1) Disconnect the connectors from VDCCM.
2) Run the engine at idle.
3) Measure the voltage between VDCCM connector and chassis ground.
Connector & terminal
(B310) No. 28 (+) — Chassis ground (−):
Is the voltage 10 — 15 V?
Repair the harness connectors between the battery, ignition switch and VDCCM.