Dreaded Drivetrain Fault 2019 120aH BEV (not REX)

[g0rsq]

After 2 months ownership I have got the dreaded Drivetrain Fault message.
On dash it says HV fault, but is OK to drive, but to get it looked at before further damage occurs.

On ISTA i get four messages (after clearing all codes), three that are recorded:-

22280F, 21F0E4, 21F0E3

and one permanent fault 030F02

All four say "High-Voltage electrical system: insulation resistance below fault, or warning threshold.

I ran the test-plan for the active code and got a reading of 266 kOhm.

Continuing the test it appears the fault is NOT in the battery, but I can not diagnose further.

So my presumption is the fault is either in the cable or the EME.

I understand the cable can give issues (this is a 2019 car so probably not one of the faulty parts) but is there any way to further diagnose before replacing it, or what would anyone recommend before this, or taking it to a specialist? Maybe I can disconnect cable both ends and use a Megga meter to check earth leakage.

Car should have a newish 12V battery (told by previous owner) and it registered 14.8V in ISTA, but seemed to still be charging at 8 amps.

Car still drives and charges (AC) without issues.

 

[alohart]

Have you been driving on wet roads lately? If so, maybe water intruded into a HV connector. If the fault goes away after several dry days, maybe you have a clue to examine HV cable connectors (unfortunately, there seem to be many).

 

[g0rsq]

Have you been driving on wet roads lately? If so, maybe water intruded into a HV connector. If the fault goes away after several dry days, maybe you have a clue to examine HV cable connectors (unfortunately, there seem to be many).

I have been driving it on wet roads since I bought it!!!!

When I picked it up, a lot of roads were flooded (3 to 4 inches max) and I do not think it has stopped raining since....

I am hoping it is just dampness, but even if it is, there must be a problem, as it is not normal.

Today the fault actually cleared, for about 15 mins, but returned near end of journey.

I guess I need to get under the car and check the main cables going to the battery. This cable is only £200 new so may be worth replacing as a first step. I think this is the only cable with exposed connections, but moisture could be in the form of condensation, especially as very little heat generated when running.

 

[DrSealer]

Have you been driving on wet roads lately? If so, maybe water intruded into a HV connector. If the fault goes away after several dry days, maybe you have a clue to examine HV cable connectors (unfortunately, there seem to be many).

After 2 months ownership I have got the dreaded Drivetrain Fault message.
On dash it says HV fault, but is OK to drive, but to get it looked at before further damage occurs.

On ISTA i get four messages (after clearing all codes), three that are recorded:-

22280F, 21F0E4, 21F0E3

and one permanent fault 030F02

All four say "High-Voltage electrical system: insulation resistance below fault, or warning threshold.

I ran the test-plan for the active code and got a reading of 266 kOhm.

Continuing the test it appears the fault is NOT in the battery, but I can not diagnose further.

So my presumption is the fault is either in the cable or the EME.

I understand the cable can give issues (this is a 2019 car so probably not one of the faulty parts) but is there any way to further diagnose before replacing it, or what would anyone recommend before this, or taking it to a specialist? Maybe I can disconnect cable both ends and use a Megga meter to check earth leakage.

Car should have a newish 12V battery (told by previous owner) and it registered 14.8V in ISTA, but seemed to still be charging at 8 amps.

Car still drives and charges (AC) without issues.

Have you found where was the fault in the end? As I am having same issue with my 330e after very heavy rain, I have checked all the cables all seems to be good

 

[g0rsq]

Have you found where was the fault in the end? As I am having same issue with my 330e after very heavy rain, I have checked all the cables all seems to be good

I plan to investigate further this weekend with my insulation tester.

I have done some research on these cables and they are very interesting.

The cables are actually co-ax cables with a metal screen on each conductor. This metal screen is insulated from the body (earth) of the car, but is monitored by the EME for voltage.

The actual conductors are inside this screen and also insulated from it.

Leakage can therefore be measured between the inner conductor and the screen and flag a fault.

