Engine Problems: EML, Brake & DSC lights on

[pyo]

Last week while leaving the grocery store, I was shifting from 1st to 2nd gear when out of no where the EML light, brake light and DSC light came on. The engine RPM's kept oscillating from 700-1200rpm with the car out of gear and clutch disengaged. The car cannot be driven as I cannot get a steady acceleration. I was able to restart the car and the issue fixed itself.

My buddy with all the proper cables and software, hooked up to my OBDII however there were no codes stored in the database.

2 nights ago, a buddy helped me clean the ICV, DISA and Throttle body. It was a little dirty but not too bad. After cleaning it felt like the car was a little smoother.

This morning about 30 minutes into my drive into work (mostly highway until I get local), i was going about 30mph in 4th gear when it happened again. Same symptoms as before and could not be driven. I was in traffic and there was no where to pull over, so while rolling down the road I restarted the car and the issue yet again fixed itself.

Does anyone know what the issue could be? Since this occurs randomly and throws no codes, I haven't taken it to a shop yet.

[Finnegan]

Original battery? Even it not, I'd start there.

Check the connections for tightness/corrosion. Get the battery checked.

This is common problem with the battery, easiest to test for, and a quick fix if it is battery related.

[pyo]

Originally Posted by Finnegan

Original battery? Even it not, I'd start there.

Check the connections for tightness/corrosion. Get the battery checked.

This is common problem with the battery, easiest to test for, and a quick fix if it is battery related.

Just changed battery couple months ago with one from sears. Ill check the connections after work. Should I get battery tested at autozone? She starts up without hesitation on a cold start (car is parked outside condo).

Also read it could be MAF. Really hope that is not the case.

[Finnegan]

Originally Posted by pyo

Just changed battery couple months ago with one from sears. Ill check the connections after work. Should I get battery tested at autozone? She starts up without hesitation on a cold start (car is parked outside condo).

Also read it could be MAF. Really hope that is not the case.

Unlikely it's the battery if it's new. Just offering that as the symptoms described could be caused by it. I'd still rule it out.

Otherwise, could be the MAF as you said, or a throttle position sensor.

I'd also try to code reader again. Your buddy's reader isn't just generic ODBII, right, it's a full BMW scanner (like Bavarian Technic, P.A. Soft, etc.), correct? Not all codes that are BMW specific are read by all readers.

[pyo]

Originally Posted by Finnegan

Unlikely it's the battery if it's new. Just offering that as the symptoms described could be caused by it. I'd still rule it out.

Otherwise, could be the MAF as you said, or a throttle position sensor.

I'd also try to code reader again. Your buddy's reader isn't just generic ODBII, right, it's a full BMW scanner (like Bavarian Technic, P.A. Soft, etc.), correct? Not all codes that are BMW specific are read by all readers.

Correct, not generic. He does local coding for fellow enthusiasts in the area. he updated my car software to the 2006 models also earlier this year, it was still on the stock 2003 from factory.

[pyo]

looks okay to me. all connections were tight and did not budge when wiggled.

[gferil]

I second Finnegan's comment on the TPS, I had the same symptoms and it turns out I had a defective TPS. I think Beta had the same issue as well too recently and solved it by installing a new one.

[pyo]

Originally Posted by gferil

I second Finnegan's comment on the TPS, I had the same symptoms and it turns out I had a defective TPS. I think Beta had the same issue as well too recently and solved it by installing a new one.

Thanks!

Do you have the P/N by any chance? Quick search on zpost shows the z4m has 2, is this the same with the non-m z4?

[gferil]

Check post #5 of this thread:
http://www.zpost.com/forums/showthread.php?t=592278

[pyo]

Originally Posted by gferil

Check post #5 of this thread:
http://www.zpost.com/forums/showthread.php?t=592278

Thanks gferil.

I think that P/N is M specific though. I emailed getbmwparts.com and was given this #35426858575

Hi Kenneth, thanks for your interest. The throttle position sensor for your vehicle is actually included as part of the accelerator pedal/module assembly:

Replacing the TPS with this should potentially resolve the issue right? Does anyone have a DIY on it? I am curious if it is in the same position as the M.

[ZStig]

I had an issue with the throttle position sensor too. on the M, its in front of the engine held on by 5 star bits IIRC. Once you have the replacement part in your hand its easy to find it on the engine. the TPS in the BACK of the engine is a PITA and more expensive. front one is like $35

[beta]

Same here, got the part number from gferil and it fixed everything. Took 5 minutes to replace, and 4 of those minutes was finding a screw driver short enough. Hope it works for you to OP.

[beta]

Mine happened also when the battery was going south, I think gferil also had run down the battery.

If this fixes it for you, then we know with a fair degree of certainty that a low battery condition can fry the TPS.

[pyo]

My buddy (local mechanic that fixes cars on the side) keeps telling me there is no throttle position sensor for the non-m Z4's.

He read the codes again and it mentioned the idle control valve. He checked all the connections that he could get his hands on and crimped down the pins inside the connectors. Also reset the throttle adaptation via computer (local programmer to).

I will post if it occurs again.