Well that was not fun . . .

I was stopped at a traffic light, Four Mile Post Road and 6500 Whitesburg Dr, Huntsville when it changed to green. I moderately pushed the accelerator; there was a 'clunk' and; no motion. Power cycling the car, same thing. I set the emergency flashers and shifted into "N". A slight grade let me turn into a parking lot and coast to a parking place. I put it in "P" and tried again and it cycled through a series of error messages, stayed in "P", and shut itself off. So I called BMW Connect.

It was 4:00 PM Friday afternoon and after an hour and a half, no luck getting a tow truck with the "skate", the small wheels that fit under the rear wheels so the car can be put on a flat bed tow truck and taken to the dealer. By now the sun was down and it was headed to freezing temperatures. So we agreed to start again Saturday morning.

Various error messages seen:

• Drivetrain: Stop carefully
  Pedestrian Warning - Malfunction. Consult service center.
  Vehicle battery charge low - Charge by driving for longer periods use external charger. Function requiring battery will be switched off.
  iRemote reported 6i2% traction battery SOC

I have a video of each display during the aborted starts but it will take a while to reduce them to small, downloadable, files. Here are what I saw on the displays:
http://hiwaay.net/~bzwilson/BMW/repair_041.mov

http://hiwaay.net/~bzwilson/BMW/repair_051.mov

Bob Wilson

All of my tools and meters were at home but the symptoms are consistent with a 12V battery failure. Can't be sure until tomorrow when I go back to the car and take a peek. I'll also put a Scangauge on and see if there are any error codes to read out. But the primary goal on Saturday will be finding a tow truck company that can safely take the car to the dealership.

Good thing we're weren't mid-way to Arizona when this happened. Stuff happens so we deal with it and move on.

Bob Wilson

If your stranding turns out to be due to a failed 12V battery, did you have any prior warnings?

I hope to avoid a bad 12V battery stranding me by monitoring a voltage gauge plugged into the accessory power port underneath the center of the dashboard where it's easily readable. If I start seeing the voltage below 12V, I'll start checking the 12V battery's health.

alohart said:

If your stranding turns out to be due to a failed 12V battery, did you have any prior warnings?

I hope to avoid a bad 12V battery stranding me by monitoring a voltage gauge plugged into the accessory power port underneath the center of the dashboard where it's easily readable. If I start seeing the voltage below 12V, I'll start checking the 12V battery's health.

Click to expand...

No prior warning. It was the cycling later that suggested a weak 12V system.

The real answer is to use my DVM to monitor the 12V battery in the morning when I try to start the car and get it shifted into "N". I'll take some wheel blocks for the front tires incase I succeed. Possible outcomes:

• 1) no change - continue to work on getting a qualified tow truck. The local dealer will be open so we can have a 'face-to-face'. I'll have my car and can scamper around town to the 'usual suspects.'
  
  2) jumping from good car to BMW works and car goes into "N" before winking out - YEA ordinary tow service will work. It become a BMW shop problem on Monday.
  
  3) jumping from good car to BMW works and the car appears to go into READY and move normally with regular battery voltages - AAAGGGGHHHH!!!!! intermittent. "Problem cleared while testing." I will try to reach the BMW dealer via back roads.

Hummm, perhaps wheel dollies instead of wheel skids to get the car on a flat-bed transport?

The DC-DC converter frequently, but not always turns on when I unlock the driver's door. It seems to do so when the 12V battery's voltage is on the low side. So you might measure the 12V voltage after opening the driver's door to see whether it's over 14V. If it is, the DC-DC converter is on and is charging your 12V battery, so there would be no need to jump your battery from a good battery. But if the 12V battery's voltage is too low, the DC-DC converter might not start.

bwilson4web said:

2) jumping from good car to BMW works

Click to expand...

A BMW tech warned me about jumping the 12V battery without first disconnecting the high-voltage system by opening the orange disconnect under the driver-side frunk cover near the front of the car. The disconnect lifts to disconnect and pushes down to reconnect. However, I don't know whether the car will enter Ready state without the high-voltage system connected, or if so, whether connecting the disconnect while the car is in the Ready state might cause a problem. I would probably attempt to charge the battery from the good battery for a while before disconnecting the jumper cables, reconnecting the disconnect, and then attempting to enter Ready state.

Good luck!

Thanks!

I'm headed to the car in about 15 min. Will let you' all know what we find.

