[jon_335]

I posted this in the Mechanical Maintenance section but it didn't get any response, so I'll ry my luck in this thread …

I mentioned this in an earlier rant post, but thought I would throw it out there as a specific post to see if anyone has had a similar experience.

The other day on startup, I had a surging idle, the car went into limp mode and was throwing P0221 and P0121 codes - throttle position sensor issues. I went through a process of turning it off and starting it up again several times and the problems persisted. As the engine warmed up, the idle calmed down, but still surged a little. And the codes were persistent.

The car is currently in the shop now. They reset the throttle response adaptations, which seems to have "fixed" it for now. If the problems come back, they are suggesting I might need a new throttle body. They tell me it could take several cycles to get the codes and surging idle again if it's truly a problem and not a random glitch.

I've owned the car for 2 years and have put ~18k miles on it. It currently has about 76k miles on it. The PO had a JB3 or 4 on it, but it didn't come with the car when I bought it. I've had very little problems with it over that time. In my searching, I've seen very little about bad throttle bodies or throttle position sensors on this car … mostly forum posts about the M3s and some 5-series.

Any thoughts on where to begin, without having to replace the TB? Clean the throttle body and MAF? Possible bad connections at the charge pipe, TB and intake manifold? Clean the sensors (if I can figure out where they are … maybe inside the TB)?

UPDATE: I have the car back and it seems to be fine so far. But I've only put maybe 30 miles on it since I got it back. And given other recent issues I have paranoia so every little bump, noise, blip freaks me out.

TIA!

[jon_335]

200+ miles later, everything appears to be OK. Seems that resetting the throttle adaptations fixed the issue. Given a recent string of bad luck with repairs, I've been hesitant to push the car too hard. But I'm getting there, driving her a little harder every day.

[jon_335]

Update: 500 miles later … on the way home from work, the car went into limp mode with reduced power/engine malfunction. Same codes as before.

I cleaned the MAF, which didn't fix the problem. So today I pulled off the throttle body and cleaned it. It was pretty dirty on the intake side, while the charge pipe side was fairly clean. When the this problem first appeared, it was right after having the cone filters cleaned and oiled. No codes as of now and she idles fine. Let's hope all is well from here on out.

Second update: next day … all is well so far and I'll be damned if the throttle response isn't improved. Kinda caught me off guard on my drive to work.

[Foxes]

Just a thought, have you tried walnut blasting your intakes? I would think carbon buildup would cause some hesitation and unsettled idling. Given that our cars are DI, I would look into getting it done at this age and mileage anyway.

[jon_335]

I had the intakes walnut blasted 2 years ago when I bought the car.

Besides, the idle was more than unsettled. It was as if someone was in the car continuously and quickly revving up to 1200rpm. If it weren't for the codes, I would have gone a whole different route with troubleshooting.

[Foxes]

How has your car been so far? Fixed the issue?

How many miles do you rack up a year on average? I'm thinking it's about time to send mine for a blast after sitting around 42k miles.

[jon_335]

Car has been great, with the exception of this issue and a string of cooling system issues (bad luck with timing). I bought the car with 57k on the clock in Feb. 2013. I now have 76k miles.

A couple days in, cleaning the throttle body seems to have fixed the issue and improved throttle response. That said, I'm not necessarily advocating cleaning the throttle body unless these codes present themselves.

[Ferruccio]

I am also getting p0121/0221 error codes and am wondering whether I should clean the throttle body. As it stands, I need to periodically reset throttle adaptation or else the engine gets terrible again. I'm wondering whether the flap might be resistant to moving freely or something.

[jon_335]

It seemed to help for me. And it's a fairly straight forward job, especially if you have cone intakes. Only four bolts hold on the throttle body and they're fairly easy to get to. Once you remove the TB, spray it down with TB cleaner and wipe some of the more stubborn dirt with a clean cloth. You're supposed to replace the gasket when you put it back on, but I didn't since I didn't have one handy and I was in a bit of a spot with needing to get the car back on the road.

