A STEP-BY-STEP FRAMEWORK FOR SAFELY DISABLING AND RE-ENABLING HIGH-VOLTAGE SYSTEMS — ALIGNED WITH I-CAR BEST-PRACTICE PRINCIPLES AND COMMON OEM PROCEDURES
As battery-electric and hybrid vehicles become more common in collision repair, safely disabling and re-energizing highvoltage systems is an increasingly important skill for technicians to develop. With the right training and a consistent approach, this work is very manageable.
I-CAR has developed comprehensive training and best-practice guidance on EV high-voltage safety, and technicians are strongly encouraged to consult I-CAR’s EV programs and complete the relevant certifications before performing this type of work [1]. The workflow below is intended as a general reference aligned with those I-CAR principles and common OEM procedures.
Procedures vary between manufacturers and model years, so always retrieve and follow the exact OEM service information for the specific VIN being repaired [2].
BEFORE YOU BEGIN
Technicians are strongly encouraged to consult I-CAR’s EV training resources and complete relevant certifications before performing high-voltage work. This playbook is a general reference only and does not replace I-CAR training, certification, or OEM service information.
“That’s where training and awareness comes in. We need to have the information, and you can learn through online programs, in-person training, et cetera.”
— David Giles, President, Powered EV Consulting Collision Repair Magazine, EV Repair Tour, August 2023
PART 1: DISABLING THE HIGH-VOLTAGE SYSTEM
STEP 1
IDENTIFY THE VEHICLE AND HIGHVOLTAGE ARCHITECTURE
Before beginning any work, it helps to understand the specific high-voltage architecture of the vehicle in front of you. BEVs, PHEVs, and standard HEVs each have different system layouts, and configurations can also vary by model year and trim.
Using the VIN, confirm the following from OEM service information:
• Vehicle type: BEV, PHEV, or HEV
• Nominal system voltage (commonly 400V or 800V)
• Location of the high-voltage battery pack
• Location of the service disconnect
• Number of high-voltage loops in the system
Visual inspection alone is not sufficient. VIN-based OEM research is recommended before proceeding with any high-voltage work.
“Not staying up-to-date on OEM information isn’t an option, and checking in with OEM data isn’t something that collision repair centres do once in a while.”
— Ben Hart, Autobody Technician Instructor, Southern Alberta Institute of Technology (SAIT)
Collision Repair Magazine, EV Repair Tour Calgary, 2023
STEP 2
RETRIEVE AND REVIEW THE OEM DISABLE PROCEDURE
The manufacturer’s high-voltage shutdown procedure — available in the service manual or emergency response guide for the specific VIN — should be reviewed in full before beginning any disable steps. I-CAR guidance is designed to complement OEM procedures, not substitute for them [1].
When reviewing the OEM procedure, look for:
• The required sequence for 12V battery disconnect
• How to locate and remove the service disconnect
• Required capacitor discharge time after disconnect
• Any mandatory wait intervals between steps
• Which points to use for voltage verification
STEP 3
SET UP PPE AND A CONTROLLED WORK ZONE
Appropriate personal protective equipment and a well-organized work area are important foundations for high-voltage work. Before approaching the vehicle, it is recommended to:
• Inspect high-voltage insulated gloves for cuts, cracks, or punctures, and verify the certification date is current
• Wear leather protectors over the insulated gloves
• Remove metallic jewelry such as rings, watches, and bracelets
• Establish a restricted access area around the vehicle
• Post high-voltage warning signage at the perimeter of the work area
“Welding gloves are not appropriate PPE. Nitrile gloves are not high-voltage safety gloves. You need Class 0 gloves — these are the gloves you need whenever you are working with an active EV. They’re your last line of defense.”
— Dirk Fuchs, Director of Technical Programs & Services, I-CAR
FenderBender / Vehicle Service Pros, “Powering Up Safety Basics: EV Repair”
STEP 4
PREVENT UNINTENDED SYSTEM WAKE-UP
Power the vehicle down completely, then move the key fob away from the vehicle. A separate room or a signal-blocking pouch works well for this purpose.