Bob Wilson

Our 2015 i3 REx had its first oil/filter change after 5 months when CBS notice in dash said service was needed. 5,221 km on REx and 7,400 km on battery. Systems check found defective 12 volt battery which was replaced. No symptoms prior to replacement.

It appears from looking at the parts list on www.realoem.com that the original battery for the i3 was changed to a higher capacity one if warranty work was required. This might also be a function of what's available easily in the USA verses importing one from Germany, but it might also be that they've had problems on (some?) cars with parasitic losses(?), and a larger one ends up being more reliable?

Found the 12V dead when I arrived this morning suggests a controller failed and effectively put a heavy load on the 12V so normal functions soon failed. I can't call it a failed 12V as another part may have been the excessive load.

The Saturday morning crew was much more clued and actually scheduled the work and sending an SMS message with the ticket:

The Friday evening the BMW rep told me she couldn't find a tow truck with 'tire skates' which are large plastic pieces that under the tires, allowing the car to be pulled onto a flat-bed. In reality, all that was needed is a tow truck with a tire, lift gate. Since it was 4:00 PM, it would not have been seen by the techs in time to diagnose, much less, repair. Still, it did mean a second trip to the car Saturday morning.

So I called the tow company and let them know the 12V is dead and the rear wheels are locked and can not be unlocked because of the dead battery. He showed up 20 minutes later and quickly got the car up and on the way to the dealer:



After securing the rear tires, the tow truck operator used the seat belt to 'tie' the steering wheel.



Calling the tow company was important because it let them know the actual condition of the car. So they sent the truck with the wheel lift gate. Unfortunately the magnetic, rear light bar would not attach to our carbon fiber hood so the operator put it against the base of the windshield ... and during the tow it fell down (there is a $500 fine if the bar is not there.) I probably should have laid a sweater or something under it to keep it from falling below the windshield.

No technicians on the weekend so I left the key with a paper and the 7 digits of the VIN with a sales clerk. Since I had a tire check that showed 5 mm with one 6 mm and the right front tire alignment off, I'll have them do an alignment and won't worry if they also rotate them side-to-side.

I'll share what they find but it looks like 'a week at the spa' for our BMW i3-REx.

LATE THOUGHT: It is important to test every aspect of the car during the warranty. The recent addition of a 100A, 40kW, charger allowed testing the fast DC charger. Other than the row of 'programming buttons,' I don't think anything has not be tested. But there are two non-standard mods: (1) coding for 75% REx operation and (2) the 2" receiver hitch for my wife's wheel chair carrier. In theory, these pose a risk to the warranty. ... We'll see.

Bob Wilson

Here are what I saw on the displays:
http://hiwaay.net/~bzwilson/BMW/repair_041.mov

http://hiwaay.net/~bzwilson/BMW/repair_051.mov

Bob Wilson

Left rear motor mount bolt broke. Apparently there is a TIS on this with a lot of things to check and replace the motor mount.

When I mentioned left-right tire rotation, the tech and service writer had not heard of this. Anyone have BMW document ID that discusses this?

I am not sure it is worth bringing it up since my tires appear to be evenly worn.

Bob Wilson

Hi,

Since my BMW i3-REx is in the shop for a 'broken driver side motor mount bolt', I have some questions:

alohart said:

. . .
Our 2014 i3 hasn't had its defective motor mount bolt replaced, so I can't offer any personal experience with the updated software. However, what apparently causes the motor mount bolt to crack or break is when the rotation of one drive wheel suddenly accelerates rapidly when the drive wheel briefly loses contact with the road (e.g., when driving over a curb, speed bump, etc.). When that rapidly spinning drive wheel hits the road again, the shock of its rotation suddenly decelerating can crack or break the motor mount bolt. Others have stated that the software fix adjusts traction control to prevent the sudden acceleration of a drive wheel. I'm not sure that any of us knows for sure the details of the fix, but it apparently hasn't changed the i3's performance, so you might not have very strong grounds for suing BMW.

Click to expand...

When I got the BMW i3-REx to Huntsville, the 'motor mount bolt' action was performed. So now I'm wondering what would have been done?

Would all of the bolt(s) have been replaced or just inspected and the software patch applied?

During the recent failure, the technician reported he was disconnecting the HV in the motor compartment and saw the broken bolt:

This suggests he would have been looking at the top of the body side of the transmission/motor mount to see one or more broken bolts.

