1. Introduction
This is a generic alert, and there may be various reasons for its occurrence.
In this guide, you will get following information:
- How to diagnose the exact cause of the alert
- Possible causes for the alert
- How to fix and clear
- Estimated cost to resolve the alert
- How to get quick, easy and affordable remote support (Whats App +49(0)15226242038)
Book an appointment to resolve alert
You will also be able to find and compare the most affordable workshop in your region and book an online appointment to resolve the alert.
Spare Parts
Additionally, this guide provide information about spare part number and names. You can also buy new, used, remanufactured spare parts at best prices.
Remote Support
Feel free to contact us on Whats App +49(0)15226242038. We are happy to assist with remote diagnosis and provide support to clear alerts at affordable prices.
1.1 What is HVIL?
- High voltage interlock loop (HVIL) is a safety feature which protects people during the assembly, repair, maintenance and operation of a car.
- HVIL is electric signal which passes through all high voltage components.
- It is loop/circuit which will not allow the contactors to close when high-voltage connections becomes loose, disconnected or damaged.
- HVIL ensure that all HV connectors are connected before closing contactors.
- It also helps to protect driver and passengers in the event of accident.
- 20mA current passes through the loop.
1.2 HVIL Diagram for Model S/X
- HVIL circuit in red
- HV components in green
- HV Harness connectors
Potential causes of HVIL failures
BMS reports an HVIL (BMS_f036, BMS_f008) alerts if:
- the resistance changes, and the Voltage drop higher or lower than the maximum thresholds.
- intermittent connections (loose connectors and pins, intermittent open connections, out of spec parts etc.)
2. How to Diagnose
This alert may occur because one or more system or features are disabled or faulty. The exact cause of the alert can be diagnosed with the help additional alerts.
2.1 How to check additional alert
Additional alerts can be checked via Remote Diagnosis or Service Mode.
If you need support to check additional alerts, feel free to Connect Us Phone/Whats App +49(0)15226242038
2.2 Remote Diagnosis
Remote diagnosis will provide the exact cause of the alert. We offer Remote Diagnosis. To learn more about Remote Diagnosis
- How it work
- Cost
Please refer our another guide
If you need support, feel free to Contact Us Phone/Whats App +49(0)15226242038
2.3 Service Mode
In some cases, it can be be possible to find out the exact cause of the alert in Service Mode with the help of following details:
- Service Alerts in Service Mode
- Self-Diagnose in Service Mode
How to check service alerts in Service Mode
- On the touchscreen, click Controls (vehicle icon) > Software
- Touch and hold the large word "MODEL" for 4 seconds and then release.
- Enter "service" as access code (password).
- Clicking Service Alerts to view active and recent alerts. If there is any issue, it will appear in Service Alerts.
For more information, please refer another guide (How to do enable Service Mode) Link
If you need support for diagnosis, please feel free to Connect Us or Whats App +49 (0) 15226242038
Send us Service Alerts Photos to clear alerts
Please send us "Service Alert" photos via Contact or Whats App +49 (0) 15226242038.
We will be happy to help you to clear alerts.
How to diagnose
- DCDC HV connector test
- Loose logic connector test
- HV Connector continuity test
- Pin drag test
- Crim check
It is recommended to start testing with DCDC, FJB, secondary charger, Primary Charger, DU, HV Battery, Rapid mate.
Views > HV Electronics > HVIL Diagnostic
Views > HV Electronics > HVIL Monitor
HV Connector Disconnected, Unseated, Unlatched, loose, Out of spec fitting
Damaged crimps, pins or wiring
HVIL Pins damaged, bent or broken
Corrosion
Drag Test on each of the HVIL
PT_CHGVI_ADC_HVIL_I is below 18.83mA or above 20.8mA.
- BMS_hvilV
- DI_hvilCurrent
- DIS_hvilCurrent
What to check
- Check for a non-seated or non-latched HV connector
- Push and Pull the connector completely in and out
3. How to Fix
There may be hardware issue or faulty component. Some of common hardware issues include:
Recent Repair
Some alerts may appear if repair was not done properly or if system was not reset.
Did this alert appear after recent repair or service?
- If yes, please let us know which repair or service was performed.
Did you use aftermarket, used spare part?
1. DCDC
DCDC HVIL connectors
X040
X041
There might not be continuity between pin 8 and pin 9 on the DC-to-DC converter. Make sure there is continuity between pins 8 and 9.
2. HV Junction Box
One of reason could be connection in Front Junction Box.
Action to do - check all the connections on and in the front junction box.
HVIL Lid Switch
There is black little button switch. Make sure its connected as described in Service Manual. Link
HVIL lid switch bolt
HVIL lid switch bolt thread is damaged.
X043
Loose HV connector inside Forward Junction Box
X040
- BMS_f036_SW_HVIL
- DI_w086_hvilNotPresent
HVJB lid loose fastener
One of most common reason when a 10mm nut next to one of the two HVIL lid switches is loose.
