EML and DSC Light on E46

[pranu]

Sometime back I had a problem when my EML and DSC light came on along with the SES light. I immediately lost power (on 66 at that!) and couldn't do anything more than 40.

At that time I had 5 codes on the system.

118,119,120,121 and 175.

The 175 was fuel mixture too lean - and that was because some of the clamps on 6 hoses that connect to the engine (I dont know names) were lose and were letting in extra air.

So once they were tightened and the codes reset the car was back to normal. The other codes were something to do with either
1. Throttle Actuator Sensor
2. Throttle Potentiometer

The car drove well for about 2 weeks - but last night as I was getting home the same thing happened again.

From what I was able to find out it seems like it could be a bad potentiometer.

Have any of you folks had this issue - would my assessment be correct?

Is this a DIYable fix?

Thanks!

[SMOODY]

I have not experienced the issue you are describing, so I am not sure if the code you are seeing is in fact the source of the problem. The closest thing that I have experience to your problem turned out to be the infamous cam position sensor.

If the problem is a bad throttle potentiometer, then it is DIY fixable. The throttle is a drive-by-wire system. The throttle pedal and the sensor assembly are removed as module and are fairly simple to replace.

You might even be able to get it replaced for free. BMW replaced the the throttle assembly on the 3 and 5 series (not sure about the others) with an improved version because of complaints about the fact that it would get "sticky" when warm. There is a BMW TSB that tells the dealer to replace the part if the customer complains about the throttle sticking.

[pranu]

Thanks Smoody! Tried to look up details on the TSBs. There seems to be a separate problem about a "notchy" throttle which a lot of people seem to complain about - but that is not the problem I am facing.

I don't think I would call mine sticky either.

I guess I will take the car in to Curry's and have them check it out.

I notice that you are in Manassas - who do you normally take your cars to? (PM me if you prefer)

[SMOODY]

I usually do the majority of vehicle maintenance and repair work myself. If I had to take the car somewhere, I would end up in one of 3 places.

Warranty work - I have taken the 5er to BMW of Sterling. Mainly because it is convenient to my work location in Chantilly.

For a complicated project that would take too much time and effort to do at home - Manassas Motorwerkes.

Weird electronics issue that I could not resolve on my own, and was something that had the guys at Manassas Motorwerkes scratching their heads, and the vehicle is out of warranty. - I would take it to AutoAdvantage in Manassas. They are close by and have the big expensive diagnostic computer, although probably not really any cheaper than taking it to the dealer.

[pranu]

Just called the shop to figure out if they know whats happening.

The quick summary they gave me - Apparently the Throttle Body needs to be replaced - which is a long undertaking.

Supposedly an 8 man hour job! Involving removing the intake and then replacing it, making adjustments - mucking with the computer , etc, etc, etc.

They are supposed to call me back with full details.

Doesn't sound like this is going to be anywhere in the ballpark of tolerably expensive (forget about cheap!)

[pranu]

Alright so heres the final deal

If your car throws up the EML, DSC and SES lights. And goes into "limp mode" and the codes read 118,119,120,121.

The if your case is like mine then you have 2 problems

1. The EDR TPS (Electronic Throttle Control - Throttle Postion Sensor)
2. Secondary TPS

(And no the seondary is not redundant - as important as the first)

Apparently its a "delicate" job that needs to have lot taken out to get to these parts and lots of adjustment, computer code setting, etc...

The secondary TPS apparently does go bad - and the part is readily available at the dealers - but the EDR TPS - had to be specially ordered. So I guess I just had some bad luck that it went bad.

Sure hope this doesn't happen to any of you folks - but in case it does - hope this helps!

[tater tot]

I have the same EML/ASC problem with my E46, anyone has an idea how much it cost to fix it. Also, anyone here from San Diego that knows a reputable bmw fix shop? Thanks

[pranu]

I feel your pain!

Just so we are sure - your SES, SML and DSC lights are on and the car at times tends to go into limp mode - and the computer reads huge variances between the upper and EDR TPS sensors.

If that is the case then the cost depends on how bad your problem is.

We did a two stage fix in my car - to see if we can save some money.

Stage 1 -

Fix the malfuncitoning potentiometer in the Upper TPS (Throttle Postioning Sensor) before the throttle plates.
Fix - Replace the TPS (Part Number - 13 63 1 402 143) that costs about $80. About 4 hours of labor

Stage 2 -

This is required if the problem still happens after fixing the above - this would indicate that the EDR TPS needs to be replaced (slim chance - in my case it needed it). To replace the EDR TPS the intake venturis need to be removed and then put back again. Some adaptations (and I have no idea what the hell that means) need to be reset. The parts costs $305 (Part Number - 12 72 7 831 529). About 6 hours of labor.

Best of luck!