Good luck!

[jon_335]

Posting an update since this thread is one of the few I've seen regarding these codes.

About a month ago, while running errands after I had returned from a 4-hour round trip, the codes popped up and the car went into limp mode again. Luckily it was a Friday so I had the weekend to continue the troubleshooting process.

Like before, I removed the throttle body and cleaned it. This time, no change. Ugh. So I unhooked the battery overnight hoping to reset the computer. That did the trick. I was back on the road. I wasn't taking any more chances so I bought a used throttle body on ebay. A couple weeks later I cleaned it and installed it. I cycled the ignition a couple times without starting the car to set some base parameters. Started the car up and all was good.

So far, everything has been good. It even seems to run better and growls a little more. Maybe the throttle body was in worse shape than I thought. If anything changes, I'll report back.

[pdm1230]

I am having the same issue...has your problem come back since you replaced the throttle body?

I brought mine to a local independent bmw shop the first time the errors came up and he replaced the throttle. Things were fine for a few weeks, but then after i hit a pothole the other day, i had the same thing happen. I got the car home and turned it off and on and things were fine. i noticed that if i try restarting the car immediately, nothing changes..but if i let it run for a while and restart it, the errors clear. Another interesting thing is that the error always seems to come up after hitting a bump or pothole. Not sure if something is loose or gets jarred. If there's a way to clear this immediately, I'd just learn to live with it for now, but that does not seem to be the case. I seem to be seeing it about once a week now.

[jbpitt]

I'm having a similar issue with the pot hole throttle body relationship. Did anyone come up with a solution? In my case, I hit a pot hole and my engine light came on. Took the car to the dealer and they said it was the throttle body. I ended up getting a replacement VDO throttle body, installing it (piece of cake) and driving for about 3 weeks until I hit a bump in the road causing the same failure modes. Thinking I got a defective part, I ordered a new throttle body and put it on. Hit a small pot hole and once again same failure mode. Happened on Easter Sunday too. Does anyone have any trouble shooting advice?

[jkoning]

Originally Posted by jbpitt

I'm having a similar issue with the pot hole throttle body relationship. Did anyone come up with a solution? In my case, I hit a pot hole and my engine light came on. Took the car to the dealer and they said it was the throttle body. I ended up getting a replacement VDO throttle body, installing it (piece of cake) and driving for about 3 weeks until I hit a bump in the road causing the same failure modes. Thinking I got a defective part, I ordered a new throttle body and put it on. Hit a small pot hole and once again same failure mode. Happened on Easter Sunday too. Does anyone have any trouble shooting advice?

Originally Posted by jbpitt

I'm having a similar issue with the pot hole throttle body relationship. Did anyone come up with a solution? In my case, I hit a pot hole and my engine light came on. Took the car to the dealer and they said it was the throttle body. I ended up getting a replacement VDO throttle body, installing it (piece of cake) and driving for about 3 weeks until I hit a bump in the road causing the same failure modes. Thinking I got a defective part, I ordered a new throttle body and put it on. Hit a small pot hole and once again same failure mode. Happened on Easter Sunday too. Does anyone have any trouble shooting advice?

I have the same issue some times but after a few cycles it goes away. Does it eventually go away for you?

[Tunafish]

Doubt you will get an answer.. That was the only post from user and a year and half ago..

[will1209]

Originally Posted by jkoning

I have the same issue some times but after a few cycles it goes away. Does it eventually go away for you?

Has anyone figured out a fix for this by any chance ? Going through this exact problem right now. Car hit a pothole and threw the throttle valve codes. If I turn it off and let it sit for a second it comes back to normal. Something about hitting the potholes triggers it and I’m super confused on what I should do.

[rabaa335d]

Guy, did anyone of your get to solve the problem ?
I have exactly the same problem, and didn't manage to solve it yet.
Please, if you did, let me know how.