Battery or Alternator shot on an '06 E53 4.4i X5?

[sagdast]

I have an '06 E53 X5 4.4i that I drive every few weeks. This week it started up fine, but after 5 minutes of driving, I noticed the engine start shaking at idle, the 4x4 light come on, the yellow brake warning light come on and the matrix announce "Trans failsafe Prog." Navigation system would go in and out, doors and trunk wouldn't unlock, and the transmission would go into reverse with a kick. This car has 91k miles and has been babied. Is this just a bad alternator wrecking havoc on the electronics or something much worse? I would rather take it to a local indie shop and tell them to replace the battery/alternator vs. be at the mercy of a stealership. I swiftly drove home, turned it off, and tried turning it back on. It struggled to start, MUCH harder than it did the first time after sitting for 3 weeks, and when it did, everything was back to normal, and the reverse kick was gone. Is this an alternator problem?

[TheAngryBear]

Effectively went through this myself.
Likely the alternator.
Best way to tell is pull the codes and the causes by INPA or equivalent.
My codes showed hi/low voltages not currently present. Then I watched the voltage via cluster test 9 confirming spikes.
Likely could have just gone regulator but same amount of work and the regulator comes with the alternator.
Since replacement, all has been well.


2001 750iL DD74441
E65 fan & clutch, E65 headrests, Front First Aid Kit, Ultimate Cup holder

2005 X5 4.8is LE82680
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[sagdast]

Wow TheAngryBear thank you so much this is excellent. Mechanic quoted me about $450 for the alternator and $350 for labor. I'm trying to avoid a tow truck - if I rev the car at intersections can I assume that there is something going back to the battery or should I just assume NOTHING is going back to the battery and should just tow? Trying to save what's likely to be another $100+ for a tow.

[sagdast]

Also is there a code scanner you would recommend?

[TheAngryBear]

So you have voltage going back to the battery. The risks of driving like this include:
-those systems are non-operational
-voltage spike fries a system/module
-battery dies and stranded

So you MIGHT get out of a tow but could risk a module being fried. You will need to weigh the risk benefit. I did my own change of alternator so pricing is much more than I paid. We are also off by a year or two so maybe alternator changed as well.

As for scanner, I recommend INPA/EDIABAS. You can go a few routes based on your funds and systems:
-buy the cable and download a free version and install yourself (May have to source an appropriate computer)
-buy the cable and software package (May have to source an appropriate computer)
-buy a full package

Everyone has their favorite source, google is your friend here based on your funds and system(s).


2001 750iL DD74441
E65 fan & clutch, E65 headrests, Front First Aid Kit, Ultimate Cup holder

2005 X5 4.8is LE82680
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[Qsilver7]

If you unlock your instrument cluster...you can run TEST 9 and watch your charging system's output as you're driving along. Or if you don't start the vehicle and only turn to KL R (ignition position 1) you can see what your battery voltage is.

If you've never heard of unlocking your cluster to access the hidden tests...there are videos and instructions all over the internet and youtube. There's so many, you'll trip over them doing a search. You'll need to add up the sum of the LAST 5 digits of your VIN...that is the "special integer" that will specifically unlock your instrument cluster.

[sagdast]

Huge thank you @QSilver and @TheAngryBear!!!

[jclausen]

You could just take to the shop and have them test the charging system if you want a quick answer or you can dick around with it if you have another driver

[sagdast]

OK so I replaced the alternator and that solved the problem. HOWEVER, running Test 9 in the matrix when the cars is on shows 13.8 volts, BUT when the car is off, it starts at 12.4 volts and drops to 11.5 volts as the car sits with the navigation/interior lights on. Is my battery shot?

[TheAngryBear]

It could just need a recharge by a dedicated charger; NOT by driving around.

I’d say take it to autozone, pep boys, or equivalent for a free battery evaluation... but you are in CA. Don’t think they do that for free there. Maybe they do? CA has weird rules.


2001 750iL DD74441
E65 fan & clutch, E65 headrests, Front First Aid Kit, Ultimate Cup holder

2005 X5 4.8is LE82680
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[Qsilver7]

OK so I replaced the alternator and that solved the problem. HOWEVER, running Test 9 in the matrix when the cars is on shows 13.8 volts, BUT when the car is off, it starts at 12.4 volts and drops to 11.5 volts as the car sits with the navigation/interior lights on. Is my battery shot?

With the ignition in position 1 or 2 (KL R or KL 15)...and you're running TEST 9...the battery voltage will drop because multiple control modules are powered up...they are drawing power from the battery. Since the engine is NOT running, the battery is the only source of power so a drop in voltage should be expected.

The scenario in your quote above doesn't appear to be a problem. Your 12 volt battery is starting with a voltage above 12 volts when you start TEST 9...then drops as control modules power up (which is to be expected). If you were to use a multi-meter where you could check the battery without a large power draw...you should "hopefully" not see the same drop in voltage. The only thing powered up at first would be the things on the P-bus which powers up when the vehicle WAKES up (aka if you were to raise the unlock the vehicle or raise the tailgate or open the door & raise the hood). After 16 minutes (without any other wake-up calls on the P-bus)...the car will go back to SLEEP.