diagnostic link connector MIL wont go out

[evertonfc]

I have been having problems with my 2001 E53 for a long time.
If I don't run the engine for a day or so then it won't start.
Turn the key and it just clicks. attach a booster battery and it starts first turn of the key.
Reading the forums it seems I should have somehow registered this battery with the ECU when I bought it 3 years ago. I bought the battery because of the starting problems. I had the battery checked by the parts supplier and they say it is fine (i think they sold me the battery with insufficient CCA, as there is another battery with higher CCA available for Canada).

However, as the battery dies at the slightest excuse it is causing me some problems with the MIL.

Last week i fixed the window carrier and during the 40 minutes or so that took with the door open the battery was absolutely flat. i.e. it didn't even do the usual click click sound. (it has NEVER turned over slowly, it runs or clicks).
I boosted the battery which required the booster pack to be attached to the car for a few minutes before it turned over.
The MIL has not gone out.

Using a Scantool OBDII laptop software i cleared the codes (24 of them from incorrect system voltage to incorrect gear ratio in all 4 gears, none of which are genuine i'm certain as it has done this before).
After repeated attempts to erase the codes, i.e. codes cleared but then returned immediately the engine started i called a friend who has the all singing all dancing SnapOn OBDII scanner.
He erased the codes but the MIL still wont go out even though the snap on has confirmed there are no codes stored.

It seems there might be a 20 pin DLC in the engine compartment that needs to be accessed too.

using the VIN analyzer the car was built 2000/10/06 which i think is October 6th and so probably too late to have the 20 pin connector. In any event I can't find one.

So, can anybody tell me the location of the DLC in the engine compartment.

Does anybody have any insight into erasing the MIL?

Typically, I have a buyer for the car but have to get it emissions tested first, which can't be done with the MIL on.

Any help at all is greatly appreciated.

[Qsilver7]

You don't have a 20 pin DLC based on the build date you gave....that's why you can't find it. The engine bay DLCs ended with the 9/00 build date for the e39/e53...and with the 6/00 build date for the 3 series. The e38 & Z3 are the only models at the time that still received the engine bay 20 pin DLC due to them being near the end of their production run.

You also took the battery registration wrong, too. It's the new gen BMWs that have iDrive that require battery registration. The e65/e90 models have the BSD communication bus, then starting with the e60 in 2004...each new model received an IBS (intelligent battery sensor) and the battery info is communicated over the LIN bus.

The e53 has neither the BSD nor LIN...or IBS...it falls under old generation BMWs where you can just replace the battery ( correct size of course) which would be a 49/H8 battery class size.

[evertonfc]

Thank you.
I will get the Snap On Solus scanner to stop asking for the 20 pin connector.

Do you have any idea why the MIL won't go out or the battery has never held a charge longer than three days since it was installed?

The battery warning light has never come on and after posting i replaced the window carrier (20 minutes with a little bit of miniscule raising and lowering of the window) and again the battery was so flat I had to use another car to jump start it.

[wpoll]

Originally Posted by evertonfc

Do you have any idea why the MIL won't go out or the battery has never held a charge longer than three days since it was installed?

The battery warning light has never come on and after posting i replaced the window carrier (20 minutes with a little bit of minuscule raising and lowering of the window) and again the battery was so flat I had to use another car to jump start it.

The "battery" warning light doesn't indicate anything to do with the battery (other than it's no longer being charged) - it actually indicates that the alternator/regulator output has fallen to below the voltage output of the battery. This usually indicates a total failure of the charging system.

But you say you don't have that, so assuming the battery is being charged properly is possible you have what is called a "parasitic drain" - something is pulling large amounts of power from the battery even when the car is off. This is not unknown on the e53 and can be caused by the A/C fan speed control resistor unit, the stereo and a few other common items. It can be tracked down by isolating the various circuit by pulling key fuses while monitoring the drain on the battery.

Coming back to the battery charge for a moment, it's worth pointing out that it would take a pretty powerful charger at least 8 hours or more to fully charge from flat a large battery like the one in the e53. A quick drive around the block after jump starting it isn't going to do it. I wouldn't be worried by the battery condition unless its failing quickly after a good long full charge (on an external charger).

Or a 500 mile drive....

[evertonfc]

i took it for a 40 minute drive on the highway yesterday and no problems starting today.

That still doesn't explain why the MIL check engine light won't go away.
Has anyone come across this before?

[wpoll]

Originally Posted by evertonfc

i took it for a 40 minute drive on the highway yesterday and no problems starting today.

That still doesn't explain why the MIL check engine light won't go away.
Has anyone come across this before?

The code could be related to the spate of low voltage conditions and could possibly be reset now that the battery has more charge - not sure though. I know you've reset it before and it's returned so perhaps removing power from the whole car (disconnect negative battery lead for 10 mins.), then repowering (with battery in good condition) will allow all the MIL systems to complete their diags. properly.

These cars are VERY fussy when the voltages fluctuate - and my BMW motorcycle is the same. Must be a BMW design feature...

[evertonfc]

I would try anything at this point haha

[oldskewel]

Here's a suggestion to consider, not related to the CEL ...

I once had a battery on a different car (old Porsche) that would cause the same behavior = no start, seems almost dead, but not completely, then as soon as I'd apply jumper cables to a good battery it would fire up perfectly, as if the battery were 100%.

I spent almost a year checking every connection, ground strap, etc., and this intermittent problem remained.

Then I swapped batteries and the problem never came back. I concluded there was an internal circuit fault within the battery. It was a fairly new Optima Red Top, which was then replaced on warranty. Since it was intermittent, it was lucky that I got the warranty exchange on it.

[evertonfc]

The car had problems with keeping a charge from the minute i bought it.
The dealer I bought it from fitted a "new" (older than me as it turned out) battery that fixed the problem for a the summer but by winter the problem was back. So I bought a new one. that worked for a while but then the problem returned. I took the battery back to the store who checked the battery and the charging system and said they were fine so they wouldn't exchange it. that winter I bought a portable booster and I've relied on that for the last two years. Even if I drive 200 miles on the highway there is no guarantee (especially in winter) that it will start in the morning.
It's a strange one for sure.

[wpoll]

Originally Posted by evertonfc

The car had problems with keeping a charge from the minute i bought it.
The dealer I bought it from fitted a "new" (older than me as it turned out) battery that fixed the problem for a the summer but by winter the problem was back. So I bought a new one. that worked for a while but then the problem returned. I took the battery back to the store who checked the battery and the charging system and said they were fine so they wouldn't exchange it. that winter I bought a portable booster and I've relied on that for the last two years. Even if I drive 200 miles on the highway there is no guarantee (especially in winter) that it will start in the morning.
It's a strange one for sure.

This is really starting to sound like a parasitic drain issue. There's a few threads about battery drain on this and other forums - have a look. I'll see if I can find a really good step-by-step that someone here did once too.

Handy with a multi-meter?