2026-03-18

Low Internal Isolation Diagnostics - HV System (Long Range) (Test)

Correction code 44500300700 1.08 NOTE: Unless otherwise explicitly stated in the procedure, the correction code and FRT listed above reflect all of the work required to perform this procedure, including the linked procedures. Do not stack correction codes unless explicitly told to do so. NOTE: See Flat Rate Times to learn more about FRTs and how they are created. NOTE: See Personal Protection to make sure you are wearing proper PPE when performing the procedure below. NOTE: See Ergonomic Precautions for safe and healthy working practices.

Warning

This procedure is a DRAFT. Although it has been validated, Warnings and Cautions might be missing. Follow safety requirements and use extreme caution when working on or near High Voltage systems and components.

2025-12-30: Released new procedure.

Prepare for HV battery removal

Note
Due to the potential issues associated with an isolation fault, customer and/or insurance approval is not needed to remove the HV battery while investigating the fault, For high voltage battery packs that have a low internal isolation condition and/or liquid ingress, It is crucial to remove the fluid promptly, HV gloves, Leather over-gloves, Safety glasses, And safety shoes must be worn at all times while handling a vehicle and/or HV battery pack with an internal isolation condition, Refer to Toolbox article 7410000
Inspect HV insulating gloves

Note
Check gloves for damage prior to use, Refer to service document TN-15-92-003, for information on inspecting HV gloves.
Put on HV insulating gloves and leather over gloves

Note
Use HV cut resistant insulated gloves or HV insulating gloves and leather over gloves, HV Insulating gloves must be worn any time a Hioki Tester or Hi-Pot Tester is used, Refer to service document TN-15-92-003 R5 for PPE requirements depending on vehicle configuration.
Secure vehicle outside of workshop

Note
Secure vehicle in an outdoor area with 15M of space around it in every direction
Open tailgate

Note
Press button to release, Use manual release as necessary
Power off vehicle from center display

Note
Verify EPBs are engaged, Select charge port icon to ensure drive state is disengaged then power down vehicle via Controls > Safety > Power Off
Disconnect first responder loop and MV battery connector

Note
2x connectors, Release locking tab then disconnect FRL connector, Slide eCPA to left then lift lever to release MV battery connector, Early production trucks may have black FRL connector, Release eCPA by pushing down to unlock and slide red locking tab, Wait 2 minutes for electrical circuits to discharge before disconnecting modules
Remove fastener covers from bed floor assembly

Note
14x covers
Remove bed floor assembly

Note
10x short bolts, 15mm, 56 Nm, 2x long bolts, 15mm, 46Nm, Lift front edge with trim tool then remove panel, Recommend assistance
Disconnect ancillary bay MV connector

Note
1x connector, Double locking, Release tab then pivot lever, Release second tab to disengage connector, Wait 1 second between locking tab release to discharge and prevent arcing
Connect breakout harness to ancillary bay MV connector

Note
1x connector
Read HV battery vitals

Note
Refer to Toolbox article 41977, The HV vitals are not stable if any of the following is true:Module temperatures are significantly higher than ambient temperature.Module temperatures min and max deviate from each other more than 5 degrees C.Brick voltages min and max deviate more than 20 mV.If vitals are not stable, isolate the pack or vehicle in 30 meter bubble.
Disconnect breakout harness from ancillary bay MV connector

Note
1x connector, Double locking, Release tab then pivot lever, Release second tab to disengage connector
Prepare work area

Note
Prepare a workspace around a two post lift with nearby access to HV PPE, Battery table, and necessary tooling
Remove rocker covers

Note
Refer to removal steps in HV battery RR procedure
Move vehicle onto lift

Note
Ensure positioning allows rear doors to open, NOTE: If burning odors, popping sounds, flames, or smoke is seen at any time, halt this process and call the fire department immediately! Begin evacuation if vehicle is in the shop.
Raise vehicle fully and lower lift onto locks

Note
Set vehicle to comfortable working height, Ensure an audible click of locks on both sides is heard before lowering, Vehicle may tilt to the side if both locks are not engaged
Remove HV battery pyro disconnects

Note
2x pyro disconnects, Refer to pyro disconnect removal steps in battery RR procedure.
Inspect HV battery flood ports

Note
If any flood port is found open then replace HV battery
Inspect HV battery for dents, fluid leaks, or other signs of instability

Note
If found, refer to Toolbox Article: 7396600
Inspect HV battery for coolant leaks or moisture ingress

Note
Refer to Toolbox article 7410000, If liquid ingress is found then proceed to HV battery removal, If HV battery removal is not possible continue procedure with pack in vehicle
Remove HV battery flood ports

Note
6x flood ports, 8x tabs per flood port, Rotate as needed so that the relief is accessible, Pry between the enclosure and flood port, Once loose remove flood port through relief near breathers
Remove thermal vent

Note
2x tabs, Discard vent and breather after removal
Remove vehicle from lift

Note
Lower rack arms fully and remove them from under vehicle, Remove air suspension from "Jack Mode"
Remove HV battery from vehicle

Note
Refer to HV battery removal procedure for applicable vehicle model
Move HV battery to a suitable work area

Note
Hv battery must have 15M of space around it in every direction
Ensure entire work area is clear

Note
Including above and below battery
Place HV Danger placard on top of battery
Place barricades around work area

Note
Note location of extinguishers and HV rescue hook
Remove HV insulating gloves

Cybertruck Service Manual

Low Internal Isolation Diagnostics - HV System (Long Range) (Test)

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