DSC, EML & Check Engine Lights On

[rpg]

Hi guys,

Some of you may be aware that I have been having some difficulty with my engine idle from a cold start; this turned out to be the dreaded vanos seals, but unfortunately the problems don't stop there...

During driving, these lights often light up, and they light up all at once; I cannot pinpoint a particular RPM or road speed it's occuring at, so it seems to be a random occurrence. If I turn off the engine and restart they may go away or either the DSC or Check Engine light will stay on. Just in case people are un-aware, DSC is Dynamic Stability Control and EML is a problem with the engine electronics. Also, power output is reduced when the EML light lights up.

I have a CarSoft diagnostic tool and it responded with this error relating to the DSC:

118 - Electromagnetic or mechanical influence on the wheel speed signals

There were no engine/DME fault codes stored in memory. I'm not sure how to proceed. Can anyone help or offer any advice on what to do next? Where do the wheel speed signals come from?

Regards,
Richard

[thejlevie]

CarSoft is decent, but it doesn't always yield valid data on newer BMW's. Having the car scanned by a dealer or well equipped indie would be a very good idea.

Each wheel has a speed sensor and those four signals are used by the ABS module for the ABS and DSC functions. That data is also used by the ABS module to produce the vehicle speed signal which is furnished to the rest of the car.

Problems in this area can be from a bad wheel speed sensor or a fault in the ABS module. A full up diag system should be able to tell you which wheel speed sensor is involved. Unfortunately, the ABS module can't distinguish between a bad wheel sensor and a fault in that wheel's interface within the ABS module. So replacing a "failed" wheel speed sensor may not fix the problem, but it is the first thing to try. If the problem winds up being in the module, ModuleMasters has a pretty good record of repair.

[rpg]

CarSoft is decent, but it doesn't always yield valid data on newer BMW's. Having the car scanned by a dealer or well equipped indie would be a very good idea.

Each wheel has a speed sensor and those four signals are used by the ABS module for the ABS and DSC functions. That data is also used by the ABS module to produce the vehicle speed signal which is furnished to the rest of the car.

Problems in this area can be from a bad wheel speed sensor or a fault in the ABS module. A full up diag system should be able to tell you which wheel speed sensor is involved. Unfortunately, the ABS module can't distinguish between a bad wheel sensor and a fault in that wheel's interface within the ABS module. So replacing a "failed" wheel speed sensor may not fix the problem, but it is the first thing to try. If the problem winds up being in the module, ModuleMasters has a pretty good record of repair.

Thank you very much for the quick and detailed response Jim.

I do hope it's just a speed sensor as I believe a replacement ABS module can be very expensive. ModuleMasters look to be experienced and ship worldwide. Definitely cheaper than a replacement unit from BMW.

Thankfully, I have a friend who works in BMW who can arrange a diagnostic for me, but I'll have to wait until the new year.

Once again, many thanks for your advice.

[rpg]

CarSoft is decent, but it doesn't always yield valid data on newer BMW's. Having the car scanned by a dealer or well equipped indie would be a very good idea.

Each wheel has a speed sensor and those four signals are used by the ABS module for the ABS and DSC functions. That data is also used by the ABS module to produce the vehicle speed signal which is furnished to the rest of the car.

Problems in this area can be from a bad wheel speed sensor or a fault in the ABS module. A full up diag system should be able to tell you which wheel speed sensor is involved. Unfortunately, the ABS module can't distinguish between a bad wheel sensor and a fault in that wheel's interface within the ABS module. So replacing a "failed" wheel speed sensor may not fix the problem, but it is the first thing to try. If the problem winds up being in the module, ModuleMasters has a pretty good record of repair.

Jim (or anyone else that can help!), I had this checked at a main dealer and it brought up the error code relating to the DSC module:

118 - DDE/DME doesn't fulfill torque request

I really have no idea where to start. Can anyone help?

[thejlevie]

That's a bit of a stumper. I've never heard of that that fault before and my only conjecture as to its meaning might be that the ABS module requested a power reduction from the DME to counter wheel slip and the DME didn't reduce power. But that's purely conjecture on my part.

[rpg]

That's a bit of a stumper. I've never heard of that that fault before and my only conjecture as to its meaning might be that the ABS module requested a power reduction from the DME to counter wheel slip and the DME didn't reduce power. But that's purely conjecture on my part.

Thanks for the response Jim. It actually makes sense.

