1. Introduction
This is generic alert and there could be many reasons for this alert. In this free guide, you will get information about how to diagnose the exact cause of this alert, what could be the reasons for this alert, how to fix it, How much it cost to fix, How to get online support, Find and compare best affordable workshop in your region and book an online appointment to fix alert, Information about spare part number and name and buy new and used spare parts with best price etc.
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 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
Some of alert could come because of software bugs. Some of alert could resolve after restarting the system, software update/reinstall. To fix some of alerts, car might need hardware repair.
3.1 Restart System
Some of alert could resolve after restarting the touchscreen or power of the car.
Restart Touchscreen
Firstly, you could try with soft reset (restart touchscreen)
How to restart soft reset (restart touchscreen)
- Please shift car into park.
- Hold down both scroll buttons on the steering wheel until the touchscreen turns black.
- Please wait approximately 30 seconds for the touchscreen to restart.
Please read more details in another guide (how to do). Link
Powering Off the Car
If soft reset (restart touchscreen) have not resolved the alert/issue. You could try hard reset (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)
3.2 Software issue
Some of alert could be related to software issue.
Software Bug and Glitches
One of reason could be problem with software bug and glitches. Did you get this alert after updating recent software version? If yes, it could be related with software bug and could resolve with future software update. Please send us Service Alert screenshot. So we will inform you if it could be related to software bug. Link
Firmware not updated
One of main reasons could be that firmware is not updated. Have you checked recent update and updated to recent version? If not, we recommend you to do that. Please read more details in another guide. Link
Hardware Issue
There could be some hardware issue/faulty. Some of common hardware issues could be followings:
Recent Repair/Service
Did this alert pop up after recent repair/service? If yes, please let us know which repair/service was done recently. Some alerts could pop up if repair/service is not done in proper way. If system/alert has not be reset. Did you use aftermarket/used part?
3.2 Physical defect of the insulation material
There could be physical damage to High Voltage cables, bus bars, and connectors.
3.3 Contamination
If there is any contamination (of any size, e.g. dust, bolts, etc.), or moisture. This alert will pop up. Please have a detail look in another guide about Water Ingress/Moisture. Link
In case if you have model S/X with large drive unit. There could be more chances that your car has coolant leakage in inverter. It could be easily checked be removing wheel speed sensor. Please read more details (how to check, how to fix, cost etc) in another guide. Link
3.4 Hardware
There could be issue with Hardware. High Voltage Component/part with isolation breakdown need to identified and faulty/damaged part 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
How to troubleshoot isolation fault
- Physical defect of the insulation material
- Contamination (of any size, e.g. dust, bolts, etc.)
- Moisture
If you troubleshooting for isolation. Please check for any signs of moisture or physical damage to HV cables, bus bars and connectors.
High voltage component with isolation breakdown need to be localized and faulty/damaged component need to repaired/replaced.
- Measure isolation at HV Component
- Need to inspect connector for moisture or contamination.
Please have more details. Link
Donation/Support
If you feel you have benefited from this guide. Please consider donation, which will help us to create more such free guide for you. It will also show us that this guide was helpful for you.
Comment
Please leave us comment if you have any questions, if you would like to add/edit/delete some content in guide, if you would like to have guide on any another topic etc.
Share this guide Link
Please feel to share this guide/website link.
Frequently Asked Questions (FAQs)
1. Can I do at Local Workshop, Independent Tesla Workshop?
Yes, you can. However, please make sure that workshop knows how to work to Tesla Cars. If local workshop need any support. Please feel to contact us. We will be happy to provide online shop. You can also find workshop in our Workshop Locator.
2. Can I do it/repair yourself/myself (DIY)?
Some of repair could be done at DIY. In case, if you needed Tools, Know-How, Time etc. Please feel to contact us. We will be happy to provide you online support.
Note: Please do not work with high voltage components. If you do not need needed/proper Tools, Know-How etc. It could be dangerous.
3. Mobile repair service?
In some of cases, we could also provide mobile services. Please feel to contact us where are you located and what kind of repair are you looking for.
4. Car not under warranty, salvage, accident, flood, modified cars?
It is highly recommended to perform repair with independent workshop to save money.
5. Car under warranty?
In case, if your car is under warranty. It is recommended to cotact with OEM (Tesla Service Center).
Model S and X Owner under warranty
In case, if you have Model S/X. We could help you to get this repair under warranty. We have helped owners when Service Center rejected any issue in car. We had a customers, they had popping alert BMS_w035 and Service Center informed customers that there is not any issue in car. We helped customer to prove issue/defect in car. Later, customer got repair done, which saved around 6,000 dollars. In case, if you have issue. Please feel to contact us or book this service online. So we can help you to get repair before warranty expire and later you do not do pay for repair which could have done under warranty.
6. Alert still appearing after repair?
There could be many reasons. Some of reasons could be please make sure that repair was done in correct way, did you restart system after performing repair? did you Reinstall Firmware? Still appearing alert: Please free to Contact Us. We will be happy to provide you online support. Phone/Whats App +49(0)15226242038
7. 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
