2015 Model S unable to start messages.

[DaBoozer]

Hello all, first time posting but been following for some time.

I own a 2015(production 12/15) Model S 70. Around 6 months ago, veh gave error messages after charging at the house on a level 2 charger. Was running fine when I parked it the night before.
* Unable to Start
* Supply voltage low
* Power reduced

I have done the following checks.

12 volt battery tested good. Replaced it anyway with no change.
It will never close the contactors for the HV battery. Inspected all fuses in fuse boxes as well as junction box and all ok. Bought the T-can software and was able to communicate with several modules but limited on data I can see. Found multiple codes for HVIL failure. checked voltage of HVIL circuit at safety disconnect to find 12v on circuit. Tested resistance at several different points throughout the circuit to test to the modules 60 ohm resistors and all appear to be good. Can not find much information on the operation of the HVIL, but what I have found, appears the BMS should be sending out 12 volts and dropping at the 4 known resistors and measures voltage which should be around 4.8V back at the HV battery. I am understanding this correctly?

Any help or documents on operation or diagnosis would be very much appreciated.

Thanks in advance

 

[Gtech]

I attached some more info on the HVIL not sure if you already have this.

2 months ago I had the same issue and also HVIL issues but my drive unit failed.

 

[DaBoozer]

I will look at them. Thanks for the info and will update with results if I find the issue.

 

[DaBoozer]

I do have that document and it helped tremendously. The drive unit is one of the only things I haven't checked the resistance of. Will check it shortly.

 

[terofin]

Hello all, first time posting but been following for some time.

I own a 2015(production 12/15) Model S 70. Around 6 months ago, veh gave error messages after charging at the house on a level 2 charger. Was running fine when I parked it the night before.
* Unable to Start
* Supply voltage low
* Power reduced

I have done the following checks.

12 volt battery tested good. Replaced it anyway with no change.
It will never close the contactors for the HV battery. Inspected all fuses in fuse boxes as well as junction box and all ok. Bought the T-can software and was able to communicate with several modules but limited on data I can see. Found multiple codes for HVIL failure. checked voltage of HVIL circuit at safety disconnect to find 12v on circuit. Tested resistance at several different points throughout the circuit to test to the modules 60 ohm resistors and all appear to be good. Can not find much information on the operation of the HVIL, but what I have found, appears the BMS should be sending out 12 volts and dropping at the 4 known resistors and measures voltage which should be around 4.8V back at the HV battery. I am understanding this correctly?

Any help or documents on operation or diagnosis would be very much appreciated.

Thanks in advance

hi, did you get any help? i have same problem, HVIL loop is ok, AC compressor was faulty and i replace it, but still same errors...

 

[terofin]

my problem was f027_repeatedly, have to reset it with t-diag