Cable check isolation fail

How it presents

Display

Cable check isolation fail

Symptom

Cable check isolation fail on protocol: CSMS StatusNotification + connector LEDs shows CCS-H03. Techs see session abort or stall Unavailable until the ranked cause is cleared. Correlate OCPP websocket / SECC / vehicle logs as applicable before opening the cabinet.

Root causes (by observed frequency)

1. #1 Cable or gun insulation breakdown presenting as CCS-H03

   Swap known-good cooled/uncooled cable before condemning power stage

2. #2 Coolant contamination or leak wetting DC bus sensors
3. #3 Y-cap / filter path degraded after surge or grid event

Diagnostic procedure

1. 1. Capture CSMS StatusNotification + connector LEDs message for CCS-H03, connector ID, and last successful session time

   Expected: Exact display string + OCPP status/errorInfo if present

   Tools: phone photos (scrubbed), CSMS

2. 2. Pull OCPP websocket / SECC / vehicle logs as applicable; confirm whether Cable check isolation fail follows one gun, one cabinet, or the whole site

   Expected: Fault correlates to one path

   Tools: CSMS export, OEM cloud

3. 3. On hardware, isolate power quality / protective devices before opening HV for CCS-H03

   Expected: Voltage in band; no unexpected trips

   Tools: DMM, IR gun, LOTO kit

4. 4. Execute rank-1 cause check for “Cable check isolation fail”; swap known-good cable/gun or stall if available

   Expected: Fault moves with cable or stays with cabinet

   Tools: known-good cable, IR, OEM service menu

5. 5. If unresolved, escalate with CCS-H03 evidence pack (HMI photo, OCPP snippet, readings) — Stay OEM-agnostic until the protocol stage pins a hardware path

   Tools: ticket template

The fix

Clear CCS-H03 (Cable check isolation fail) by correcting the ranked cause on protocol, then run a full validation session.

• DC cable / gun assembly

  Match cooled vs uncooled; OEM-approved only

  protocol-cable-std

• Suspect module or controller indicated by rank-1 cause

  OEM protocol service channel; keep serial for RMA

  CCS-H03

1. LOTO and verify zero energy per protocol HV procedure before any bus work
2. Correct rank-1 cause for CCS-H03; do not shotgun-replace modules
3. Clear fault latches in HMI/CSMS; confirm StatusNotification returns to Available/Preparing as appropriate
4. Run validation: authorize → handshake → ≥5 minutes energy → clean stop; capture MeterValues
5. Document firmware, part lots, and scrubbed HMI photos for confirmations