ReducedPowerE60

Hey everyone, I unfortunately bought a gorgeous 2008 550i E60 msport with 89k miles about 9 months ago before realizing these cars are absolute nightmares. I drive like a complete granny at all times because I'm scared the car will break. Recently I have been hitting limp mode and dozens of codes since April, all codes related to throttle position/throttle body and pedal set.

I drove the car about 700 miles last weekend without any issue, started the car up yesterday and instantly hit reduced power and every single light on the dash (brake/dsc/check engine/big engine icon/exclaimation mark, all of them) as well as the expensive chime sound BMW that haunts me in my sleep. Today I went and cleared the codes and the car drove normal for about 25 miles back home. I let the engine idle for about 5 mins then reduced engine power and very erratic engine idle started, 500rpm to 2,000 rpm with the car jerking around a bunch and no horsepower. I jiggled the connector at the throttle body as my research tells me the throttle body harness wiring goes bad often, I was able to start the car without the idle issue and drove it home although the CEL was still ON I did not have reduced power mmalfunction for the return trip home. I figured I needed to replace the throttle body wiring harness and connector. I cut and crimped in a new throttle body connector wire harness and plug since I thought that was the bad link.

After new throttle body wire harness now the car is even worse, idle is much worse, even more CEL codes this time and it will not rev past 1,800rpm let alone do a speed limit. Car is extremely jerky right now with these codes.

I couldn't find any accurate reference for the wire color combinations like i have so I put wires back into the same pins as before using the previous plug connector as a reference. I disconnected the battery, the I cut and twisted the two wire ends, then squished them together in the connector the kits comes with. Used the heat wrap and then bolted all the stuff back together.

old wires----------------------------------------------new wires

yellow/blue ------------------------------------------yellow/white
yellow black-----------------------------------------white/black
yellow/green----------------------------------------white/green
blue----------------------------------------------------green
yellow-------------------------------------------------yellow
yellow/black-----------------------------------------green/red

The engine runs much much worse now, I'm seeing the following codes.

p1637 throttle position control; control deviation
p1638 throttle valve position control; throttle stuck temporarily
p0120 throttle pedal position sensor A circuit
p0123 throttle pedal position sensor A circuit high input
p0223 throttle pedal position sensor B high input
p1062 VVT limp home request Bank 1 Full stroke not achieved
2cf1 CDKDVEL 0x2cf1 throttle valve actuator, position monitoring
2cf0 CDKDVER 0x2cf0 throttle valve actuator, control range
2cf8 CDKDK 0x2cf8 throttle valve potentiometer
2cf9 CDKDK1p 0x2cf9 throttle valve potentiometer 1
2cfa CDKDK2P 0x2cfa throttle valve potentiometer 2
2a6b CDKDVPMN 0x2a6b valvetronic power limitation

I have done a fair amount of troubleshooting and verified the engine has no sizable vacuum leaks. I ran a smoke tester machine at 9psi through the intake and replaced various o-rings and tighten everything down that was leaking smoke, its not vacuum leaking now so we can rule that out.

I don't understand why the car drives flawlessly some days and others hits limp mode right upon start up or limp mode as I'm driving with hardly any throttle input. It's driving me crazy to the point I made an account here to see if anyone has advice past sell my kidney & take it to a BMW mechanic.

Before I drive this car off a cliff is anyone able to share advice or has anyone actually fixed this issue where it didn't come back every couple days/weeks? I'm located just north of Seattle if anyone has recommendation of a indy shop to diagnose. Anyone local interested in helping lol prob not realistic but I have beer and pizza and could pay you for your time too.

seanjordan20

First I would start with checking the battery. How old is it? May need to get a new one and have it registered.

ReducedPowerE60

Battery passes all the scan tool tests.

Found the drivers side pressure valve had a tear in it, replaced that. Might help the smoke in the exhaust.

I ended up wiring back in the old wiring harness as I couldn't get the new wiring harness to work. The engine idles okay now but I don't believe its a long term fix. I'm guessing after I wired in the new harness there is some sort of programming or learning the computer needs to do with the new harness.

Have an appointment with an indy shop this week to diagnose and prob correct the wiring mess I made.

seanjordan20

There no programming for a harness. Are you sure the pins are correct

ReducedPowerE60

I copied the wires to the same pins locations as the harness that was removed originally.

Another thing I was considering is the length of the wire was longer on the new harness. The resistance of the wire would be different than beforeibefore it was longer length, this could cause the voltages to change enough for the sensors to get upset?

seanjordan20

Do you have a tester to check resistance. It's plausible but unlikely. It may not be getting a good connection at the pins.

ReducedPowerE60

I have a volt meter, no idea what ranges I should be getting at the pins, maybe if i knew the ranges I could test it past "does it have connection". Strange the new harness could have a pin issue from the start, I guess it could happen.

Any one happen to have the throttle body and pedal wiring diagram for the 2008 BMW 550i? wire colors seemed different with the original wires and the repair harness, maybe they faded and changed colors or something

dingolfing

https://www.newtis.info/tisv2/a/en/e...ttle-actuator/
https://www.newtis.info/tisv2/a/en/e...-pedal-module/

I believe there is a different E60 electrical wiring diagram in PDF form, which I do not have on me at the moment...

Jim165

I had the same issue long ago...my indy had to use two harnesses to replace the entire length of the wire back to the computer. Fixed it right up. Likely your entire harness is trash

ReducedPowerE60

The shop that fixed it told me they had to reset the throttle adaptations after wiring In a new throttle body harness.
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T​​here was another semi related issue, they mentioned the battery was a 95 amp battery when stock should have been 90amp. Again, the garage used software to reset the battery, If I wanna keep this car I need to get my hands on software it looks like!