Between the Carsoft and the main dealers description of the fault, it seems the "mechanical/electromagnetic influence" on the wheel speed sensors is actually the extra power produced from the supercharger. Since the DME is re-tuned by ESS, and the DSC module is looking for a reduction in torque to minimise wheel slip, the DME is not allowing/adapting to the requested torque reduction that the DSC requires.

At least I hope that's what it is! I'll avoid using DSC for the next few days, clear the errors on the DSC module and see if the problem arises.

Thanks again.

[rpg]

Update:

Problem turned out to be a faulty/stressed connection between the wiring harness from the DME to the throttle body housing. I cleaned the connection to the throttle body with some isopropyl alcohol and relocated the wire to give some extra length and to minimise stress and the problem has not occured since. So while the DSC/ABS was affected, it wasn't the cause. Thanks Jim for your help!

[98M3_4]

rpg,
Glad you fixed the most recent problem without any $$$ being spent.

BTW, what CEL code descriptions were you getting when you had the idle problems that were caused by vanos seals?

Thanks much

[rpg]

rpg,
Glad you fixed the most recent problem without any $$$ being spent.

BTW, what CEL code descriptions were you getting when you had the idle problems that were caused by vanos seals?

Thanks much

Unusually I was getting an idle control valve jammed open error, even after replacing the ICV (I thought it was just another problem!) the error code is still present. Upon reading Beisan Systems correspondence with BMW they mentioned that during diagnosis of the VANOS seals problem, they could hear the ICV smack open. I'm presuming that when I replace the seals, and clear the DME error codes, I won't see the error again.

Apart from that, no errors at all. I'm replacing the seals this weekend. I'll be creating a thread when I'm finished so keep an eye open!

[deep throat]

Can't tell you how useful this thread is....

To start with, what does "EML" stand for? The first time I had it on my 2003 M3 it ended up with my alternator dying out. Changed it, and now 2000 kms later it came back on again. TPS is changed earlier, spark plugs just changed. I'm suspecting a dying-out fuel pump or bad coils as the car buggers randomly at high and low speeds....But reading your earlier posts, it does make another possibility clear. The car has the M3 18" rims with 275/35/18 rear tires and 245/40/18 front ones fit by the previous owner. Could the wrong sizes be the culprit?

Any help is highly appreciated....

[rpg]

Hi there,

Sorry to hear about your troubles. EML is a German term which refers to "Electronic Throttle Control" aka Drive-By-Wire / Fly-By-Wire system. Unfortunately, it could relate to a number of different problems. My suggestion would be to get the codes read to try and single out the fault. I very much doubt your tires have anything to do with the problem.

I never actually updated this thread when I solved the problem. A few days after the update (fixing the throttle body connections) the problem came back. I spoke to a BMW Technician working for ESS Tuning in Norway and he mentioned usually when he saw this code, it related to either the Air Temperature Sensor or the Air Mass Meter. I replaced the Air Mass Meter (he insisted on buying genuine BMW) and the problem has not returned.

It also disabled the DSC and cruise control, since these also rely on the electronic throttle for activation. This is why the DSC light came on. The check engine light came on as I presume, un-metered air was entering the cylinders because of the faulty air mass meter. None of these lights returned after I replaced the air mass meter.

HTH,
Richard

[deep throat]

Thanks for the update mate..

The MAF was replaced 2 months ago with a genuine unit from BMW. What else could cause this in your opinon?

[alexkid]

Hey, I have a similar problem with a 540i and a few people have mentioned something about the throttle body cable issue, can someone take a few pictures of this particular area and highlight which area needs to be cleaned / what area is usually affected ...

[rpg]

I have only heard of the throttle body harness issue with E46/E39/E85 M54 owners; I'm not saying it doesn't exist for other electronic throttle BMW's, but I have no information for these models. In a lot of cases the wiring harness has been replaced and in some cases the throttle body assembly also. It has something to do with the electrical resistance of the wiring. Replacement, new harnesses and throttle bodies were updated to address the problem. This repair work was covered under BMW warranty.

Since most of these cars are now out of warranty, what is recommended is to clean the electrical contacts on the throttle body itself and on the wiring harness connection with some electrical contact cleaner and see if it resolves the problem. Only do this if you're sure that it's the problem. Get a diagnostic check done to make sure it's not something else; it will be related to the electronic throttle system but it may not be the harness or the throttle body assembly itself. If cleaning doesn't help the problem, then replacement of the harness and/or throttle body assembly may be necessary. Not cheap unfortunately.

I can take some pictures later if you like, but there is only one connection on the TB so it can only be that connection.

