Normal Operation

With the ignition switch in the START or RUN position, the Instrument Panel Cluster (IPC) receives a RUN/START voltage input from the Smart Junction Box (SJB). The IPC also receives a networked ignition status from the SJB over the Medium Speed Controller Area Network (MS-CAN) communication bus.

• DTC U300A:62 (Ignition Switch: Signal Compare Failure) - the IPC compares the networked input with the hardwired input and sets DTC U300A:62 in continuous memory and on-demand if a discrepancy is detected.
• DTC U300A:64 (Ignition Switch: Signal Plausibility Failure) - the IPC monitors the messaged START status and sets DTC U300A:64 in continuous memory and on-demand if the IPC detects a START input for 15 seconds. Once the fault condition is detected, the IPC retains limited functionality for 15 seconds then returns to full functionality.

This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• SJB
• IPC