[410BN]

I've been having a pretty frustrating issue the last few years. Each time I replace the throttle body, it'll be fine for probably 1,000 miles or so, then I'll randomly start getting throttle body codes and it'll go into limp mode. A restart will usually fix it at this point. This will get progressively more frequent over the next 1,000 miles and eventually it'll get to the point where I start it, I have no throttle response, and the idle just hunts aggressively between 1100 and 1400 rpm.

I'll replace the throttle body and the cycle starts over again - it'll be codeless for about a 1,000 miles and then it starts again.

I'm on my 4th throttle body in the last 10k miles. All throttle bodies I've put on are just used OEM ones. I've also reset adaptations after each install.

At this point, it seems clear that the throttle body isn't the core issue.

Codes I've seen ordered from most recent to oldest spanning over the last few throttle bodies:
2CEC Throttle valve actuator, short locked
2CED Throttle vavle actuator, remains locked
2D09 Drosselklappe
2CF6 Throttle valve potentiometer 1, plausibility with regard to air mass
2CF7 Throttle valve potentiometer 2, plausibility with regard to air mass
2CFB Throttle valve adaptation valve
2CFD Throttle valve adaptation value missing
2CEE Throttle valve actuator, rough running
2CFE Throttle valve, continuous adaptation
2D61 Throttle valve, monitoring

Setup:
2007 335i
MHD race backend flash
JB4 map 3
BMS meth kit - dual nozzle
VRSF Downpipes
VRSF inlets
RB 17t turbos
SPEC stage 3+ clutch with SMFW

The car has about 92k miles on it.

[Podunk]

is the throttle being sent to DME, JB4, or DME through JB4? i would start with figuring that out, and then making sure pins didn't get mixed up when installing JB4, as well and testing the wiring circuits end to end for the throttle body, make sure you aren't getting any shorts, have proper resistances, and are getting proper voltages to the TB, if the harness tests out proper on the TB end with both key off and key on, ( just to make sure you aren't getting power where you are not suppose to) once pinouts on connectors are verified correct, and harness is verified correct, i would suspect faulty JB4 or DME depending on the signal path.

assuming you are using Genuine BMW Throttle bodies and not Duralast autozone or similar parts.

[410BN]

Originally Posted by Podunk

is the throttle being sent to DME, JB4, or DME through JB4? i would start with figuring that out, and then making sure pins didn't get mixed up when installing JB4, as well and testing the wiring circuits end to end for the throttle body, make sure you aren't getting any shorts, have proper resistances, and are getting proper voltages to the TB, if the harness tests out proper on the TB end with both key off and key on, ( just to make sure you aren't getting power where you are not suppose to) once pinouts on connectors are verified correct, and harness is verified correct, i would suspect faulty JB4 or DME depending on the signal path.

assuming you are using Genuine BMW Throttle bodies and not Duralast autozone or similar parts.

I wouldn't think it would be a pin mix up with the JB4 install, as it was flawless for at least 6 years before having any issues. I do have an INPA cable and a multimeter if I can track down exactly what voltages and resistances should be on which wires. A failing JB4 could be possible. Hopefully it's not the DME itself as that only has maybe ~20k miles on it since it was replaced under warranty to an MSD81 some years ago.

All of the throttle body replacements have been OEM BMW (used, though).

[Podunk]

how many used replacements have you installed? when you test out the harness try wiggling it too in random areas along it's travel from TB to DME/JB4, just to make sure, if you pierced the harness for the JB4 to pickup throttle it is possible moisture got into the wire and has corroded the wire, which would require replacement of the section of wire(s) affected or a harness.