Many EVs are designed to automatically re-engage high-voltage contactors when a key fob is detected nearby. Accounting for key fob location is a simple step that can prevent unintended re-energization during the repair process.
It is also worth confirming the vehicle is not connected to a charging station, as a charging connection will re-energize high-voltage components.
STEP 5
DISCONNECT THE LOW-VOLTAGE (12V) BATTERY
Most OEM procedures call for disconnecting the 12V battery before touching anything else. This step prevents the vehicle’s control systems from commanding the high-voltage contactors to close — which would allow the high-voltage system to re-energize.
Follow the OEM-specified sequence and observe any required wait times before moving to the next step.
“I like to take that extra step of safety precaution — some OEMs only ask you to remove the negative, but disconnecting both terminals gives you another layer of confidence.”
— Jeff Poole, Lead Subject Matter Expert, I-CAR
Repairer Driven News, “I-CAR: Take care to fully disconnect electric vehicles,” June 2021
STEP 6
REMOVE THE HIGH-VOLTAGE SERVICE DISCONNECT
The service disconnect is a manual switch that physically breaks the high-voltage circuit. Its location varies by vehicle — common locations include under a rear seat, in the cargo area, or integrated into the battery housing.
Follow the OEM’s exact removal procedure. Many disconnects include a locking mechanism or require a specific motion before they can be removed.
Once removed, it is good practice to:
• Store the disconnect in a secure location away from the vehicle
• Attach a tag or label to the vehicle indicating it has been high-voltage disabled
STEP 7
WAIT FOR CAPACITORS TO DISCHARGE
After removing the service disconnect, wait the full OEM-specified time before probing any high-voltage points. This interval allows capacitors within the inverter, converter, and other components to discharge to a safe level.
The OEM-specified wait time should not be shortened. Capacitors in EV power electronics can retain significant stored energy after the disconnect is removed, and the discharge interval exists specifically to address that.
“The discharge time is really a serious thing. If the automaker says wait 10 minutes, we have to follow those 10 minutes. The capacitors’ charge can still electrocute a repairer.”
— Dirk Fuchs, Director of Technical Programs & Services, I-CAR
Repairer Driven News, “I-CAR: Take care to fully disconnect electric vehicles,” June 2021
STEP 8
VERIFY ZERO VOLTAGE
Removal of the service disconnect alone does not confirm the system is safe to work near. Voltage verification with a properly rated multimeter is a necessary step. I-CAR guidance consistently emphasizes this verification [1].
A recommended sequence:
• Prove the meter is working by testing it on a known live source
• Probe the OEM-specified high-voltage measurement points
• Confirm zero potential at all required locations
• Re-test the meter on the known live source to confirm it is still functioning
Testing the meter before and after the measurement confirms the reading is valid, not the result of meter malfunction.
STEP 9
APPLY LOCKOUT/TAGOUT AND DOCUMENT
With voltage confirmed at zero, applying a lockout/tagout indicator to the vehicle helps prevent anyone else from inadvertently re-energizing it. Documenting the disable process is also recommended, including:
• Technician name
• Date and time of disable
• Voltage verification method and results
Clear documentation supports consistent, auditable processes and helps protect both the technician and the shop [1].
“You also have to make sure that all of that energy has discharged on the motor side as well before you service something — not just the battery.” — Baily Soto, Legacy EV
PART 2: RE-ENABLING THE HIGH-VOLTAGE SYSTEM
Re-energizing the high-voltage system is its own procedure with its own verification requirements. OEM instructions should be followed carefully and steps should not be skipped.
STEP 10
REINSTALL THE SERVICE DISCONNECT
Before reinstalling, inspect the service disconnect for any signs of damage or contamination. Then seat and lock it fully according to the manufacturer’s instructions.
An improperly seated disconnect may trigger high-voltage interlock fault codes or create an intermittent connection. Taking a moment to confirm full seating can prevent additional diagnostic steps later.
