What is the problem with error BMS_f036?

[tanzui]

2018 Mode X 75D has 3 error codes
BMS_w036_HVIl
BMS_f036_HVIl
BMS_w125_HW_BMS_Bind_Mate
Measure the HVIL resistance at 180Ω, BMS HVIL has no voltage.
After removing the BMS, power up repeatedly to measure the OUTPUT of BMS HVIL. There is no voltage, is this normal? What is the normal voltage? Can you tell me if you know? Thank you very much!

 

[Travieh5]

I’ve been dealing with the bms_f036 code in my 2017 MX. I’m in the process right now of ordering and replacing the HV rapid splitter harness. It goes to front motor, rear motor and charge controller. The hv positive line had a tear in it at the rear motor. Hoping replacing that harness removed the code. My MX will not even charge because of the fault.

 

[tanzui]

I’ve been dealing with the bms_f036 code in my 2017 MX. I’m in the process right now of ordering and replacing the HV rapid splitter harness. It goes to front motor, rear motor and charge controller. The hv positive line had a tear in it at the rear motor. Hoping replacing that harness removed the code. My MX will not even charge because of the fault.

I have solved the problem. It was because the high voltage interlock pin on the high voltage rapid branch connector was unable to contact the lower plug-in socket. I have replaced it. Thank you very much.

 

[Travieh5]

I have solved the problem. It was because the high voltage interlock pin on the high voltage rapid branch connector was unable to contact the lower plug-in socket. I have replaced it. Thank you very much.

Awesome to hear. Mine should be in soon. Question though, did the bms_f036 code go away after the fix or did you have to clear it with a coder? (T-daig/Loki/toolbox)

 

[JCM_76]

Hi,

I have the same faults/warnings (w036, f036, w126) on my 2014 Model S P85+, the contactors are open.

What would you recommend me to find the issue?

Best regards,

 

[Travieh5]

I have found these two links to trouble shoot the issues to figure out if it’s not closing or if something else is wrong. You can see the x035 to be the pin that closes in the hv rapid splitter. On the low voltage side it’s pin 11 that needs to be checked for power/ohms

https://static.nhtsa.gov/odi/tsbs/2014/SB-10052449-4313.pdf

https://static.nhtsa.gov/odi/tsbs/2013/SB-10052460-6095.pdf

 

[JCM_76]

@Travieh5 thanks for your comments.

Would be voltage at the pin 11 of x35 connector if the contactors are open? As I understand if the contactors are open the HVIL are power off, so, in order to figure out if the loop is closing it is needed to measure resistance between the pins to ground, according to the document you send, not voltage, right?

Thanks in advance for your answer,

 

[Travieh5]

@Travieh5 thanks for your comments.

Would be voltage at the pin 11 of x35 connector if the contactors are open? As I understand if the contactors are open the HVIL are power off, so, in order to figure out if the loop is closing it is needed to measure resistance between the pins to ground, according to the document you send, not voltage, right?

Thanks in advance for your answer,

I believe it still may. I still have yet to try it. (My MX is outside and weather hasn’t been nice.) the hv side isn’t connecting but the 11 pin should be one of the low voltage harnesses going into battery on the passenger side. I’ve read about those pins inside either corroding or the pin pulls out of the harness enough to not make contact with battery side. I believe that low voltage runs to all the hv parts. A couple things I’m checking this weekend. 1: my pyro fuse hasn’t blown. 2: the ohms and if there is voltage on pin 11. It f not, might check the hvil fire cord harness in the front. 3: the rapid splitter I newly installed is seated all the way and that the two round pins in the middle don’t have arching on them. 4: the battery connector for the hv rapid spitter looks good. 5: with rapid splitter off, checking ohms on hv lines to rear motor and the rear motor itself. It’s sucks that Tesla can’t isolate the rapid splitter so that if 1 high voltage item goes bad, the car bricks.

 

[Travieh5]

I believe it still may. I still have yet to try it. (My MX is outside and weather hasn’t been nice.) the hv side isn’t connecting but the 11 pin should be one of the low voltage harnesses going into battery on the passenger side. I’ve read about those pins inside either corroding or the pin pulls out of the harness enough to not make contact with battery side. I believe that low voltage runs to all the hv parts. A couple things I’m checking this weekend. 1: my pyro fuse hasn’t blown. 2: the ohms and if there is voltage on pin 11. It f not, might check the hvil fire cord harness in the front. 3: the rapid splitter I newly installed is seated all the way and that the two round pins in the middle don’t have arching on them. 4: the battery connector for the hv rapid spitter looks good. 5: with rapid splitter off, checking ohms on hv lines to rear motor and the rear motor itself. It’s sucks that Tesla can’t isolate the rapid splitter so that if 1 high voltage item goes bad, the car bricks.

