2006 525i: Help! Car won’t start, warning lights going crazy, struggles

[persiandude]

Car: 2006 525i
I was experiencing a really rough idle, loss of power at low rpm, lag during acceleration and then my Service Engine Soon light came on.

Used an Elm OBDII reader and got a code for a misfire in 5th cylinder. I replaced the coil pack with a new one and then started the car. Initially the car struggled to start and the rough idle was still there. I turned it off and started it again right after and it started up with no issues and the idle was better. I let it run for a minute or two then turned it off.

Few minutes later I went to try and clear the SES light and it wasn’t connecting to the Elm reader so I tried to start it and the car would start. Just several clicks and it seemed like it was trying really hard to start but didn’t have enough juice then it finally did. All the gauge lights and warning lights came on

• Brake stability
• Steering
• Transmission
• Lights I have never seen before

Turned it off and tried to restart and then it wouldn’t start, just struggled but never actually started. All lights were on the dash and iDrive gave every warning possible

Two days later its still having the same issue.

I connected a battery charger to the front + terminal in the engine bay and a bolt for the - terminal. The battery charger says its fully charged. I pressed the alternator button on the charger and got an indication there was something wrong with the alternator.

Recent work that has been done

• new tensioners
• new belt
• new starter
• oil cooler gasket

Is this just simply a bad alternator? Should I check anything else before changing the alternator?

Thanks!

[MIKYZZ4]

For accurate charging, and to prevent damage to vehicle computers,
I uninstall-charge to 100%of charge-reinstall.
Your symptoms had me suspecting a failing battery, but indications are that it is charged.
So we focus on the components down the line, like inspecting battery cables, engine -grounds,
for clean, snug connections. I notice you mentioned hooking up the charger to locations in the engine bay,
But no mention of the condition of battery connections at the actual battery posts.
Remove-inspect-clean-tighten, both battery connections. Check voltage across battery posts(12.4-12.7)at 100% of charge.
Start engine, check voltages at(idle-2000-3000rpm). Should vary between 13.5~14.5v. If so, your alternator is fine.

[persiandude]

thanks for the detail... I will check that out this evening and report back

[persiandude]

I have the battery out of the car and on the charger.

Black & Decker BC15BD 0-15amp automatic charger
Display shows:
40% full and charging @ 15.5 A
IMG_0122.jpg

Voltage Reading: 13.2 V

Are these numbers ok? Don't know much about electrical stuff or batteries

[MIKYZZ4]

If there is a slower charging rate, select that,
If not, just charge until the meter reads at 100% full charge.
Once fully charged, disconnect from charger and take voltage reading,
with a voltmeter if available, then install battery back in vehicle.
Start engine, check voltages at(idle-2000-3000rpm). Should vary between 13.5~14.5v. If so, your alternator is fine.

[persiandude]

Charged it until it was in float mode and read 100%. Voltage looked within range. Put the battery back in the car and it started right up. Voltage reading with the car idling is 14.1-14.2

Thanks for your help

[MIKYZZ4]

Excellent readings, your alternator is working fine.

[gmak]

Try disconnecting the IBS and see if the problem goes away.

Also, it might be a parasitic battery drain. Mine was caused by the comfort access module in the rear RHS door. This is apparently a common enough issue in these cars; and, it seems to happen 'overnight' with no previous warning. To find which one was the issue, I operated the comfort access on all 4 doors and looked for the one that didn't respond as well.

[persiandude]

I think I'm having battery related issues again. Intermittent fault codes will appear on the iDrive.

- Transmission fault that showed up once and then went away
- Anti-trap window fault that has since gone away.
- RPM jump and dip on startup that went away for a month or so after changing a coil pack but has since returned (this hasn't gone away like the other faults)
- Restraint system faulty - not sure if I put the battery back in the wrong way or something like that
- AC will cut out for a half a second when slowing down or applying brakes initially at low speed This one has been more recent
- systems slightly lagging at startup occasionally - also been more recent

Anyone with similar symptoms? Does the battery have a manufacture date printed on it?

[MIKYZZ4]

There should be a date stamp,
either printed or branded onto the plastic shell.

[persiandude]

I drove quite a bit at night on Saturday night - about 150miles at highway speed with no stopping - AC, Radio, Lights, Fog Lights and a few accessories. All of a sudden I got an ABS light, Transmission Malfunction light, Active Steering light, etc... This happened about a mile from the gas station and I needed gas. I knew the car wouldn't start if I stopped to pump gas but I had to do it anyway.

