30/06/2026 10:54 am
Topic starter
Automotive Q&A
Where should a general workshop stop when an EV reports an isolation fault?
Review the evidence, add a focused answer, and distinguish confirmed measurements from assumptions.
Notifications
Clear all
Technician Exchange
2
Posts
2
Users
0
Reactions
199
Views
0
We can scan the vehicle and inspect accessible low-voltage wiring, but technicians need a clear boundary when a DTC reports reduced high-voltage insulation. The temptation is to start disconnecting orange components to see which code changes.
What triage is useful before handing the vehicle to a high-voltage-qualified technician?
1 Answer
0
23/08/2026 1:12 pm
Record the exact DTC, status, freeze frame, recent repair or collision history, weather and charging conditions. Inspect only accessible low-voltage connectors, coolant levels and obvious external damage that the service information identifies as safe with the vehicle intact. Do not disconnect orange connectors, open enclosures or use a conventional ohmmeter on the high-voltage bus.
Isolation testing requires the manufacturer procedure, rated PPE and tools, disabling steps and proof of zero voltage. A useful handoff preserves evidence and identifies when the fault occurs; it does not expand an unqualified technician's work boundary.
Topic starter
24/08/2026 8:34 am
The shop added a red stop point to the triage form. On the first case, the handoff included a freeze frame showing the fault only during DC charging and recent coolant service. The qualified team found the issue without anyone opening high-voltage connectors in the general bay.