EML, Brake & DSC Light on

[pyo]

This has happened to me 4 times in the last 3-4 months, with 3 of them all occurring within this week. I picked up a 2004 Z4 with 37,500mi back in Feb2012. At this point in time, I have almost 50,000miles (daily driven)

1st 2 times happened at very low speeds. I was going over a speed bump and then out of now where the revs started bouncing up and down with the car in neutral and clutch fully disengaged. Restarted the car and issue was resolved. Didn't think too much of it. (Aug/Sep?)

2nd time happened last Sunday as I was going around the corner of a parking lot to exit, shifted into 2nd and car started doing this again. Restarted and issue was resolved.

On Monday, got the codes read by a friend who has all the proper cables/software. I would like to mention he did update my software from the original 2003/2004 to the 2006 version. He said there were no codes stored on the computer.

On Tuesday, with a help of a buddy, cleaned the ICV, DISA and Throttle Body.

Yesterday, after a solid 30 minutes of driving on the highway at 55mph+ I was navigating the local roads around 25-30mph in 4th or 5th gear when it occurred again. I was in the middle of traffic and couldn't pull over so I went ahead and restarted the car while in motion and everything was back to normal. After work, it took me over an hour in stop and go traffic to get home but didn't run into the problem again.

Today, on my way home from work going through the local roads around 30mph in 4th it happened to me again. As before, no where to pull over so I restarted the car while in motion and everything was fine. Proceeded to drive an additional hour in stop and go traffic without any issues.

Below is a video I took on the 2nd occurrence. http://www.youtube.com/watch?v=MSMOLNumur0&feature=youtu.be

I have recently replaced my battery in the past 2-3 months as it was still on the OEM battery and completely died on me. All connections are tight and no visible corrosion on the cables/connections.

Would like to resolve the issue myself if possible. Its been suggested that I change throttle position sensor but can't find a part number. Local dealership says it is actually included as part of the accelerator pedal/module assembly (P/N 35426858575).

Help would be much appreciated!

 

[bcworkz]

There's two throttle position sensors, throttle body and accelerator pedal, both are integrated into the respective assemblies. I wouldn't be in a hurry to blindly swap parts based on speculation. The EML is supposedly a separate issue from the brake and DSC lights. Curious they came on at the same time. Based on your tach in the video, it's idling like crap as well. I have to wonder if you overlooked something while reassembling after your bout of cleaning. OTOH, you were having issues beforehand.

You should get the codes read again, if the lights are on, there should be codes. Too many unknowns right now, codes will narrow things down, hopefully.

I could be wrong, as our cars might be geared differently, but 30mph in 5th is too slow for that gear. 4th is OK, but may not be good for long stretches. While low rpms are good for fuel economy, I firmly believe BMW engines like to be revved to high rpms frequently. They start complaining when denied this, they start acting up. An 'Italian tune-up' may be in order, though that's probably not the main problem.

 

[pyo]

There's two throttle position sensors, throttle body and accelerator pedal, both are integrated into the respective assemblies. I wouldn't be in a hurry to blindly swap parts based on speculation. The EML is supposedly a separate issue from the brake and DSC lights. Curious they came on at the same time. Based on your tach in the video, it's idling like crap as well. I have to wonder if you overlooked something while reassembling after your bout of cleaning. OTOH, you were having issues beforehand.

You should get the codes read again, if the lights are on, there should be codes. Too many unknowns right now, codes will narrow things down, hopefully.

I could be wrong, as our cars might be geared differently, but 30mph in 5th is too slow for that gear. 4th is OK, but may not be good for long stretches. While low rpms are good for fuel economy, I firmly believe BMW engines like to be revved to high rpms frequently. They start complaining when denied this, they start acting up. An 'Italian tune-up' may be in order, though that's probably not the main problem.

CEL never stays on after I restart the car. Nevertheless, friend hooked up his computer to the OBDII and there was a stored code (he did clear everything last time). It did mention the ICV. He went ahead and checked all the connectors he could get his hands on and crimped down the pins inside. Also reset the throttle adaptation via software.

on a side note, i think i do 5th gear in 30mph on that stretch of road to work only because it is downhill slope. otherwise, i agree too high of gear for speed. I too believe the car should be driven the way it was meant to be and she does get her legs stretched often. I just did some WOT highway runs and went through the local twisties (it was 55 F today, top was down). So far the issue hasn't happened again.

 

[biggsyZ4]

You may now have resolved this but I had a problem with the same symptoms as your video

Not sure of the reasons behind it but in the end, I had the throttle and a control unit replaced. Mechanic diagnosed it was either one of the main control units or the throttle unit. Throttle unit was cheaper so that was replaced, then changed the control unit which then knackered the new throttle unit so that had to be replaced again under the warranty of the part. Unfortunately, cost me in total about £800 to get it fixed.

The control unit was on back order from BMW so took a few days to come.

Rob