Throttle Body, TPS, Vacuum Leak?

[Bellisimo1]

Hello All,

I just replaced the starter motor on my 2006 325xi wagon and after firing her back up I got a few codes all relating to the throttle body and its sensors: p0123, p0222, p1417.

The car runs, and seemingly pretty well, except I do hear a low growl or bog sound on low rpm's and the idle is poor. The other thing I notice is that a few seconds after the engine shuts off I hear a loud noise from the throttle body that sounds like it's closing back up. I don't remember this happening before.

I double checked the plug into the throttle body and I loosened and re-tightened the manifold bolts. I re-checked all plastic air box connections etc. I can't figure out what's going on.

Would love some insight or suggestions. Thanks in advance!

Mike

[MIKYZZ4]

First,
Clear ALL codes, then perform a short drive cycle.
Take note of codes that reappear, then post back.

[Bellisimo1]

Tried that, they came back instantly. The SES light is on, should be mentioned that sorry.

[jclausen]

if it was ok before the repair, then check your work

[MIKYZZ4]

Check and double check your wiring,
you must have disturbed something or accidentally cut some wires.

[Old525i]

All those codes are related to throttle position issues. Make sure your plugs are fully seated. Make sure no dirt got into the connectors.

[MIKYZZ4]

Yes, specifically check for bent pins!

[Bellisimo1]

Well, you guys hit the nail on the head. Two pins were bent inside the plug to the throttle body connector.

The good news is that I was able to straighten them out and get it all back together. The bad news is that once I did, the car wouldn't run. It started and then died after a second. I unplugged the MAF sensor and it ran. Plugged it back in and it died. Sort of weird if this was also broken but wasn't showing symptoms previously. I did leave the air box outside while waiting for parts on order and forgot about them, then it rained. I'm wondering if the MAF got damaged. But again it should've shown symptoms previously. Should I just order a new MAF? I've seen some pretty cheap ones out there.

[MIKYZZ4]

First try cleaning the MAF with CRC Mass Air Flow Sensor Cleaner,
demonstrated in this video:https://www.youtube.com/watch?v=o90KcZRz95U

If engine can run after cleaning>clear codes and perform a short drive cycle,
then perform a scan to reveal new codes.

Btw, if the MAF sensor ends up needing to be replaced,
do not cheapout and replace with just any cheap sensor.
BMW Genuine OE or OEM sensors should be used for replacements,
as cheap,counterfeit,aftermarket replacements can cause electrical gremlins to appear.
Here is an excellent supplier:https://www.fcpeuro.com/BMW-parts/325xi/Mass-Air-Flow-Sensors/?year=2006&m=20&e=2053

[Bellisimo1]

So I tried cleaning with the CRC stuff and no change. Bummer. Is it safe to say the MAF is the problem and needs to be replaced? It's not the connector by chance or something else? Just don't want to throw parts at this for no reason. I know when you unplug something and it runs, then plug it back in and it kills the car, that's usually a sure sign of where the problem is.

Also, I'm still dumbfounded how this could have not stopped the car from running while it was operating with bent pins in the TPS connector but once I fixed that, this thing acts up. There must be some override feature when the TPS isn't functioning properly that masked the MAF problem?

Thanks for all the input, it's been extremely helpful this far.

[Bellisimo1]

I replaced the MAF sensor and it didn't fix the issue unfortunately. So here is the order of events: car won't start, replaced the starter motor. Put everything back together, the car starts but sounds like it's sucking air and I get codes related to the TPS. You guys advised to look for bent pins in the connector of the TPS and voila that was the issue. I get that fixed and try to start the car but it won't run (it turns over then dies). Unplug the MAF sensor and the car runs, plug it back in and it dies. I replace the MAF sensor with a new one and the car still dies. I'm stumped. Could I have damaged whatever is at the other end of the MAF sensor line? Any suggestions of what to look for?

[relative4]

Given we've already seen one case of bent pins, I would re-check every electrical connector you've touched, whether or not it leads to the MAF sensor. Also look carefully for pinched, broken, or shorted/grounded wires.

[MIKYZZ4]

Remove rubber intake boots.
Inspect the rubber intake boots by squeezing them to reveal hidden cracks, replace with new.

[Bellisimo1]

Thanks for the replies, I figured I should go back and check all connectors. Bummer. I think I did a pretty good job of inspecting for cracks etc in the intake tract but I'll check again. I'm more inclined to think its electrical since the car runs near perfect and then totally dies when the MAF is plugged in but who knows.

[Bellisimo1]

So there is a breather hose right after the throttle body that I must have knocked loose when I went back in to get to the TPS connector. No idea how but I was just hanging there. So far, she's back in running condition without issue. Hopefully it stays that way for a while.

Thanks again for all the input.

Mike