Pinpoint Test BA: DTC U300A:94

Instrumentation, Message Center and Warning Chimes

Pinpoint Test BA: DTC U300A:94

Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information [1][2]Diagrams By Number.

Normal Operation

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

- DTC U300A:94 (Ignition Switch: Unexpected Operation)- a continuous and on-demand DTC that sets in the IPC (Instrument Panel Cluster) when the IPC (Instrument Panel Cluster) detects a discrepancy between the hardwired voltage input and the messaged ignition state inputs from the SJB (Smart Junction Box). The SJB (Smart Junction Box) messaged input indicates RUN while the hardwired input indicates RUN/START for more than 5 seconds.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- IPC (Instrument Panel Cluster)

PINPOINT TEST BA : DTC U300A:94

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

BA1 CHECK THE IPC (Instrument Panel Cluster) RUN/START VOLTAGE SUPPLY

- Ignition OFF.

- Disconnect: IPC (Instrument Panel Cluster) C220.

- Measure the voltage between the IPC (Instrument Panel Cluster) C220-3, circuit CBP36 (BU/BN), harness side and ground.





- Ignition ON.

- Measure the voltage between the IPC (Instrument Panel Cluster) C220-3, circuit CBP36 (BU/BN), harness side and ground.





- Place the ignition in the START position.

- Measure the voltage between the IPC (Instrument Panel Cluster) C220-3, circuit CBP36 (BU/BN), harness side and ground.





Is the voltage 0 volts in the OFF position and greater than 10 volts in the RUN and START positions?

Yes
GO to BA2.

No
VERIFY the SJB (Smart Junction Box) fuse 36 (5A) is OK. If OK, REPAIR the circuit for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number.

BA2 CHECK THE SJB (Smart Junction Box) INPUT PIDs FROM THE IGNITION SWITCH

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: SJB (Smart Junction Box) DataLogger.

- Select the SJB (Smart Junction Box) PIDs: ignition ACC (IGN_A_ECU), ignition OFF (IGN_O_ECU), ignition RUN (IGN_R_ECU), and ignition START (IGN_S_ECU). Monitor the ignition PIDs while switching the ignition from ACC, OFF, RUN and START.

Do the SJB (Smart Junction Box) PIDs match the ignition switch positions?

Yes
GO to BA3.

No
REFER to Steering Column to diagnose the ignition outputs to the SJB (Smart Junction Box).

BA3 CHECK THE IPC (Instrument Panel Cluster) DTCs

- Enter the following diagnostic mode on the scan tool: IPC (Instrument Panel Cluster) Self-Test.

- Repeat the IPC (Instrument Panel Cluster) self-test. Clear the DTCs.

Is DTC U300A:94 still present?

Yes
INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.

No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.