These images suggest there are five bolts holding the transmission/motor assembly to the frame:


The top two should be visible but the lower three may be hard to see.

There is one additional support attached to the anti-sway bar:


In a good design, the bolts are 'mechanical fuses' that fail before damage to the frame or transmission/motor housing. But given the nature of this failure, I would like to know all bolts including the anti-sway bar ones have been replaced. For good measure, inspect the transmission/motor housing and body attachment points to make sure there is no damage.

As for the broken bolt, I've had to deal with them in the past and it is a b*tch! There are specialty tools used to back out the broken bolt part but it isn't fun. It certainly is not something I would want to do with the transmission/motor still in the car.

Looking at this YouTube, the strain, the motion inside the compartment, is impressive:
https://www.youtube.com/watch?v=p9fVuqh5yb0

After the car is repaired, I may look at ways to monitor/record the transmission/motor displacement.

Bob Wilson

Customer field use brought the potential for a broken motor mount bolt to their attention, and all affected vehicles are subject to the free replacement. The stated most common reason for their failure was/is going over a bump while accelerating fairly hard...the wheels unload, potentially speeding up considerably, then hitting the pavement, and rapidly decelerating. The S/W patch changed the logic that detects wheelspin so that the motor controller can catch that symptom sooner, and limit power, preventing that impact by limiting the acceleration.

I don't remember if the fix called for replacing all of the bolts, but I think it did. Then, they tweaked the software to help prevent it from happening again.

So, it's not really movement during normal driving, it's the shock generated by freewheeling then rapid deceleration.

If this was recently done, there were a bunch of other s/w tweaks applied at the same time. FWIW, while BMW used to give the dealers a list of the functions affected, they no longer do, so the dealers are unable to tell you. If you have a problem, they enter it in the computer, and corporate responds with the corrective action...might be s/w, might be an adjustment, might mean replace a part...they do not know in advance except for something like the bolts.

jadnashuanh said:

. . .
So, it's not really movement during normal driving, it's the shock generated by freewheeling then rapid deceleration.
. . .

Click to expand...

Fortunately, I have some recording accelerometers: http://gcdataconcepts.com/x2-1.html

These were left over from the Prius brake-pause investigation:



To have this happen six months after the bolt campaign makes me curious.

Bob Wilson

You probably won't see the acceleration/deceleration when measuring the vehicle's state...it's the rotational energy of the wheels when unloaded/in the air verses when they regain traction that produced the shock that gave issues with the motor mount. The unloaded wheel can accelerate rapidly and this is what the new software is supposed to catch and limit to prevent as severe of a shock. You'd need to be measuring the horizontal g-force as well as the vertical to get an idea of when a wheel was unloaded (unless it was slipping link discussed below). It's hard to be sure, but I do think the operation after hitting a pothole is slightly different now verses previously.

FWIW, I was backing uphill on Tuesday into a curbside parking space covered in snow. The car moved smoothly without spinning the wheels, but the traction warning lamp was flashing consistently. I do have winter tires on the thing, but even then, it was slippery.

jadnashuanh said:

You probably won't see the acceleration/deceleration when measuring the vehicle's state...it's the rotational energy of the wheels when unloaded/in the air verses when they regain traction that produced the shock that gave issues with the motor mount. The unloaded wheel can accelerate rapidly and this is what the new software is supposed to catch and limit to prevent as severe of a shock. You'd need to be measuring the horizontal g-force as well as the vertical to get an idea of when a wheel was unloaded (unless it was slipping link discussed below). It's hard to be sure, but I do think the operation after hitting a pothole is slightly different now verses previously.
. . .

Click to expand...

Source: http://www.gcdataconcepts.com/ham.html

• HAM-IMU
  
  • 3-axis accelerometer, gyroscope, magnetometer
    User selectable sample rates of 50, 100, and 200 Hz
    Quaternion orientation solutions based on accelerometer and gyroscope data

This one also has the magnetometer so I should also get some indication of power flow. They have already shipped it so I should see it sometime next week.

I also stopped by the shop:

The motor/transmission attachment broke. Formerly of a structural plastic, the replacement is an aluminum frame. Regardless, the remaining bolt fell to the floor:



The fracture comes from the stress concentrators from the thread. Maximum stress on a thread will lead to stress concentrators, fractures, and eventually, work induced failure.

