related to the transmission which are under the car and/or toward the dirty end of the engine bay to make sure that they are all clean and firm. Your car is 22 years old now, so chances are you are going to see at least some verdigris and/or corrosion which may be responsible for the fault.

[bmwboy513]

thats what i was thinking Electrical but just want some more seasoned excperienced input ...thanks

[legoman67]

9 times out of 10 its the alternator.

[bmwboy513]

ok so i tested my battery to with a brand new tester with the key on acc car not started music playing it said 12.57 ....with the car started all lights on and music still playing 13.67 it fluxuated a little when when sub hits so could this be alternator oh ya another symtom is it runs perfect when it sits for like a day when i first start it then once it warms up it sputts

[legoman67]

transmission fluid level? last filter change?

Do you know what transmission it is? There were 2 automatics bmw used... One of which is the dreaded GM one. Replacing the transmission is just a regular service item as they get old...

[David Mc]

Do you have a ginormous amp installed in proximity to your DME or EGS by chance? If so, try pulling the fuses to the amp, then see how the car drives for a few days.

[bmwboy513]

To Lego how can I find out what kind of tranny I have and I have had the car for about a year now and haven't changed or check the fluid level thAts my bad wasn't aware ..and David if your referring to my sub amp it's only a 250w amp

[legoman67]

To Lego how can I find out what kind of tranny I have and I have had the car for about a year now and haven't changed or check the fluid level thAts my bad wasn't aware ..and David if your referring to my sub amp it's only a 250w amp

the only easy way i know is to get under the car and look at it. if it has 2 oil pans its the GM one.

[bmwboy513]

ok well today I replaced my coolant temp sensor 20 min job very simple it helped a little but it still lagges a little I really hope it not the alternator and I don't think its the tranny it shifts very smooth