[GrimTheDragonLord]

Hey y'all I'm back with my problematic E91.

For those new, Hey! I'm Grim, I own a 2007 BMW 328xi E91 (06/07). Last time we took a dive into the many issues of it but I've come up with more that I want second opinions on and extra knowledge about. (Shoutout to those of you who have helped me, and to that one person yes I finally got my oil filter housing replaced as well as the power steering pump, not the wiring or the tpms sensor tho )



Today at a stop light after accelerating a little rough my car suddenly jerked and threw an abs light for a split second before showing the dreaded limp mode icon (the half filled in check engine light if it is that). Car seems to run fine for the most part, looked into limp mode specifically but she seems to be fine going a little past 40, I have no been driving past 50mph just in case so I dont know what exactly what my limp mode limit is. Did do some code readings so I will post all those here...




Im not worried about the airbag codes since I currently have my passenger seat out. If anyone knows about something for the wiring or how I can basically stop my BMW from screaming at me about the seat id love to know.

And to aid my lovely nerds on what this current problem could be I have a 12v line running from one of my front connectors to something, after my little incident the piece I have connected DOES NOT WORK ANYMORE! I have looked into it but it says something about a power wire in my back wheel well with the battery. Which if that is the issue im hoping for an easy fix to get her up and running again.





I would love to be able to just WING shit and make things work, but all this research and second guessing brought me back here to ask. Whether I stay around again or not depends on if my damn car survives. Maybe one day you all will get to see her upgraded and looking pretty, but for now its one problem at a time. Thank you all for any support you give. <3

[TunafishE93]

[gbalthrop]

Originally Posted by GrimTheDragonLord

... 2007 BMW 328xi E91 (06/07)... Today at a stop light after accelerating a little rough my car suddenly jerked and threw an abs light for a split second before showing the dreaded limp mode icon... Car seems to run fine for the most part...
I have a 12v line running from one of my front connectors to something, after my little incident the piece I have connected DOES NOT WORK ANYMORE!... [DME Codes currently present: 2A77, 2A3F]

VVT is German abbreviation for "Valvetronic" (NOT Variable Valve Timing, which is VANOS ;-). Valvetronic is the system that controls Intake Valve Lift or amount the intake valve opens to admit air to the engine. In your case, you have NO power to the VVT portion of the DME via Fuse F07 in E-box, & VVT Relay, & hence, NO power to the VVT Actuator Motor that moves the Eccentric Shaft to change Intake Valve "Lift". So DME goes into "Limp Mode": your engine will start & run at "Minimal" throttle, with amount of air admitted to engine NOW controlled by the Throttle Valve.

Question #1 is: WHY are your getting NO/reduced voltage via the small, Red wire that runs from the RPDP (Rear Power Distribution Panel) on top of the battery, to the larger nut shown in your photo? Restore that voltage supply, & your VVT system should work. Question #2: Who installed the wire shown in your photo, what does it attach to, & did that wire/device short out your VVT voltage supply wire?

Tool needed: Multimeter, ~$10 at HFT or Amazon.

Steps:
1) Measure/Report Voltage at both large nut & small nut in your photo.
2) Disconnect the "Mod-wire" attached at small nut in your photo, to remove any chance of "Short".
3) Measure/Report Voltage at SMALL red B+ supply cable shown in photo attached to NEXT Post. That's the Cable in the lower-center of the photo, labelled "B+ to VVT Relay in E-box". You can simply disconnect the connector where the yellow paint is in the photo. We're testing for a BLOWN/melted fusible link at that connector.
4) The video is describing a different possible cause of low voltage: rusted "Transfer Point" where that small, red cable passes current THROUGH the RR Fender-well to the cable that runs forward to the Jumpstart Terminal. The test in (3) above will show if you have lost power BEFORE you even reach that Transfer Point.

Try those tests, report your results, & we can suggest "NEXT Steps".
George

[gbalthrop]

Attached is photo from my 3/2007 build 328xi, with Cables at battery & RRPD labelled, per prior post.
George

[GrimTheDragonLord]

Originally Posted by gbalthrop

Question #1 is: WHY are your getting NO/reduced voltage via the small, Red wire that runs from the RPDP (Rear Power Distribution Panel) on top of the battery, to the larger nut shown in your photo? Restore that voltage supply, & your VVT system should work.
Question #2: Who installed the wire shown in your photo, what does it attach to, & did that wire/device short out your VVT voltage supply wire?

George

To answer number 1 I believe its because I'm using a smaller battery, number 2 I did it myself, it runs to a PA system that draws 100w apparently. MOST definitely the cause if the problem now that I'm actually looking into it. I was told to run a fuse from my dad or move the line since we dont know how many watts/volts that line runs. If someone can suggest a better ground wire spot cause I have it ran into one of the bolts that holds the suspension.

