RSSI too low in cabinet

How it presents

Symptom

RSSI too low in metal cabinet — antenna placement/routing before modem RMA. Field techs should correlate HMI/Cloud timestamps with RSSI ok ≠ stable websocket — check MTU, NAT, and keepalives.

Root causes (by observed frequency)

1. #1 Primary field cause for MDM-RSSI (RSSI too low in cabinet) on Sierra Wireless

   RSSI ok ≠ stable websocket — check MTU, NAT, and keepalives.

2. #2 Secondary installation or harness issue exposed under load or weather
3. #3 Config/firmware drift after update or board/SIM swap
4. #4 True OEM module failure after cable/site/config paths are proven

Diagnostic procedure

1. 1. Capture Sierra Wireless HMI/Cloud message for MDM-RSSI, connector ID, and last good session

   Expected: Exact string + scope

   Tools: phone, CSMS

2. 2. Correlate logs; decide one gun vs cabinet vs site for “RSSI too low in cabinet”

   Expected: Fault boundary

   Tools: CSMS/OEM cloud

3. 3. Run the rank-appropriate field checks for MDM-RSSI (cable/PE/network/cooling as applicable)

   Expected: Cause supported or excluded

   Tools: DMM, IR, known-good

4. 4. Known-good cable/gun/stall prove when the failure mode allows

   Expected: Follows asset

   Tools: known-good

5. 5. Escalate Sierra Wireless OEM with evidence pack — RSSI ok ≠ stable websocket — check MTU, NAT, and keepalives.

   Tools: ticket

The fix

Resolve MDM-RSSI on Sierra Wireless by ranked field cause (RSSI ok ≠ stable websocket — check MTU, NAT, and keepalives.), then validate a full session.

• Suspect Sierra Wireless assembly for MDM-RSSI

  OEM channel; keep serials

1. Stabilize and document MDM-RSSI presentation before replacing modules.
2. Correct the ranked field cause for RSSI too low in cabinet; prefer cable/site/config fixes first.
3. Clear latches in HMI/CSMS only after the cause is removed.
4. Run authorize → handshake → ≥5 minutes energy → clean stop validation.
5. File scrubbed photos, firmware, and readings with the confirmation.