Deactivate the Vehicle RESS Quiz - National Skills Portal

Why is the vehicle key/fob kept at least 5 metres from the vehicle during depowering?

To protect the key from magnetic fieldsSmart-entry can wake the vehicle and re-close the HV contactorsIt is required for insurance photosTo stop the radio draining the battery

When disconnecting the 12 V battery, which terminal comes off first and why?

Positive — it is the live oneNegative — a slipped tool then cannot create a short circuit to bodyEither — order is irrelevantBoth together

Removing the Manual Service Disconnect (MSD) typically does what inside the pack?

Discharges all cells to zeroSplits the battery string mid-pack and usually removes the main HV fuseTurns off the BMSVents the coolant

PPE state while pulling the service plug should be:

Bare hands for feelClass 0 gloves (air-tested) with over-protectors, face shield, one-hand techniqueNitrile workshop glovesAny gloves, no shield

After the plug is out, work can begin:

Immediately — the source is removedAfter the OEM capacitor discharge wait AND a prove–test–prove zero-volt verificationAfter washing the vehicleAfter 1 minute

The correct prove–test–prove verification sequence is:

Test bus → prove meterProve meter on live source → test HV bus (all pairs < 5 V) → prove meter againProve once, test twiceVisual inspection only

Which THREE measurements confirm the HV bus is de-energised?

HV+ to HV−, HV+ to chassis, HV− to chassis — all < 5 V DCHV+ to HV− onlyChassis to ground12 V battery voltage

The removed service plug must be:

Left on the workbench for refitKept on your person or locked away, with a danger tag on the vehicleGiven to the customerTaped to the windscreen

During the zero-volt verification itself, the technician:

May remove gloves — the plug is outWears full HV PPE, because the bus is treated as live until the second proveUses bare probes for accuracyStands on wet ground

A reading of 180 V DC appears between HV+ and chassis after the discharge wait. You should:

Proceed — it is under 400 VStop, keep PPE on, re-check isolation steps and the OEM procedure; do not touch until < 5 VShort it to chassis to dischargeWait one more minute and touch

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