We had recently one customer who had recently replaced module and replaced charged port. He got an alert after repair. He contacted us, we performed remote diagnosis and provide provide remote support to fix. In this cases, he forgot to tighten some bolts for High Voltage Junction box.
3. Charger
X042
X043
4. Drive Unit
X250 on the drive unit inverter
X250 is damged
Corrosion/moisture inside inverter enclosure.
X976
X939
Please check more details about Drive Unit in another guide. Link
5. HV Battery
X035
Water Ingress
BMS PCBA
X976
Water ingress on the bottom of the ancillary bay
Water ingress on the BMS
6. Rapid Splitter
X036
There may be damage (bent, broken corrosion etc.) with X036.
Pin drag test
Rapid Splitter connects to Battery, Charger Module, Rear Motor Inverter and Front Junction Box.
7. PTC Heater
PTC HV connector on the DCDC. Link
Please check more details about PTC Heater Repair in another guide. Link
8. A/C Compressor
AC Compressor connector on the forward junction box
9. Coolant Heater
Other Hardware issues
Please send us a screenshot or video of your car service alerts, along with your car model and year.
Describe issue as much as you can etc. We will be happy to provide you remote diagnosis and support to clear alerts.
Due to trade secrets, we can not share certain details here.
Feel free to Contact us or Whats App +49 (0) 15226242038. We will be happy to help you to clear the alerts.
Cost
Cost could vary depend on issue, type of workshop, location. If you are looking for online support or affordable Tesla independent workshop. Please feel to Contact Us or Call/Whats App +49 (0) 15226242038. Please have a look on common repair prices Price List
Repair Estimate
Please feel to Contact Us or Call/Whats App +49 (0) 15226242038. We will be happy to provide you estimate and book an appointment for you in best affordable workshop.
Remote diagnosis and support to clear alert
In case, if you have any question or need any support/help. Please feel to contact us Contact Us or Call/Whats App +49 (0) 15226242038.
Find, compare and Book best affordable workshop to fix alert
If are you looking for best workshop who is expert to fix such issue with good price. You can find and compare hundreds of Tesla independent workshops. Please feel free to contact us. We will be happy to organize an appointment with workshop. Please find best workshop through our Workshop Locator
Book an Appointment to fix Alert
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Book an appointment to fix alert in an affordable Workshop
Buy New/Used Spare Parts
Part price could vary depend on condition (New, Used etc.), OEM or Aftermarket part etc.
If you would like to buy new/used spare parts. Please have a look in our catalog or Contact Us Phone/Whats App +49(0)15226242038
Alert Code
Some of most common possible alert code.
You might have received one of following alert.
- BMS_f036
- BMS_w036
- BMS_f008
- BMS_w008
BMS_f008_HW_HVIL
If car is standby, support, or Charge mode. The alert is reported as Fault. Car opens the contactors or keeps them open.
BMS_w008_HW_HVIL
If car is in Drive. The alert is reported as Warning. Car does not open contactors to prevent loss of drive.
BMS_f008, BMS_w008
This is hardware alert
- BMS_w008_HW_HVIL
- BMS_f008_HW_HVIL
- There is a hardware problem with the high voltage interlock loop (HVIL).
- Inability to charge, drive, or support the low voltage (LV) system.
BMS_w036, BMS_f036
This is software alert
- BMS_w036_SW_HVIL
- BMS_f036_SW_HVIL
- The battery management system (BMS) detects an issue with the high voltage interlock loop (HVIL). The voltage at the HVIL output pin of the BMS is too low (in respect to the number of HVIL nodes the vehicle has) or too close to the HVIL open voltage.
- Inability to charge, drive, or support the low voltage (LV) system
BMS_a036
- BMS_a036_SW_HvpHvilFault
- The battery management system (BMS) has detected that the high voltage interlock loop (HVIL) is shorted with the contactors closed.
Please send us your "Service Alert" Screenshot via Contact or Whats App +49 (0) 15226242038. We will be happy to provide you support to fix/reset alert with affordable prices without going to service center which could save your money and time. We can help you to explain the possible cause, how to diagnose, how to fix/reset/repair etc.
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Frequently Asked Questions (FAQs)
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.
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.
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.
Car not under warranty, salvage, accident, flood, modified cars?
It is highly recommended to perform repair with independent workshop to save money.
Car under warranty?
In case if your car is under warranty. It is recommended to perform certain repair works (HV Components, ADAS etc) with OEM during warranty period. Wear and Tear Part Repair could be done with independent workshop to save money. Please read more details in another guide. Link
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? Did you use used spare parts? Still appearing alert: Please free to Contact Us. We will be happy to provide you online support. Phone/Whats App +49(0)15226242038
Source NHTSA
