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Discussion Starter #1
Hi all,

I've spent a few hours crawling forum posts to find some additional info specific to my car, hoping someone can shed a little light here!

I have a 2000 323i 5spd, which I believe makes it the M52 engine.

With stay at home orders in place, I haven't been driving. My EML came on a few weeks ago on a supermarket run and I went into limp mode. A few days later the battery was completely dead. I replaced it with a new one, everything seemed great. Since then no apparent power issues, but my EML did come on again.

Some stuttering when I try to accelerate, but idle more or less seems normal.
I did the adaptation for TPS (key position 2, hold accelerator for 10 secs, etc) and the EML cleared immediately. Car was driving normal for 2 days, and now EML is back with the same symptoms.

Based on all this I thought maybe the throttle body sensor(s) could be the problem. Any thoughts? Also, I tried to find those sensors on FCP and Pelican and wasn't able to. I've also read about the wiring harness being a problem, but that might be above what I'm capable of doing in my garage...

Thanks in advance everyone!
 

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2000 E46 323i, 3.0L and 2.0L Z3's
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The EML will have set fault codes. You should get the codes read and learn how to fix them before you start throwing parts at the car randomly. As the trans has gone into limp mode, there will be fault codes stored in the EGS as well. You will need a good scanner with BMW software to read all codes from all modules. Most scanners only read the DME (engine) codes.

Here are a couple of options:
- Foxwell NT530 with BMW software. Only buy from reputable sources. The cheap E-bay ones are knock offs and don't work. http://www.foxwelltool.com/wholesale/nt520-pro-scanner-with-bmw-software-installed.html

- INPA software on a old laptop and special cable. https://www.bimmerforums.com/forum/showthread.php?2184573-The-Z3-Diagnostics-Thread-Instructions-Experiences-Discussions-Experimentation
 

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Discussion Starter #3
The EML will have set fault codes. You should get the codes read and learn how to fix them before you start throwing parts at the car randomly. As the trans has gone into limp mode, there will be fault codes stored in the EGS as well. You will need a good scanner with BMW software to read all codes from all modules. Most scanners only read the DME (engine) codes.

- INPA software on a old laptop and special cable. https://www.bimmerforums.com/forum/showthread.php?2184573-The-Z3-Diagnostics-Thread-Instructions-Experiences-Discussions-Experimentation

Yeah, I realized I had to upgrade my diagnostics... I have always used PA Soft, but the cable I have with it doesn't work with INPA.

I do have INPA and I'm just waiting for my cable to get here, I ordered a few days before I posted here.

As I've never used INPA before I wasn't sure, but you're saying it will give me codes specific to the EML, so that sounds like absolutely the correct next move. Thanks!
 

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you need to describe your limp mode, as I just learned from a thread here not too long ago that it only applies to auto transmission
 

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Discussion Starter #5
you need to describe your limp mode, as I just learned from a thread here not too long ago that it only applies to auto transmission
I never knew that! Okay, here's what happens:

The EML comes on and the throttle response hesitates in the low RPMs. It won't usually allow me to take the RPMs up past 4.5k, and if I push the pedal down it fluctuates around 1.5k... as in up to 4k, down to 2.5k, up to 4k, etc. Won't go past that.


When I don't have an EML, no issues with response. I took the car to almost 100mph yesterday and the engine responded as normal.

Hope that helps make it clearer...
 

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Discussion Starter #6
Update: I never thought to try out PA Soft, but I just did and pulled some error codes. Here are the ones that seem like they could be a problem:

~IKE~
BF 191 "Internal fault, EEPROM checksum, coding incorrect/incomplete"

~DME~
64 100 "Control units, self-test"
A9 169 "Engine-throttle output-stage shutoff after diagn. error

And a code marked yellow, also on DME, 28 040 "Plausibility, signal, brake-light switch/pedal-travel sensor"


I'm going to try to find additional info on these codes now, but if anyone can give some guidance it would be much appreciated!
 

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Discussion Starter #7
I'm finding some info that might indicate a problem with the DME... Anyone with thoughts?
 

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2004 330Ci 85k miles
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Your 2000 323i engine is M52TUB25. The M52 was the prior generation engine in E36.