STEP 11
RECONNECT THE 12V BATTERY
Reconnect the 12V battery in the OEM-specified sequence and confirm that terminals are secure. Some vehicles require a specific initialization or wake-up sequence after 12V battery reconnection — check the service information for the specific vehicle.
STEP 12
POWER UP AND PERFORM A FULL SYSTEM SCAN
Turn the vehicle on and conduct a complete diagnostic scan.
Pay particular attention to:
• High-voltage interlock codes
• Isolation fault codes
• Battery management system (BMS) faults
It is generally recommended to investigate and understand any fault codes before clearing them, rather than clearing and re-scanning without first addressing the underlying cause.
“A qualified EV technician is someone who understands the risks involved, has the correct PPE, has done their research, and understands the codes.”
— Cecile Bukmeier, Chair, Auto Body Program, Northern Alberta Institute of Technology (NAIT)
Collision Repair Magazine, EV Repair Tour Calgary, October 2023
A NOTE ON TRAINING
High-voltage disable and re-enable work benefits greatly from proper training and hands-on practice. I-CAR offers EV-specific courses and certifications that provide technicians with the knowledge and confidence to approach this work safely and consistently [1]. Shops and technicians newer to EV repair are encouraged to explore those resources as a starting point.
As EV volume grows across the industry, having a consistent, well-documented process in place helps protect both technicians and the vehicles they repair. This playbook is offered as one reference point in support of that goal — but the OEM service information for the specific vehicle, and the training behind the technician, are what make the difference [1][2].
collisionrepairmag.com/ 15732405
This playbook reflects I-CAR best-practice principles and is intended as a general reference framework. Technicians are encouraged to consult I-CAR training resources and always follow the exact OEM service information for the specific VIN being repaired.
REFERENCES
The following resources informed the development of this playbook and are recommended for further reading and formal training.
[1] I-CAR (Inter-Industry Conference on Auto Collision Repair). Electric Vehicle (EV) Training Programs and Best-Practice Guidance. Available at: www.i-car.com.
[2] Original Equipment Manufacturer (OEM) Service Information. Vehicle-specific high-voltage disable and re-enable procedures should always be obtained from the manufacturer’s service manual or emergency response guide for the VIN being repaired.
[3] National Highway Traffic Safety Administration (NHTSA). Emergency Response Guides for Electric and Hybrid Vehicles. Available at: www.nhtsa.gov.
[4] SAE International. SAE J2578 and related standards covering high-voltage safety in electrified vehicles. Available at: www.sae.org.
[5] Occupational Safety and Health Administration (OSHA). Lockout/Tagout standard (29 CFR 1910.147) and electrical safety regulations. Available at: www.osha.gov.
[6] Giles, D. (2023, August). Quoted in: “Safety First: Don’t sweat battery repair; focus on high voltage safety.” Collision Repair Magazine. Retrieved from collisionrepairmag.com.
[7] Hart, B. (2023). Quoted in: “Adopting a Different (Power)train of Thought.” Collision Repair Magazine, EV Repair Tour Calgary. Retrieved from collisionrepairmag.com.
[8] Bukmeier, C. (2023, October). Quoted in: “Not Just Panel Beaters Anymore.” Collision Repair Magazine, EV Repair Tour Calgary. Retrieved from collisionrepairmag.com.
[9] Fuchs, D. and Poole, J. (2021, June). Quoted in: “I-CAR: Take care to fully disconnect electric vehicles before collision repair.” Repairer Driven News. Retrieved from repairerdrivennews.com.
[10] Fuchs, D. (Various). “Powering Up Safety Basics: EV Repair.” FenderBender / Vehicle Service Pros. Retrieved from vehicleservicepros.com.
[11] Soto, B. (2024, December). Quoted in: “EV Collision Repair Calls for Specialized PPE, Safety Protocols.” Autobody News. Retrieved from autobodynews.com.
This document was prepared as a general educational reference. It does not constitute professional engineering or safety advice. Always follow applicable regulations, manufacturer instructions, and guidance from qualified training organizations.
