Help with my E39 please!!

[RicK87]

I recently bought a 2002 525i E39 a few months ago. Ran perfect for about 3 months and one night, I was driving down the highway and completely loss power. Car was still on but had little to no power even with the pedal fully pressed. I can’t get it over 10pmh, and it sputters. Limped it to the auto store to run the check engine light. Cylinder 6 misfire and Powertrain Control Module were the two codes read. I replaced the spark plugs but still nothing. I have also replaced the mass airflow sensor and a bad injector. Now it will run great when it wants. Drove it for about 30 min and ran fine the first 10, then went back to the same problems. Please help, I can’t seem to wrap my head around this problem.

[MarcoZandrini]

What are the codes you’re seeing? What scanner are you using? An obd2 scanner can read the engine computer (DME in BMWspeak) only. The car goes into limp mode to protect the engine and/or transmission from damage. Find a reputable indie shop that specializes in bimmers at www.bimrs.org.

[E39 Newbie]

When it failed did you see an error on the dash display? Like Failsafe Mode?

You'll need a good scan tool if you intend to keep this car. Whether you buy a used one from eBay, or buy a cable and download the software, doesn't matter. Without it you'll never get the thing running right.

After you have it, scan and report the codes. I was in your shoes a year ago. Luckily the friend who talked me into buying it is a BMW mechanic and has good scan tools. Otherwise I'd have pushed the damn thing off a cliff long ago.

FWIW, I had similar issues. I wound up replacing the MAF, hose connector, throttle body, you name it. It seems to me like everything on these cars seems to fail all at once.

[ramp]

Curious, my sons 525i occasionally goes into limp mode while driving. He'll stop restart and it's OK. It's a manual 5 speed so no tranny issues to worry about. The MAF sensor was recently replaced, it improved performance but still goes into limp mode with no codes to read. Interesting, I'll check throttle body and connections.

[E39 Newbie]

Curious, my sons 525i occasionally goes into limp mode while driving. He'll stop restart and it's OK. It's a manual 5 speed so no tranny issues to worry about. The MAF sensor was recently replaced, it improved performance but still goes into limp mode with no codes to read. Interesting, I'll check throttle body and connections.

There WILL be codes, although maybe not ones you can read with a generic scanner. You'll need a good scan tool (can be purchased off eBay, used, for a couple hundred), or use INPA (clunky interface IMO), or PASoft (requires Windows XP :-( ).

[balidawg]

There WILL be codes, although maybe not ones you can read with a generic scanner. You'll need a good scan tool (can be purchased off eBay, used, for a couple hundred), or use INPA (clunky interface IMO), or PASoft (requires Windows XP :-( ).

Agreed, there are codes if you have the right scanner.
BMW Scanner 1.4 (often called PA Soft) runs just fine on XP through Windows 10.
Get the cable and free software download here: https://www.xcar360.com/bmw-scanner-...de-reader.html
Get the device driver installer here: https://www.ftdichip.com/Drivers/CDM/CDM21228_Setup.zip