The IKE code looks scary but is common when coding with BMW Scanner 1.4, so just ignore it.

Focus your searches on those DME codes. Also, see if you can view DME throttle position live data in BMW Scanner 1.4.
There should be four sensors, two controlled by the throttle cable and two connected to the throttle valve. Each pair works in opposite voltage directions: 0-5V and 5-0V.

There is a kind of "limp mode" invoked by the DME when a throttle position fault is detected and the EML light is triggered. It's different than the AT limp mode but both result in reduced performance. You can read about the MS42 throttle control in this document, starting on page 51.
http://www.beisansystems.com/misc/SEIMENS_MS_420_ENGINE_CONTROL_SYSTEM.pdf
 

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Discussion Starter #9
Your 2000 323i engine is M52TUB25. The M52 was the prior generation engine in E36.

The IKE code looks scary but is common when coding with BMW Scanner 1.4, so just ignore it.

Focus your searches on those DME codes. Also, see if you can view DME throttle position live data in BMW Scanner 1.4.
There should be four sensors, two controlled by the throttle cable and two connected to the throttle valve. Each pair works in opposite voltage directions: 0-5V and 5-0V.

There is a kind of "limp mode" invoked by the DME when a throttle position fault is detected and the EML light is triggered. It's different than the AT limp mode but both result in reduced performance. You can read about the MS42 throttle control in this document, starting on page 51.
http://www.beisansystems.com/misc/SEIMENS_MS_420_ENGINE_CONTROL_SYSTEM.pdf
Wow, thanks for all of the useful info! I'm going to read through all of this today, and I'm also checking some of the more obvious things that I'm able to do (I'm a good hour away from the garage where I usually work on my E46).

Hopefully this helps to figure out the culprit quickly!
 

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Discussion Starter #10
I finally have a chance to update on this issue, hoping for a little extra guidance from someone more experienced before I spend unnecessary money.

I smoke tested and found a tiny vacuum leak in the lower intake boot, replaced it. No leaks from my DISA. Removed ICV and throttle body, spent a good hour cleaning both of them up. A good deal of buildup was in both. Put everything back together, got a good 100 miles before... EML again. I will say that the throttle response was greatly improved, just frustrating that I'm falling back into stage 1 limp mode (retarded timing and injectors, but can still reach higher speeds).

Before buying a new throttle body, I hooked up INPA and got some live data. I have the M52TU, so I have a throttle cable in addition to the motor actuated control. I wanted to adjust my throttle cable to see if that was a contributing factor. Here's a video of my live data, alternating between no pressure on the accelerator and fully depressed. Does anything look out of spec?


I was focused on the DKP-angle as I think this is the value for the throttle cable / butterfly. Please correct me if I'm wrong.

Worst case scenario, I'll pull the trigger on a new TB, but another set of eyes doesn't hurt. Thanks to all!
 

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Yes it was me that chastised a few for the all too frequent use of the term "Limp Mode" .

Yes there is also a limp mode (not to be confused with a common misfire and cylinder shutoff. NOT limp mode.)

Anyway the DK motor (electric throttle body) is very sensitive and has two paths one as a redundancy for checking the commanded throttle input VS actual. Should something go awry, the DK motor basically shuts down.
The car can be moved as the DME sees a commanded throttle input and uses the idle valve to full open as a means of gaining just a little bit of throttle so that the car can be moved.
If/when that happens, you are indeed in limp mode. Albeit for the throttle and not the transmission.
I've refrained from explaining such, owing to the general rarity of this one.
 

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Discussion Starter #12
Yes it was me that chastised a few for the all too frequent use of the term "Limp Mode" .

Yes there is also a limp mode (not to be confused with a common misfire and cylinder shutoff. NOT limp mode.)
Good to understand the difference, thanks.

Let me be more specific and say that I'm in "MDK Emergency Operation Mode 1", as per the Siemens MS420 manual. Symptoms as follows:

EMERGENCY OPERATION 1
• Activation of the EML warning lamp.
• MDK is deactivated, the throttle valve is opened mechanically by the springs and throttle cable.
• To maintain vehicle control, the MDK opening is compensated for by closing the idle speed actuator and retarding the ignition (engine power reduction).
• Engine power is further limited by fuel injector cutout. Emergency operation 1 limits the dynamic operation if one or more of the potentiometers fail. The engine can slowly reach maximum speed with limited power. The EML light will be illuminated to alert the driver of a fault.


