1. Introduction
There could be many reasons for this alert.
1.1 Why its important to have isolation in electric car?
High Voltage systems are mounted on car chassis. There must be a minimum electrical isolation/resistance in between High Voltage System and Car Chassis to ensure safe car operation.
There is monitor which is installed in battery, which measure periodically the resistance between the high voltage conductors and chassis.
1.2 What is BMS (Battery Management System )?
"Battery Management System is a printed Circuit board assembly, which communicates with the BMSs (each module) and the powertrain/vehicle.
BMS performs the isolation test.
1.3 Type of Isolation
There are internal and external isolation.
1.3.1 Internal Isolation
- BMS_a123_SW_Internal_Isolation
1.3.2 External Isolation
- BMS_a035_SW_Isolation
- BMS_w035_SW_Isolation
- BMS_a151_SW_external_isolation
1.4 What will happen?
2. Diagnosis
This alert could come because of isolation issue. It need to check additional alerts to find out the cause of this alert.
It could be possible to find out the exact cause via Remote Diagnosis, Service Mode.
2.1 How to check additional alert
It could be possible to find out exact cause via Remote Diagnosis, Service Mode. In case, you need support for diagnosis. Please contact us.
2.2 Remote Diagnosis
Please read more details about Remote Diagnosis in another guide (How to do, Cost etc.) Link If you need support. Please contact us.
2.3 How to do isolation diagnosis in Service Mode
It could be possible to do self diagnose via Service Mode.
How to read service alerts in Service Mode
- On the touchscreen, click Controls > Software
- Touch and hold the large word "MODEL" for 2 seconds and then release.
- Enter "service" as access code.
- After clicking on Service Alerts. You can read service alerts. If there is anything wrong with car. It will show in active alerts.
Service > Battery > High Voltage
If everything is good. You will see green circles.
In case, if there is any High Voltage issue. You will see low resistance value and red circle.
In case if you need Online Support for diagnosis. Please Contact Us.
Please read more details in another guide (How to do diagnosis) Link
In case, If you need support for diagnosis. Please Connect Us.
If you need support. Please send us Service Alert Screenshot via Contact or Whats App +49 (0) 15226242038. We will be happy to help you to explain alert and how could be fixed, cost, support for fixing if possible online support or to organize an appointment with independent affordable workshop.
Depend on alert/fault code, car might need to be repaired/serviced.
3. How to Fix it
3.1 Software Issue
Restart Touchscreen
Restarting the touchscreen could resolve the issue. Please read more details in another guide (how to do). Link
Powering Off the Car
If restarting the touchscreen have not resolved the alert/issue. You could try Powering Off the car.
- Please shift car into park
- On the touchscreen please touch Controls > Safety > Power Off
- Please wait for at least for two minutes without interacting with the car. Please do not open the doors, touch the brake pedal, touch the touchscreen etc.
- After 2 minutes, please press the brake pedal or open the door to wake the car (Source Tesla)
Software Update/Bug
There could be issue with Software/Bug. Please make sure that the car has latest software. If not, you should update and install latest software version. Please have a more details about Software update in another guide (how to do it). Link
3.2 Physical defect of the insulation material
There could be physical damage to High Voltage cables, bus bars, and connectors.
3.3 Contamination
Contamination (of any size, e.g. dust, bolts, etc.), or moisture. Please have a detail look in another guide about Water Ingress/Moisture. Link
3.4 Hardware
There could be issue with Hardware. High Voltage Component/part with isolation breakdown need to identified and faulty/damaged part/parts need to be replaced/repaired.
3.4.1 Drive Unit
One of reason could be issue with Drive Unit. More details about drive unit repair in another guide. Link
Model S/X with Large Drive Unit
In case if you you have Model S/X with Large Drive Unit. It could be common leakage issue. Please find more details in another guide. Link
3.4.2 PTC Heater
One of reason could be issue with PTC Heater. Please check more details PTC Heater in another guide. Link
3.4.3 AC Compressor
One of reason could be issue with AC Compressor. More details about AC Compressor repair in another guide. Link
3.4.3 Battery Coolant Heater
One of reason could be issue with battery coolant heater. Please check out more details about battery coolant heater in another guide. Link
3.4.4 HV Harness
One of reason could be issue (damage/faulty etc.) with High Voltage Harness.
3. Find and book best Workshop to fix Isolation issue
If you are looking for Workshop who is expert to fix such issue with best price. Please contact us with details in which country/city, are you looking for. Contact to Fix Isolation Issue
4. Alert Code
Possible alert code
- BMS_a035_SW_Isolation
- BMS_w035_SW_Isolation
- BMS_f035_SW_Isolation
- BMS_a151_SW_external_isolation
- BMS_f151_SW_external_isolation
- BMS_a123_SW_Internal_Isolation
BMS has detected that HV isolation is too low while contactors are closed
- BMS_f151_SW_external_isolation
- BMS_w151_SW_external_isolation
4. Online Support/Help
In case if you need any support or have any question. We will be happy to provide you Online/Remote Support. Please Contact Us.
5. Cost
Cost could vary depend on issue, type of workshop, location. If you are looking for online support or affordable independent workshop. Please free to contact us or have a look in Price List
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FAQ
1. Can i reset the alert?
It is recommend not do reset alert as long issue is not repaired.
Source : Tesla NHTSA, Isolation Procedure Isolation/Insulation Test