I ordered a nice Multimeter off Amazon and have it coming in soon so I will be back to give y'all the info when I can.

[GrimTheDragonLord]

Do mind the mess, managed to find one of my wires is a little messed up so that sucks. I don't think its the DIRECT cause but it sucks to see, also as you can see my battery is not a full sized one you see in most bmw's.

[TunafishE93]

Check to see if you have any voltage on the wire that is open, if not then it plugs into a fuse right at the battery.

[gbalthrop]

Originally Posted by GrimTheDragonLord

To answer number 1 I believe its because I'm using a smaller battery, number 2 I did it myself, it runs to a PA system that draws 100w apparently. MOST definitely the cause if the problem now that I'm actually looking into it. I was told to run a fuse from my dad or move the line since we dont know how many watts/volts that line runs. If someone can suggest a better ground wire spot cause I have it ran into one of the bolts that holds the suspension...

Originally Posted by GrimTheDragonLord

... managed to find one of my wires is a little messed up... as you can see my battery is not a full sized one you see in most bmw's...

I was young once & thought I knew it all. Lesson #1: Listen to Dad.
Your B+ Cable from X1984 that supplies F07, the VVT Relay, & your VVT Actuator appears to have badly-melted insulation from your photo. The ground wire you installed probably looks equally melted, or else you have quite a short-to-ground elsewhere.

Your fusible link -- the meltable metal link that carries power to the connector (X1984) at the rear of the RPDP, for the Cable you are holding in your left hand, is probably melted. That can be quickly tested with a Multimeter, or even a light bulb/ Test Light. Melted/Cut/Damaged insulation can be wrapped in electrical tape, at least for quick test purposes after you fix the melted link. That link, F102 is rated at 100 Amps & if your Amp is drawing a max of 100W, that is about 8 amps on a 12V system.

Unfortunately, I'm NOT aware of any source for the link alone, & the entire RPDP is ~ $100. So make sure you found the source of the short BEFORE replacing the Rear Power Distribution Panel.
https://www.ecstuning.com/BMW-E91-32...h/61146971370/

As for batteries in Marietta, GA, size should NOT matter. A smaller battery does NOT produce less voltage. It just has lower "Cranking Amps", which are not as important in warmer climates. Your battery compartment, & "Tie-down bracket" at rear of battery, are designed to fit an H6, H7 or H8 size battery case. (See my previous photo). There SHOULD be a long bolt at the rear of the battery, holding a bracket that secures/wedges the rear of the battery to keep it from sliding about in the battery well. There is a "Clamp" also a front of battery.

What IS important, is the "Setting" in the CAS Module, for Battery (A) TYPE (AGM vs. FLA) & (B) Capacity (Amp-hours). While a battery of any type or capacity will work in your vehicle, WITHOUT any coding of the CAS Module, it will NOT last as long, as the charging profile will NOT be correct. Simply "Registering" a new battery will NOT change how it is charged.

There are a LOT of folks, on the forums & in shops, that are GOOD Mechanics. Unfortunately, they have avoided learning about "Electrickity", 'cuz they can't see it, & it's a scrary, unknown quantity. So please take the time to analyze, read, ask questions, ask Dad, etc. ISTA ScreenPrints are attached to NEXT Post.
You can do this,
George

[gbalthrop]

Attached are ISTA ScreenPrints related to prior post.
George

[TunafishE93]

You can just use another empty plug if your fuse is blown. I believe they are all fused.

[GrimTheDragonLord]

Originally Posted by gbalthrop

Lesson #1: Listen to Dad.
George

I shoulda listened, he runs a PREFAB shop and has recently started doing Tech work on the field...

Originally Posted by gbalthrop

What IS important, is the "Setting" in the CAS Module, for Battery (A) TYPE (AGM vs. FLA) & (B) Capacity (Amp-hours). While a battery of any type or capacity will work in your vehicle, WITHOUT any coding of the CAS Module, it will NOT last as long, as the charging profile will NOT be correct. Simply "Registering" a new battery will NOT change how it is charged.

George

I had actually known about BMW's needing a proper battery read when I first got the car since we had to buy a whole new one. I still have the old BMW battery lying around somewhere. Guess it finally caught up to me or my PA just decided to blow shit up. I got a personal multimeter ordered but I may be able to get one earlier if I check my dads shop, might be able to get some new wiring off him. Ill try to catch up on my reading as well cause its currently 2am and I'm scratching my head looking at all this.

[gbalthrop]

Originally Posted by GrimTheDragonLord

... I'm scratching my head looking at all this.

To make it easier & simpler:
1) Don't worry about the Battery for now; just remember we need to talk about that AFTER you get the VVT power supply sorted;

2) Disconnect that small Red B+ cable (one with damaged insulation shown in your photo), & test for voltage at its connection (X1984) at rear of Rear Power Distribution Panel. You can use ANY Multimeter, or even a "Test Light" -- if the bulb doesn't light, you have a melted "Link".

