Insulation or high-voltage warning

The dash shows an insulation, isolation, HV or leakage warning. On most electric vehicles, the high-voltage battery circuit is kept fully separate from the frame. An insulation monitor checks this all the time. A warning means it has found a leak path from the high-voltage circuit to the frame. Causes include water or condensation, battery leakage, frayed or crushed cables, crash damage, faulty connectors and conductive dirt (Power Systems Design). Even a single fault can be a shock hazard (Power Systems Design). Not every small electric bike has this monitor; if yours shows this warning, take it seriously.

Is it safe to ride?

Stop now. Park safely, switch off and do not charge. Do not touch bare metal parts near the battery, motor or controller.

Quick checks first

• Is there smoke, heat, hissing or a chemical smell from the battery? If yes, move away and call for help.
• Has the bike been through deep water, a flood, or been pressure-washed?
• Has it fallen or crashed recently?
• Have accessories been wired in recently?

Diagnose it step by step

1Is there smoke, heat, hissing or a chemical smell?

• Yes: move away, keep people away, call the fire service if it smokes. See Battery pack is hot, hissing or smells.
• No: go to step 2.

2Has the bike been in deep water, a flood, or heavy washing?

• Yes: go to Bike has been in deep water or a flood. Do not switch on or charge.
• No: go to step 3.

3Has the bike crashed or fallen, or is any orange or thick cable visibly damaged?

• Yes: treat the battery as possibly damaged: Battery pack is dropped, dented, swollen or wet.
• No: go to step 4.

4Did the warning appear only while charging?

• Yes: unplug at the wall. The charger, its cable or the charge port may be the leak path. Do not use that charger again until tested. Try nothing else; go to step 5.
• No: go to step 5.

5. Record the warning and call for recovery. Read electric drive error codes. Call the dealer, fleet or swap operator support line. Ask for the bike to be collected, not ridden in.

6. Workshop: the technician isolates the HV system (Make an electric motorcycle safe to work on) and tests each part to find the leak: Check high-voltage insulation. The test voltage and pass value come from the manufacturer only. Training in first response does not make someone competent to repair HV parts (IMI EV02).

What happens if you keep riding: the leak can get worse with vibration and water, and a second fault can make the frame live.

Causes, most likely first