[Raul1234]

Hi all,

I'm new here so hope I'm posting this in the right place.

I have a 335d e92 LCI and the car is driving me crazy at the moment. I own the car for the past 3 years and when I initially bought the car it had a battery issue that I didn't know about until I started doing 10 minutes journeys then park the car for 2 hrs then another 10 minute journey then park the car again then after the car wouldn't start and it got narrowed down to a bad battery which I replace and it was fine until 6 months ago. That is when my nightmare started.

Now the car is draining the battery even if I drive the car all day the next morning it starts but just barely and I get the "Increased Battery Discharge" message on the idrive. If it stays parked for 2 days or more the battery is flat and I need to jump start it in order to drive it. The battery has been replaced again when the issue started and the alternator is good charges the battery how it should.

A parasitic draw test was conducted and it seems that once it goes to sleep the drain is 10mA which to my understanding is that that is okay but the issue is that something wakes the car up and the drain jumps to nearly 3A and stays there for few minutes then it drops down to 100mA for few minutes then back down to 10mA for few minutes then the cycle starts again going to 3A and back down and so on. Every time the car wakes up you can hear a buzzing noise from under the bonnet I might be wrong but it sounds like something it tells the injectors to get ready as the car is about to start.

The car was in with BMW which said that is the CAS module which I replaced then I went back to them with the drain issue and said they can't get to my problem as my car is modified and their equipment can't read anything despite the fact that first time it did I try argue my case but it was not wining with them so I just left it at that. Also the modifications I have did not do this as the car had the issues well after my modifications also the mods are mechanical such turbos, intercooler, high pressure fuel pump and exhaust.

All the modules have been unplugged and there was not difference noticed and the same with the fuses. I have to mention that the diagnostic equipment says I have about 52 faults on the K-CAN.

Has anyone experienced anything like that or can point me in the right direction as to what to look at next as I'm stuck and no idea what to approach next?

Thank you all in advance.

[TunafishE93]

I assume the alternator been tested since that would be where shops works start?

[Raul1234]

Originally Posted by TunafishE93

I assume the alternator been tested since that would be where shops works start?

Yes alternator has been tested and battery and alternator are fine from all points of view.

[gbalthrop]

Originally Posted by Raul1234

Yes alternator has been tested and battery and alternator are fine from all points of view.

Tested HOW & BY WHOM, with WHAT TOOL? Not to be a wise-ass, but your description has all the earmarks of an intermittent Alternator Diode Fault. The Alternator Diodes act as "Check Valves" to prevent current flow from Battery, back to Alternator when engine is OFF. They are the FIRST suspect for what you describe.

The linked METERK Mk06 for 29 Quid, will allow you to monitor the current draw, or Parasitic Battery Drain, simply by clamping a wire (if the drain is in the 3A range you suggest). Really, anything ~ 200 mA or more (0.2 Amp). Make sure you get a Clamp meter that can measure BOTH AC and DC AMPS/Current. I have the MeterK Mk06 and it WILL do this job. Here is a link to Amazon UK source:
https://www.amazon.co.uk/Meterk-Mult...1802533&sr=8-8

As with any intermittent fault, you have to "catch it in the act." There are THREE (3) B+ or Battery Power Supply cables (Large, Medium & Small diameter) going from the Rear Power Distribution Panel over the battery to various Consumers:
1) The Large Cable goes Down to a Transfer Point forward of the battery base, and then forward beneath the vehicle to the Jumpstart Terminal, Alternator & Starter Motor;
2) The Medium Cable runs Upward & INSIDE the vehicle to the JB Fuse Panel;
3) The Small Cable (at least on gasoline-engined models with DME as opposed to DDE) runs Down to Inboard Transfer point and beneath vehicle to E-box where DME is housed.

I would suggest getting that meter and doing your own diagnostics. I would START by identifying WHICH of the B+ wires (three on gas-engined E9x models) is carrying the excessive Quiescent current. If it is the LARGE B+ Cable, it is almost certainly the Alternator. In fact I would leave the bonnet open, close boot & doors, lock the vehicle, and allow it to enter Sleep Mode. THEN put clamp meter on large B+ cable to Alternator, and "baby-sit" it for Current Flow.

If it turns out to be one of the other B+ Cables, post back with the Last-7 characters of your VIN and we can provide specific fuse/circuit information.

BTW, I hope "BMW" Re-connected your Modules correctly, AND Re-installed your fuses correctly. Somewhat "Daft" I would say.

If you would like to get INPA and/or ISTA downloads (Free) and do your OWN diagnostics "going forward" (HATE that "trendy" phrase ;-), let us know and we can provide links & info.
George

[Raul1234]

Originally Posted by gbalthrop

Tested HOW & BY WHOM, with WHAT TOOL? Not to be a wise-ass, but your description has all the earmarks of an intermittent Alternator Diode Fault. The Alternator Diodes act as "Check Valves" to prevent current flow from Battery, back to Alternator when engine is OFF. They are the FIRST suspect for what you describe.