3) As Tunafish suggests, there are other links you can plug into (if cable will reach) or test for voltage at rear of RPDP. You can also test your Light or Testing technique at the battery terminals, the Jumpstart Terminals under hood, or even a small battery, AA, AAA, 9V, etc.

4) To get your car's power restored, you need to get power from the Battery (+) Terminal to the Small Red Cable, AFTER you fix the Insulation on that cable.

5) To assess/fix the issue correctly, you should probably remove the battery, remove the Small, Red cable with damaged insulation, inspect the Transfer Points (open the black plastic covers), & either carefully wrap that damaged cable with electrical tape, or replace it.

6) Please ask for help BEFORE you remove the battery, as there are some details that are hidden, such as the wiring on the BST (Battery Safety Terminal) at the (+) Battery Terminal, the Vent Tube, the IBS (Intelligent Battery Sensor) wiring, etc. NONE of that is complicated; just a Number of Details -- you need photos & a checklist. Good time to learn how it all works.

Just new concepts. You can handle them.
George

[GrimTheDragonLord]

Got around to doing tests. Disconnecting the Small Red B+ Cable and reading it gave me 4v. I checked the my terminal at the front as well with the big nut giving me a fluctuation between 1-7v and the small nut, the one that has my PA system connected on at 0v. This test was done with the car off and my multimeter set to 20v DC.

[GrimTheDragonLord]

Update : I wrapped the cord up and I'm still getting 4v out of it. When plugged into its original spot and testing the two terminals in the front of the car my small nut (with PA), is fluctuating between 1-3v while the big terminal gets around 12v.

[gbalthrop]

Originally Posted by GrimTheDragonLord

Update : I wrapped the cord up and I'm still getting 4v out of it. When plugged into its original spot and testing the two terminals in the front of the car my small nut (with PA), is fluctuating between 1-3v while the big terminal gets around 12v.

If you only have ~ 4 Volts at the X1984 socket with the X1984 Connector removed, so the Small Red Cable is no longer connected, you have found your problem. The fuse area (see black area of each "prong" or fusible link in the attached photo, from 'E90 Voltage Supply' BMW Training Manual) has partially/mostly melted resulting in limited electrical supply at that "prong. Note in the photo that there are 5 smaller prongs, & X1984 is connected to the 1st smaller prong from the left, next to the Medium-sized Red B+ Cable that runs inside the car to the JB Fuse Box. You should test voltage at the 2nd & 3rd prongs. IBS (Intelligent Battery Sensor) gets its "Reference" battery voltage via the 3rd prong.

The Fusible Link has 6 Prongs, including the Larger Prong to which the Medium B+ Cable is attached with Nut. Each of those is connected to the Battery B+ Terminal by that same Link. The Link is NOT separately available, so you would have to buy an entire new RPDP if you can't connect to a functioning "Prong" with 12V+ battery voltage.

If you use a bright light, shining into each opening on the rear of the RPDP, you should see a metal prong inside each. Test the two prongs outboard of X1984 prong, to see if BOTH are same as Battery Voltage. You can measure battery voltage between the two battery posts to see if it has 12.0V or more charge.

If you have wrapped ALL damaged portions of the Small Red B+ Cable in Electrical Tape, you can connect that to the 2nd 'Prong' of fusible link (as long as you have disconnected the PA or whatever was "Optional Extra" added at the firewall.. Test at nut at firewall to make sure you now have battery voltage there. If so try starting engine & see if VVT now functions as it should, Clear two DME fault codes, & let us know how it went.

Questions:

1) What are you referring to as the "big terminal'? The B+ Jumpstart Terminal under the Red Plastic cover should be battery voltage. That terminal is supplied by the LARGE Red Cable from the Battery Positive Terminal via the BST (Battery Safety terminal.

2) Have you DIS-connected any PA or other aftermarket device attached to nut at firewall? Do that BEFORE connecting Small Red B+ cable to RPDP at battery.

3) IF there is still NOT 12V+ (battery voltage) at the nut at firewall after the steps above, please attach photo or description of WHERE Voltage is measured, in Each Case.
George

[GrimTheDragonLord]

Ahhh I was measuring the X1984 wire itself not the fuse link. Tried once more today, connector read 4v, the fusible link the X1984 wire WAS connected to was running 0v with the fuse next to it running 12v. I tried testing the other fuses but they all said 0 so idk if im testing that correctly. All of this was with my multimeter ground set to the battery's ground.

1. The big terminal was just the big nut that powers the starter
2. I disconnected the PA today and set the wire to the side, that was the only thing I had connected.
3. Once more I tested all the prongs and only got one which was reading 12v which I cant connect to because of the connector shape.

Am I just being slow or...