This means any fault will be inside the cable, and not obvious looking on the outside.

My plan is to measure the insulation between inner conductor and the cable screen at various points, disconnecting cables, to find the fault.

Hopefully i will locate it.

I am an industrial Electro-mechanical engineer, working on 600VDC servo motor systems, many more times powerful than the i3, but first time with these coaxial power cables...

 

[DrSealer]

I plan to investigate further this weekend with my insulation tester.

I have done some research on these cables and they are very interesting.

The cables are actually co-ax cables with a metal screen on each conductor. This metal screen is insulated from the body (earth) of the car, but is monitored by the EME for voltage.

The actual conductors are inside this screen and also insulated from it.

Leakage can therefore be measured between the inner conductor and the screen and flag a fault.

This means any fault will be inside the cable, and not obvious looking on the outside.

My plan is to measure the insulation between inner conductor and the cable screen at various points, disconnecting cables, to find the fault.

Hopefully i will locate it.

I am an industrial Electro-mechanical engineer, working on 600VDC servo motor systems, many more times powerful than the i3, but first time with these coaxial power cables...

I have checked insulation resistance on some of the cables where I could access with megohmmeter all readings were way above bmw recommended threshold. I still have to check KLE unit cables so hopefully fault lays somewhere there

 

[g0rsq]

You can check insulation in each component, such as EME KLE etc, but remember you are testing between the DC conductors and the cable screen, not vehicle earth.

On my car the warning as now gone and not been seen since. Last think I did was to use compressed air to blow in and around all HV cables and connectors that were accessible, cleaning dust and leafs.

One other thing to note, this fault only started a few days after disconnecting the HV battery, as i needed to disconnect the 12V battery to remove the drivers seat. Now after disconnecting the HV battery for a second time, fault has gone....Coincidence...Maybe, but at moment I am happy.

 

[DrSealer]

You can check insulation in each component, such as EME KLE etc, but remember you are testing between the DC conductors and the cable screen, not vehicle earth.

On my car the warning as now gone and not been seen since. Last think I did was to use compressed air to blow in and around all HV cables and connectors that were accessible, cleaning dust and leafs.

One other thing to note, this fault only started a few days after disconnecting the HV battery, as i needed to disconnect the 12V battery to remove the drivers seat. Now after disconnecting the HV battery for a second time, fault has gone....Coincidence...Maybe, but at moment I am happy.

Have checked KLE cables yesterday, they were a bit wet on the outside even though the car been parked for more then a month, and quite a bit of corrosion around where the cable plug surround sits. Cleaned it all up, tested insulation resistance between cables and their shields (cable screens) all with very good resistance.

I will try to same on the auxiliary heater again, as first time when I did I tested only between + - and body.

It’s just weird that the car since the fault first appeared haven’t been affected at all, drives like nothing is wrong, except a drivetrain fault on the screen, and there was one moment when the fault disappeared for few hours while driving, but it came back, so it’s been parked since

 

[g0rsq]

The high voltage system is double insulated from chassis ground.
The system is checking resistance between the high voltage terminals and the high voltage ground!

Mine failed again today, but weather is damp and cold, and car not used in a week.
If it's not raining tomorrow will have a quick test of my system.

edited to correct an error in description.

 

[ksnax]

Have you considered the resistive heater as a cause? That is something that Wisely Automotive has noted as a potential fault cause as it confuses the situation with heat pump equipped cars. E.g., on low demand where only the heat pump is engaged, heat and driving appear to be normal with no error produced from startup, but when the resistive heater is engaged, it produces a fault as it draws it's power directly from the HV battery.

The key factor with this is that heat seems to work fine because the heat pump is not affected.

 

[g0rsq]

Have you considered the resistive heater as a cause? That is something that Wisely Automotive has noted as a potential fault cause as it confuses the situation with heat pump equipped cars. E.g., on low demand where only the heat pump is engaged, heat and driving appear to be normal with no error produced from startup, but when the resistive heater is engaged, it produces a fault as it draws it's power directly from the HV battery.