@JCM_76 Well some update as I think about my issue tonight.
1st: the instructions say to pull the hvil loop when doing this test so you will have voltage at pin 11.
2: all of my rear components seem to checking out ok. I didn’t have time to start ripping apart front to check up there.

Some stuff I tried and was thinking about. So I was sitting in the car and all I have is bms_f036 code untill I hit the brakes and get all the low voltage codes. I did 12v reset and instead of hitting brakes I turned on heater max, after about 5/10 seconds the codes popped up again. I did same thing with heater and 5/10 for it to happen again. After resetting 12 volt one last time I was just sitting in the car with no heat/ac or foot on the brake. The codes would come on randomly for a couple sec then off for 10/15 sec, then repeat. My thought is, either the dc-dc is going bad or the battery heater has failed. Correct me if im wrong but if I’m in the car “idle” we will say, the only high voltage items that would try to run is the dc-dc and the battery heater sense it’s about 28 degrees Fahrenheit where I am. The only other issue that I’m saving for last resort is the battery bms welded open. (Really don’t want to drop the battery out.) I hope you’re having better luck then I am. I’ll keep you posted

 

[Travieh5]

so all my hv component seem fine. Went into the service side and found this in the high voltage tab. Hvil is green light but state is red light. So now I have to figure out if my Bms is bad or the cells are bad in the battery. Looks like I will be dropping my battery to check it.

 

[JCM_76]

Hi, HVIL on the battery side is OK. I don´t sure but I think that the HVIL on the battery side is the circuit from the 20mA constant current source from the battery to the switch on the socket that connects to the HV rapid mate,,, can someone confirm it or correct it if I wrong?

Anyways, I don't think the problem could be inside your battery pack. I have exactly the same issue in my Model S, I checked the internal cell voltages with the "scan my tesla" app and they looked pretty flat with a very low bit of umbalance between cells (less than 6mV, see pictures attached), my battery pack have a SOC of 79.4%, that have been be constant in the last three months (the time my car has been sitted since it failed) and total pack voltage of 383V...

I almost sure that your battery pack is OK since you have a good HV internal isolation, neverthless I recommend to check your battery pack cell voltages,

I am checking the HVIL circuit diagram of my Model S (no sure if is the same as the model X...) and I figured out that there's a 20mA current from the battery pack that should flow thought the HV responder loop, backing again to the pack and flowing out again to the rest of the HV components (charger, HVJB lid switch, AC compressor, PTC, etc...),

In my case I followed the HVIL circuit according to the diagram, checking the resistance in the pins of each connector... until now all the resistance readings are according to the expected values, BUT... I'm haven't checked yet continuity in lid switchs at the HVJB, CHG and FCJB as well as the first responder loop... did you do that?

Our BMS state are "FAULT" precisely because somenthing in the HVIL is open... it could be a bad connector or switch or even the interlock pin on the high voltage rapid branch connector could unable to contact the lower plug-in socket located inside the battery pack...

Let's find out...

I plan to work on my Model S tomorrow morning, I will test the rest of the HVIL, hoping to find the faulty element... If I don't, then I plan to drop the battery pack to check the interlock pin on the HV rapid mate... I keep you informed on my findings!

Best regards,

 

[JCM_76]

Hi,

This is just to tell you guys that I already fixed my car, that's a really good news!

It only took a little push on the upper side of the HV branch connector (rapid mate) to "accomodate" the blades and pins on the battery pack, inmediatelly BMS_w126 and BMS_f036 disappeared,..

Instead of the fatal faults disappeared, the car still has some warnings that need attention for a later analysis,

Best regards and thanks for your help!

JC

 

[Travieh5]

Hi,

This is just to tell you guys that I already fixed my car, that's a really good news!

It only took a little push on the upper side of the HV branch connector (rapid mate) to "accomodate" the blades and pins on the battery pack, inmediatelly BMS_w126 and BMS_f036 disappeared,..

Instead of the fatal faults disappeared, the car still has some warnings that need attention for a later analysis,

Best regards and thanks for your help!

JC

Awesome to hear. Now when you say push, I’d that from the pins in the rapid splitter or the battery? I’m going to give that a go this weekend. That was going to be my first check.