The linked METERK Mk06 for 29 Quid, will allow you to monitor the current draw, or Parasitic Battery Drain, simply by clamping a wire (if the drain is in the 3A range you suggest). Really, anything ~ 200 mA or more (0.2 Amp). Make sure you get a Clamp meter that can measure BOTH AC and DC AMPS/Current. I have the MeterK Mk06 and it WILL do this job. Here is a link to Amazon UK source:
https://www.amazon.co.uk/Meterk-Mult...1802533&sr=8-8

As with any intermittent fault, you have to "catch it in the act." There are THREE (3) B+ or Battery Power Supply cables (Large, Medium & Small diameter) going from the Rear Power Distribution Panel over the battery to various Consumers:
1) The Large Cable goes Down to a Transfer Point forward of the battery base, and then forward beneath the vehicle to the Jumpstart Terminal, Alternator & Starter Motor;
2) The Medium Cable runs Upward & INSIDE the vehicle to the JB Fuse Panel;
3) The Small Cable (at least on gasoline-engined models with DME as opposed to DDE) runs Down to Inboard Transfer point and beneath vehicle to E-box where DME is housed.

I would suggest getting that meter and doing your own diagnostics. I would START by identifying WHICH of the B+ wires (three on gas-engined E9x models) is carrying the excessive Quiescent current. If it is the LARGE B+ Cable, it is almost certainly the Alternator. In fact I would leave the bonnet open, close boot & doors, lock the vehicle, and allow it to enter Sleep Mode. THEN put clamp meter on large B+ cable to Alternator, and "baby-sit" it for Current Flow.

If it turns out to be one of the other B+ Cables, post back with the Last-7 characters of your VIN and we can provide specific fuse/circuit information.

BTW, I hope "BMW" Re-connected your Modules correctly, AND Re-installed your fuses correctly. Somewhat "Daft" I would say.

If you would like to get INPA and/or ISTA downloads (Free) and do your OWN diagnostics "going forward" (HATE that "trendy" phrase ;-), let us know and we can provide links & info.
George

The alternator was checked by the 2 mechanics I had my car down at and BMW. I would love to know more information about how they done it and what tool they used but I do not have that information.

I appreciate your guidance I will order the meter you have suggested and once it arrives I will go to the garage where I currently have the car and do this test will post again on the findings.

The fuses and modules are correctly re-connected they have been double checked by the mechanics one of them done it in my presence as we are friends.

I have INPA downloaded from the bimmergeeks website I do not have ISTA so if you would have the link for it I would appreciate if you can send it to me. I didn't use INPA yet to try do my own diagnostics as I am trying to source a laptop first as they are currently on my computer and is going to be hard to bring this down to the car haha

Thank you for the advise George!

[gbalthrop]

Originally Posted by Raul1234

... I have INPA downloaded from the bimmergeeks website I do not have ISTA so if you would have the link for it I would appreciate if you can send it to me. I didn't use INPA yet to try do my own diagnostics...

Attached are two pdf's:
1) E9x References which contains information & Links on such things as Bentley Manual, INPA (BMW Standard Tools & E89 Datens), and ISTA/ Rheingold.

2) INPA Tutorial Quickstart which describes HOW to Setup & Use INPA, just to get started. It shows some example Screens, and summarizes OTHER things you can do with INPA to get a LOT of Diagnostic Data, such as Fault Details, Freeze Frame Data, Live Data and Activations.

If you have the desire to learn that diagnostic system, best to ask a lot of questions and post ScreenPrints on the Forums to get advice/translation, as trying to figure it out all by yourself is difficult, particularly for NON-German-speaking Folks.

George

[Raul1234]

Originally Posted by gbalthrop

Attached are two pdf's:
1) E9x References which contains information & Links on such things as Bentley Manual, INPA (BMW Standard Tools & E89 Datens), and ISTA/ Rheingold.

2) INPA Tutorial Quickstart which describes HOW to Setup & Use INPA, just to get started. It shows some example Screens, and summarizes OTHER things you can do with INPA to get a LOT of Diagnostic Data, such as Fault Details, Freeze Frame Data, Live Data and Activations.

If you have the desire to learn that diagnostic system, best to ask a lot of questions and post ScreenPrints on the Forums to get advice/translation, as trying to figure it out all by yourself is difficult, particularly for NON-German-speaking Folks.

George

Thank you for the PDFs I will download the software order the cable and look for a laptop to use only for diagnostics and stuff like that.

I've also got the clamp and managed to check the cables and the alternator for faulty diodes unfortunately no help everything was fine on all the tests.

Now I'm back where I was but with one more thing tested and still no result the battery is still getting drained, if there is anything you can think that might help please let me know I have no idea what to look at next.

[JonnoVision]

Hi - how did you get on with this? I have the same issue on my 2009 E90 320d MSport