The key factor with this is that heat seems to work fine because the heat pump is not affected.

Today i did some testing (it was cold, but not raining!)
I isolated the HV supply from the battery.

I then disconnected the battery cable from the top of the EME and did a continuity test on the main cables to the battery (these cables have been revised for this reason) but they tested perfect.

I then carries out an insulation test at the connector on the EME, which showed 330kOhm to ground. So fault was on the HV system somewhere.

I removed the other large connector from the top of the EME and again this showed the fault when testing the EME, not the cable side.

I next unplugged the three small cables on the side of the EME, which cleared the fault when testing at the main connectors on the EME.

TIP to remove these pull the black tab down, so the two tabs can be pushed in. use a small cable tie around the plug to push in the two tabs, then pull the plug off. trying to press both tabs and pull in the small space is difficult. see picture

I tested each of the three small plugs, and found the middle one to be almost short circuit at 500V. The other two were OK.

This is the long cable that goes to the front, and, @ksnax, as you guessed to the auxiliary heater. (I do not have a heat pump on my car)

That's as far as I got, (needed to check AC system on my Mercedes SL500 while I had light) so it is either the cable, or more likely the heater itself. This ties in with my observations that the heater is poor (it works, but not very warm).

So next weekend i will move to the front and prove it is the heater module or the cable.

 

[g0rsq]

Well next weekend is here, and here is latest on diagnostics.

From the front I removed HV cable from heater and used a Megameter to test the heater, and it is fine. So I tested back along cable and it showed virtual ground.
Disconnecting both ends of cable and testing to cable screen (Make sure not testing to vehicle earth like I did at first!) and sure enough it showed a near ground on one conductor to cable screen .

So it is a faulty cable, from EME to the heater.

£25 for used one on eBay or £100 for new one. New one on order.

Anyone replaced, or just removed, this cable. Hopefully it does not go over the battery! Any pictures or experience welcomed.

 

[Tecam]

Excuse my ignorance, but what is “EME”

 

[g0rsq]

Excuse my ignorance, but what is “EME”

"Electrical Machine Electronics"

Basically it is the electronic control unit that controls all the high voltage drive system. It sits on top of the main motor. The high voltage DC battery connects to it, and from this module the motor is powered, and the high voltage is distributed to the rest of the systems.

or £13,000 to you and me

 

[alohart]

"Electrical Machine Electronics"

Basically it is the electronic control unit that controls all the high voltage drive system. It sits on top of the main motor. The high voltage DC battery connects to it, and from this module the motor is powered, and the high voltage is distributed to the rest of the systems.

or £13,000 to you and me

It also includes the DC-DC converter that provides power to the 12 V system charging the 12 V battery when necessary.

I believe that earlier versions also include 1 on-board charger for charging the battery pack from AC mains power. I've read that this charger was moved to the KLE in later versions.

Lots of HV, high power electronics ($$$).

 

[alohart]

Anyone replaced, or just removed, this cable. Hopefully it does not go over the battery! Any pictures or experience welcomed.

I've seen a diagram showing all HV cables routed along the left(?) side of the battery pack compartment.

 

[g0rsq]

I've seen a diagram showing all HV cables routed along the left(?) side of the battery pack compartment.

Been looking at pictures on google (i3 pictures ) and cant find any showing the location/run of this cable.

However I suspect it runs behind the lower plastic side skirt, so removing this should show the cable, which would be along the side of the battery.

So this should be quite straight forward replacement.

 

[Dutchi3]

or £13,000 to you and me

That feels like a crazy amount. But if you are into High-End audio and have attended shows, you will see similar prices for sophisticated audio equipment like amplifiers or turntables and some folks buy those without a blink of the eye. So yes, sophisticated electronics has it's price.

 

[alohart]

However I suspect it runs behind the lower plastic side skirt, so removing this should show the cable, which would be along the side of the battery.

So this should be quite straight forward replacement.

Looks like it actually runs along the right side of the battery pack compartment, not the left side as I guessed previously. Replacing electric heater cable (attached):