 

[JCM_76]

Awesome to hear. Now when you say push, I’d that from the pins in the rapid splitter or the battery? I’m going to give that a go this weekend. That was going to be my first check.

Try to push gently but firmly the rapid splitter just in the ground screw, Hope this helps!

 

[Travieh5]

Try to push gently but firmly the rapid splitter just in the ground screw, Hope this helps!

Sadly that didn’t work for me. Does your rapper splitter bolt to the car like the x does? So hard to give it a little push. I did check my hv responder loop and it’s “not” getting 20ma. I still think it may be my rapid splitter but in the batter side. Maybe the female ends of those plugs pushed in. I got a continuity check on my pyrofuse and it was good. I’ll have to recheck it for voltage I think though. Now I’m trying to hunt down why I’m not getting 20ma through the low voltage side.

 

[Travieh5]

Wondering as well. When I took my rapid splitter off and readjusted it. I forgot to put the responder loop back on. I did lose the f036 but had the f062 and f033 which normally lead to the loop not being connected. So maybe my rapid mate is fine and there is a bad component.(motor,dcdc/heater,ect). I also did find out that nothing will get 20ma if there is a hv fault on the screen. So looks like I’ll be hunting down what hv part is bad to replace this weekend.

 

[JCM_76]

Wondering as well. When I took my rapid splitter off and readjusted it. I forgot to put the responder loop back on. I did lose the f036 but had the f062 and f033 which normally lead to the loop not being connected. So maybe my rapid mate is fine and there is a bad component.(motor,dcdc/heater,ect). I also did find out that nothing will get 20ma if there is a hv fault on the screen. So looks like I’ll be hunting down what hv part is bad to replace this weekend.

Wich faults are you getting right now?

Do you have BMS_W126?

Did you measure your car´s internal/external isolation? I recommend you to measure the isolation of each component: PTC, AC compressor, battery coolant heater and compare it with the expected value...

Please keep us informed about your findings,

 

[Travieh5]

Wich faults are you getting right now?

Do you have BMS_W126?

Did you measure your car´s internal/external isolation? I recommend you to measure the isolation of each component: PTC, AC compressor, battery coolant heater and compare it with the expected value...

Please keep us informed about your findings,

Just the bms_w036 and bms_f036. I get the di_u014;gtw_w018 when I press the brake. I get my reader on Wednesday to check the batter on the “scan my Tesla” app. I did a check on the components and the are all getting well above the ohms rating on my snap on multimeter. I unbolted the rapid splitter and tried getting it set perfect and still that code. I’m still pretty sure it’s the rear motor. I believe I have an older style because i do not have the port to see the dc side of the motor/inverter. It’s a three holes port on the back of the motor. Guessing the 3 bolts I can see are the ac side of the inverter. I noticed a little gear oil coming from the seal of the cv axle meets housing, so I’m guessing something is compromised inside the motor, I didn’t have any high voltage issues untill I dropped the rear sub frame and removed motor to get the subframe fixed after a upper control are broke off and damage frame. Once I got everything back in, the code came up. So kinda just going on what I’ve touched before this code started,

 

[JCM_76]

Did you ckeck if there's voltage in the HVIL?

I think you have something disconnected in the HVIL, because your are getting only w036 and f036 codes, no more codes related with your DU, so that it isn't likely that your DU has faulted... I think!

I'm not sure if the MS HVIL circuit match with MX, but you can use the HVIL diagnostic guide to check the voltages in the loop, any voltage deviation will conduce you to the faulted part...

Hope this helps,

JC

 

[Travieh5]

Did you ckeck if there's voltage in the HVIL?

I think you have something disconnected in the HVIL, because your are getting only w036 and f036 codes, no more codes related with your DU, so that it isn't likely that your DU has faulted... I think!

I'm not sure if the MS HVIL circuit match with MX, but you can use the HVIL diagnostic guide to check the voltages in the loop, any voltage deviation will conduce you to the faulted part...

Hope this helps,

JC

I’ll try and check when I can. Most of that is the same for ms to mx.couple connectors in different places and everything under car instead of seats. I know there are two low voltage harnesses coming from the back side of battery next to hv rapid splitter. The both run into the car, thinking to the mc and everything before heading through the loop.I did a quick test on the fire loop in front and wasn’t getting any voltage to there. I’ll see if the low voltage harness from battery are sending out the 4.8volts. Or I’m im getting ohms if it’s off. I got my reader today and I’m getting 4volts over all my cells which is good. I’m wondering it’s an error or need to cycle the battery cause it’s says my full pack is a 75kwh battery when I have a 90d.