[turbonium]

My car's entire DME/electrical axis has freaked out, trying to figure out what the hell happened...

Background:
'07 e90 335i sedan, manual trans, 150K. Battery replaced & registered Dec 2013. I believe the [electronic] water pump was also done recently, not 100% sure. I replaced a bad crank angle sensor in Feb and a broken rear window regulator Saturday. Driving fine until:

Symptoms:
Parking on a hill, I accidentally stalled by popping the clutch in gear while holding brake pedal. I remote-locked & left it for 3h (w/o hitting the stop button). Came back to a dead battery--wipers and interior lights had been going haywire the whole time. After using physical key & a jump from AAA, it drove fine for 40 mi before going nuts again.

With a recharged battery (trickled at 2A/12V overnight), external CA locking/unlocking works & engine starts promptly, but with these symptoms:

• DSC warning
• DBC warning
• ABS light
• start-off assist inactive warning
• airbag light
• yellow battery light [NEW AFTER TRICKLE-CHARGING]
• auto wipers start going & won't shut off
• power windows won't lower/door lock & DTC console buttons inactive
• dash & interior lights randomly flicker (drained battery only)
• iDrive/nav screen goes blank, comes on only erratically.
• yellow and red temp/overheat warnings come on in quick succession while driving (when warm, haven't tried cold)
• on temp warnings, first get limp mode power (yel), then no power at all (red), tho the engine doesn't stall & temp gage stays in normal position.
• HVAC system won't blow hot air when engine warm.

Engine Bay:

• Minor coolant seepage (~50mL) @expansion tank gasket--doubt it's related.
• Serpentine belt intact, alternator pulley running.
• Radiator fan not running @idle when temp warning displayed.

Not convinced it's really overheating, unless faulty DME is failing to run the water pump(?)

No way to pull codes and can't see verbose iDrive messages. But I hope this rings a bell for someone. I first suspected the AAA jump start, but now believe it was this electrical freakout cycle that killed the battery in the first place while parked...so what caused it? :dunno:Battery obviously starts the car (repeatedly), but could it be faulty in some other way? Did I trigger some ABS/DBC module weirdness when I stalled it? Thoughts much appreciated!

 

[turbonium]

This was TL;DR when I posted yesterday, I've simplified now, hope it's easier to wade thru.

 

[fdriller9]

Have you had the battery cable recall done?

Sounds like a loose battery connection issue.

 

[turbonium]

Battery cable recall was done. Terminal clamps are tight; I made sure of that after charging.

 

[CALWATERBOY DUE]

.

Dude, it's high time to do some trouble-shooting --- [view & do]

How'd it go? And let's not forget: Frequent trips <10 mi result in net battery drain.

 

[fdriller9]

Try disconnecting the IBS sensor BSD line off the negative terminal. See if the issues persist.

 

[turbonium]

Due to my regular indy being on vacation and a booking snafu with the other local euro shop, I kinda skipped to the end of your troubleshooting tree. Car was stone dead this morning after I'd charged it 15h Sun PM and driven it a grand total of of 100 yards. So now I assume bad battery or short circuit. Pulled the battery (61212353810) and lugged it to O'Reilly where:

 

[turbonium]

I thought 2.5 years wasn't much to get out of an oem bosch battery, but I do make a lot of short trips so CWB's comment about net drain is on point. Replaced with a Super Start 49EXT...group 49, H8, non-AGM. (hope that's the correct one, as the liquid freely sloshing in the old battery seemed to indicate it wasn't the AGM type.) It drives around the block with no codes or craziness, will have to see if that holds up on a longer excursion.

I gather I need to register the new battery and clear the DME fault codes...no cheap way to DIY this, I'm guessing. Unless someone local to Menlo Park CA has a scan tool and laptop and feels keen...

 

[fdriller9]

Due to my regular indy being on vacation and a booking snafu with the other local euro shop, I kinda skipped to the end of your troubleshooting tree. Car was stone dead this morning after I'd charged it 15h Sun PM and driven it a grand total of of 100 yards. So now I assume bad battery or short circuit. Pulled the battery (61212353810) and lugged it to O'Reilly where:

A discharged battery will ALWAYS test bad.

A load/battery test is suppose to be done a fully charged battery.

 

[turbonium]

Hmm. This AutoMeter XTC-160 tester follows a set program. It accepted the dead battery and indicated it would first charge it prior to testing. It promised to give an estimate of total charging time after 10min. After the 10min had elapsed, it said another 10min would be required. After that period, it displayed the messages shown (bad battery, bad cell, thumbs-down light) and automatically aborted the charging cycle.

Are you saying these commercial charger/load-testers can be inaccurate in diagnosing a bad cell? After I trickle-charged it all night, I also got a yellow battery symbol added to my cluster of dash warnings, so my DME also thought there was something wrong with the fully-charged battery.

Maybe I've made an unwise choice, although given typical shop rates the battery seemed the cheapest thing to try! It's installed and I exchanged the core, so I can't go back. I should probably try to check for a parasitic draw, but I don't have an ammeter DVOM on hand.

ETA: Just drove to local shop, where I had intended to register battery and clear codes. No faults or weird behavior on the way there, but they found the battery is not charging under load, and the DME will not even communicate with their [factory] diagnostic scanner. Now wondering if the alternator flaked out and took some fuse(s) or module(s) down with it.

 

[CALWATERBOY DUE]

.

OK couple o'things:

Overly discharged battery may be sulfated....scan up a bit from the end of my troubleshooting link to see about desulfating.

Also score a desulfating charger per link. Many short trips are an issue - CTEK's the cure.

Now then. Could be you have a parasitic drain - view the video on that; check it out.​

Better?



.

 

[turbonium]

I''ve already replaced the battery, so can't do the desulfating this time, but will look into CTEK charger. New battery fixed the visible symptoms--no warning lights. But the shop couldn't register the battery because their tool wouldn't talk to the DME. (They later found their connector was missing a pin needed only for a few model years, including mine.) While diagnosing this, they found the idle voltage at just 12V. No parasitic draws evident. Swapped out alternator (Bosch re-man) and all is well.

Looking back, the first symptom was erratic behavior from CA key--I'd get out and the car would spontaneously lock, or the locking mech would trigger on and off rapidly. Then the DSC or ABS light alone. With new alternator we're at >14V, idle and accel noticeably smoother.

 

[wilt]

I gather I need to register the new battery and clear the DME fault codes...no cheap way to DIY this, I'm guessing. Unless someone local to Menlo Park CA has a scan tool and laptop and feels keen... the shop couldn't register the battery because their tool wouldn't talk to the DME.

Send me private message with your phone number / email address, and I can contact you regarding using Carly to register your battery...I am in Belmont, about 8 miles to your north.

[edit] I am uncertain if I can do battery coding with my Bluetooth BMWhat adapter on your 2007...it would not properly link with someone's 2007 when he had me try to code it early this year. What is your production date?