The stress indicates a fore-aft stress, not a length torsional failure. In effect the ordinary motion resulted in the bolt shearing from front-back motion. Confirmation comes from taking a photo of the body anchor and verification that the final fraction left a vertical bar.

Bob Wilson

At the shop, I was able to take more photos including the left and right body anchor points:



I had a 2" receiver hitch installed to carry my wife's folding wheel chair on the back:



When they drop the transmission/motor and REx assembly, these parts may have to come off. I'll contact the vendor to get a copy of their installation instructions.

We also saw four 'pad' spots on the battery suggesting someone in the past raised the car by lifting on the battery. OWCH!!!

Bob Wilson

I've read some posts about a recall for the motor mount screws (bolts are technically a screw that uses a nut for tightening) but I'm wondering if I can have the dealer replace these if I haven't received an official recall letter from BMW, or if there is an official recall. I did receive a letter from BMW recently about bringing the car in for a software update related to the accuracy of the SOC display so I'd like to have these replaced when I bring the car in for that. Wondering how reluctant the dealer will be to do this if I haven't received an official letter from BMW about this. I'm also curious if the letter I received is related to the fixes from the November 2015 software update, which I've already had done by the dealer.

It depends on when your vehicle was manufactured...the fix was applied somewhere in the production history so there are obviously some vehicles that left the factory with the latest tweak and therefore don't need anything. The dealer should check your vehicle against the database of required updates whenever you take it in for service. FWIW, some s/w updates won't be applied unless you have an issue that was addressed in a change, though. If you do get new software, you get everything updated, and some updates are applied to everyone, all of the time.

brorob said:

I've read some posts about a recall for the motor mount screws (bolts are technically a screw that uses a nut for tightening) but I'm wondering if I can have the dealer replace these if I haven't received an official recall letter from BMW, or if there is an official recall.

Click to expand...

I did not receive any communication from BMW telling me that our July, 2014, BEV had a defective motor mount screw that needed to be replaced, a serious problem compared with the only letter I have received from BMW telling me that our i3 needed its software updated to increase the range estimation accuracy, a very trivial problem. Having the VIN of your i3 would be sufficient for a BMW service department to determine whether your i3 needs to have a defective motor mount screw replaced. Replacing this motor mount screw should not generate any resistance from your dealer.

When I took our i3 in for its first scheduled maintenance 2 years after it was manufactured, I told the service representative that I needed the defective motor mount screw replaced during this same service call. The service representative looked up the VIN of our i3 and confirmed that the motor mount bolt needed replacing. There was no pro-active effort by BMW which is disappointing. I wonder whether the screw would have been replaced had I said nothing about it.

Also disappointing is the structural plastic piece that broke in bwilson4web's i3 and is being replaced by an aluminum piece. I'm pretty certain that this plastic piece was not replaced when the motor mount screw was replaced in our i3, so our i3 still has the plastic piece that is apparently prone to break and for which an updated stronger piece has been designed. All i3's should have had this improved aluminum piece installed when the motor mount screw was replaced. I fear that the original plastic piece will break after our warranty has expired resulting in a very expensive repair. The more I read about these i3 problems, the more likely I am to sell our i3 when its warranty expires despite taking a huge depreciation loss.

I went back the original photo (actually I have three) and focused on just the broken motor mount bolt:

• No evidence of a mount fracture as the top surface does not show new material.
• The broken off bolt section is visible extending out the right.
• It looks like there may be a metal insert in the structural plastic.

I was thinking about this the other day and realize my warranty will be ending in about 18 months. I am thinking I may want to bring the car in and have the mount bolts replaced so I get to keep the old ones for analysis. In particular, a dye penetration test to see if there is evidence of early stress fractures.

The other alternative is to order the bolts; have them tested, and; swap them myself. One speculation is to grind the center section so there are no threads at the maximum shear point. Except the act of cutting the initial threads has the potential of making the initial surface defects. If I grind off or use a lathe to turn off the middle threads, I'll have to dye test them afterwards.

Upon further reading, it appears there may be ways to improve thread stress performance by adjusting the nut characteristics. Apparently the first thread is easily over stressed but by cutting the nut with a different profile, the peak stress can be spread across the bolt threads '30%' reduced. So it makes sense that the part affixed to the transmission/motor may be the key.

Bob Wilson