[deep throat]

Will try CRC on it tomorrow. Cleaning it wouldn't hurt....

What if you keep driving with the light on? Any future catastrophies?

[rpg]

I drove with the lights on for quite some time; ~30-50miles daily for a few weeks. They appeared intermittently and only affected the throttle when the lights were on. When they were active, the throttle was jumpy and acceleration was not as smooth as usual.

My main concern was damage to the cat. It is fine though as I passed my emissions test last week! Sorry I can't be of more help but even though I was aware of this problem I did get a diagnostic to see if it was something else. It didn't help in my case (because it didn't tell me it was the MAF!) but it might in your case. Best of luck.

[deep throat]

Thanks for all the feedback, that was priceless.....

[ErinG]

i am having the same problem with my 00 2.8. My code reader says it is "Throttle valve mechanically stuck" any ideas?

[Scany1980]

i am having the same problem with my 00 2.8. My code reader says it is "Throttle valve mechanically stuck" any ideas?

Same here. My DSC light has been on for quite a while now. I have rough cold starts in wintertime, the EML light and yellow "BRAKE" light has come up a couple of times and the car will barely move. Then after a shutoff or two it's gone. I've also had some misfire on cyl#5, but just hwen the cold start in wintertime was bad. Then I've also had the "Throttle valve mechanically stuck" code.

I was gonna check wheels speed sensors, but I dont have an ABS light. I guess I'll try to lubricate the throttle body wiring and see. Unless someone has a better suggestion? I dont want to throw parts at it.

[Specter325]

I created this eml problem for myself the other day when I was replacing the water pump on my 12/99 production 2000 528iT. I lost this little dude for a short while:

http://www.realoem.com/bmw/showparts...=64&fg=45&hl=3

Mounts on my fan shroud on the drivers side. Put everything back together and could not find it. Figured it was an air temp sensor or something like it and tried to run an errand. No way was the car making it out of the neighborhood. EML light comes on, the DSC light comes on and car will not go at all. Found the part in the under engine cover after tearing the shed where I keep the tools apart. Plugged it back in tonight and am charging the battery as the car has not be driven for a week now and I do not want that issue to have to deal with. Checked the codes and I have the 77 throttle body mechanically stuck code as well. Will see what happens in the morning.

[Specter325]

Battery was charged this morning and tried to start car with all codes erased. It still had same issue. Pulled the intake boots off and sue enough I could not open the throttle body with one finger. It was really gooped up with carbon. Pulled it off and it was pretty dirty. Cleaned it with a brass brush and some cleaner. Will get it back together and report.

[rpg]

Battery was charged this morning and tried to start car with all codes erased. It still had same issue. Pulled the intake boots off and sue enough I could not open the throttle body with one finger. It was really gooped up with carbon. Pulled it off and it was pretty dirty. Cleaned it with a brass brush and some cleaner. Will get it back together and report.

Good information; thank you for the update.

While you have the TB out, I suggest you clean the electrical connection on the TB and the wiring harness with some electrical cleaner. Let us know how you get on.

[Specter325]

Well cleaned everything up including the connectors and put it back together. A quick trip to the dealer for the $12 tube that has the side tube for the ICV, mine tore during removal due to age, and everything is back together and runs fine. No more roughness and the lights are off. Seems like it worked. Now we will see for how long.

[srikanthkv]

Hey my 2001 530 I has the same problem. Can you help me locate these connections under the hood?

[rpg]

Well cleaned everything up including the connectors and put it back together. A quick trip to the dealer for the $12 tube that has the side tube for the ICV, mine tore during removal due to age, and everything is back together and runs fine. No more roughness and the lights are off. Seems like it worked. Now we will see for how long.

Good news. I see it's over a month since you posted. How are things going now? No more problems?

Hey my 2001 530 I has the same problem. Can you help me locate these connections under the hood?

Hi there,

You need to remove all the airbox rubber boots that go back to the throttle body. It's pretty easy. By referencing the diagram below, start at the MAF (No. 1) and gradually work back towards the TB removing rubber boots (No. 3 & 7) until you reach the TB. Also, like Specter325, you may have a clogged/dirty TB. Clean the opening with some carburetor cleaner to loosen any dirt/carbon that may be stuck.

Looking at the TB, just above the opening to the right, facing the left, is the electrical connection. This is the connection that sometimes causes an EML error on the dashboard. Clean this with some electrical contact cleaner and re-fit, ensuring a solid connection.



HTH,
Richard