To me this points to a failure of the potentiometer on the throttle body, but I'm honestly not sure of what those values should be in INPA (hence my video posted above). Can anyone identify values that are out of spec for the potentiometers or DKP angle?
 

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2004 330Ci 85k miles
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The DME trouble codes, I numbered them below, may be pointing to a failing DME or related wiring/connectors. #1 states the DME failed its self-test, #2 states the DME stopped providing throttle control because of some detected failure (probably #1), #3 states the brake pedal detection got a value out of normal range.
  1. 64 100 "Control units, self-test"
  2. A9 169 "Engine-throttle output-stage shutoff after diagn. error”
  3. 28 040 "Plausibility, signal, brake-light switch/pedal-travel sensor”
Things I would do.
  1. Pull off all DME connectors and carefully inspect all pins for damage, corrosion, fluid infiltration, etc. A bright light and magnifier will help.
  2. Inspect related wiring harnesses and connections for any issues.
  3. Remove and open up the DME and inspect for damage, corrosion, bad solder joint, blown component, etc.
 

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Discussion Starter #14
The DME trouble codes, I numbered them below, may be pointing to a failing DME or related wiring/connectors. #1 states the DME failed its self-test, #2 states the DME stopped providing throttle control because of some detected failure (probably #1), #3 states the brake pedal detection got a value out of normal range.
  1. 64 100 "Control units, self-test"
  2. A9 169 "Engine-throttle output-stage shutoff after diagn. error”
  3. 28 040 "Plausibility, signal, brake-light switch/pedal-travel sensor”
Things I would do.
  1. Pull off all DME connectors and carefully inspect all pins for damage, corrosion, fluid infiltration, etc. A bright light and magnifier will help.
  2. Inspect related wiring harnesses and connections for any issues.
  3. Remove and open up the DME and inspect for damage, corrosion, bad solder joint, blown component, etc.

1. One of the first things I did was pull the DME connectors. I saw one pin that had a little bit of residue on it, so I cleaned it up. Everything else looked okay there.
2. I also checked the harnesses, to my eye everything seemed to be in order but I'll definitely go through it again.
3. I've never opened up the DME, that makes me nervous! But I'll give it a shot, maybe I can identify some obvious damage.

Awesome info here, thanks!
 

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Discussion Starter #16
I'll check out the DME this weekend if I can, thanks.

Another question: when I had the throttle body out of the car for cleaning I noticed that the butterfly does not close all the way. I think that this may be normal... can anyone confirm?

Here's a video of the TB showing the space:

 

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Discussion Starter #17
Updates...

Since my last post, the EML issue continues to be pretty regular. I managed to score a brand new OEM throttle body and put it in last weekend, cleaned the ICV and replaced the ICV tube while I was there. Another awesome 70 miles... And the EML came up again.

I tried adjusting my throttle cable with DIS showing the values for throttle position, and it seemed to be in spec. Car started up great, solid idle. 7 minutes into the test drive, EML kicked on again.

I turned on INPA and pulled the following two codes:

"169 MDK output stage control after diagnostic failure"
"100 ECU seftest"



At this point, the only ideas I have left are replacing the ICV (unlikely) or calling it a DME failure and sending it in for repair.


I've checked my DME connections and all seemed well, but maybe I'll give opening it up a shot this time around...

That "100" code spooks me. Getting kinda nervous since I'm moving out of state soon and I can't drive it as-is... Really don't wanna have to tow.

Can anyone give some additional input to help me get this solved?
 

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Discussion Starter #19
In post #15 I suggested:
”A spare used MS42 DME with EWS deleted would be an easy way to swap it out and test.”
It is what I would try.
Yes, thanks Bali! I believe I have most of the software I would need to delete EWS, and I found Daniel_F's post where he shares his bin file for EWS delete. Is this something I could do myself by swapping in a used DME and flashing?

Or is there a trusted source for EWS deleted DMEs online that I could check out?
 
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