P0A95: The battery controller infers a fuse problem from voltage difference

SAIC's BMS chapter calls P0A95:00 a broken pack main fuse. The detection is more informative than that title: with the main relay closed and battery voltage normal, the controller detects more than ten volts difference across the fuse for five seconds.

A measured difference is the evidence

The BMS obtains the relevant information through high-voltage sampling connections in the electric power distribution module. The source also lists harness or connector faults and BMS/EDM problems as possible causes. A recorded fuse code therefore does not eliminate the measurement path from diagnosis.

The recovery criterion is a difference below ten volts for one second. This is distinct from the five-second fault confirmation, and history has its own 40-failure-free-cycle rule. None of those status rules is a reason to continue operating a faulty high-voltage system until memory clears.

This is professional high-voltage work

The factory diagnostic procedure requires the full battery service and isolation process before internal checks. This overview intentionally does not reproduce pack-opening, isolation or probing instructions. A qualified high-voltage technician must distinguish a genuine fuse discontinuity from a sampling or control problem using the applicable procedure.

The code does not justify bridging the fuse, fitting a different rating or replacing the entire battery without further evidence. Retain the full :00 record and related battery faults so the supported repair addresses the cause of the measured voltage difference.

This interpretation is limited to the cited MG4 UK manual revision; it does not establish applicability to every MG4 build or another manufacturer.

Source: SAIC Motor MG4 UK Guided Fault Finding DTC Support v1.02.