Car didn't start. Called Roadside Assistance and they came and jumped the car and it started and seemed ok - he said the battery was completely dead.
The roadside guy took off immediately after and when I turned my headlights on all the same warnings came on and the car could barely go more than 40mph and wouldn't really shift gears. All systems were shutting down.

Next day I bought a new battery at Autozone Duralast Gold (H9) 95R-DLG and put it in the car. All lights, door locks etc... worked but car wouldn't crank or start. Just a single click and had to get it towed to my house. (couldn't find a date stamp on the old battery but I have never changed the battery and Im not sure if the PO ever changed it. Exide 61217591085 which looks to be OEM.)

I tried to jump start the car with the new battery but it would barely try to crank and never turned over. Seems like an alternator issue but I don't want to assume that is all it is. Does it sound like I need a new alternator? Is it the 185a version for N52 engine?

Car has a new starter (replaced about 4months ago)

[MIKYZZ4]

Remove battery and hook it up to a real charger>10~20amps,not a damn trickle!
Charge overnight, reinstall in the morning.New batteries do not come fully charged off the shelf!!
Purchase a multimeter to obtain voltage readings, if we need to diagnose for alternator failure.

[persiandude]

Pulled the new battery and charged it overnight using a 15a Black & Decker Battery Charger - here are the readings

Using a multimeter
Before charging: 12.30v
After: 13.21v (battery charger display 13.3v)
In the trunk/connected: 12.58v

Car still wouldn't start. I connected the charger to the + - in the engine bay to see if I could use the "engine start" feature but the charger behaved as if it wasn't connected to anything

Where to go from here?

[MIKYZZ4]

Install battery.
Take voltage reading at this terminal in engine compartment:http://www.realoem.com/bmw/photos/61146923945

[persiandude]

Tested it in the engine bay at the terminal with the key in and without.

The readings don't hold steady and climb up to 110v and start ticking down even going negative. It appeared to hold steady twice at 13.2v with the key in and doors closed (after the key had been in for about 5 mins at ignition position 2) but I couldn't get that to repeat again

Still reading steady in the trunk 12.57v

[MIKYZZ4]

That doesn't sound possible-110volts!!
Your meter may be damaged or a fuse has popped inside of it.

[persiandude]

That doesn't sound possible-110volts!!
Your meter may be damaged or a fuse has popped inside of it.

thats what i was thinking too so i went and tested it on the installed battery 4 times in a row and got the same exact reading, then i tested it on a 1.5v AA battery and it worked properly.

Inside the engine bay at the terminal the reading would climb to 110 then slowly countdown all the way to zero at a rate of approx 3v per minute, occasionally hovering around 13v

Tested with the key in the ignition and without the key in the ignition. I cleaned the tips of the multimeter too. I will try one more time when I get back home

[MIKYZZ4]

Clean that terminal too. Both +positive and -negative.
Also observe voltage readings whilst someone connects and disconnects battery terminals in the trunk.

[persiandude]

Cleaned the terminals in the front - Here's a vid to better illustrate what's going on

Still have to check the multimeter while someone disconnects the terminals in the back

[MIKYZZ4]

gmac in post#8 might have the answer, disconnect the -battery cable IBS connection.
View this video:https://www.youtube.com/watch?v=ta0a...0anFAeU2Q#t=41
and read the comments of others.

[persiandude]

I wasn't paying attention to the LCD read out. The multimeter #s in the engine bay were measured in mV, 132mV with IBS unplugged, so virtually no volatage to the front of the car.

Also just noticed the BST has been detonated - is it possible to reconnect? Has a black housing around it and I'm not sure I should take it off

[persiandude]

Reconnected the BST and obviously the car started. Still have the ABS control systems warning and airbag light.

I'm left with this set up until I get a new BST - can I secure that with electrical tape until I can tackle the BST splice?
IMG_1578.jpg

[MIKYZZ4]

You can secure at your own risk-remember, the safety that part provides is eliminated in an accident.
Replacement before driving vehicle is recommended by me, Part#: http://www.realoem.com/bmw/photos/61126929324

ABS warnings and light can be cleared with a proper diagnostic tool, After you replace the cable!

[persiandude]

Thanks for all your help

[MIKYZZ4]

I'm happy to help, and that the mystery was solved!