Pinpoint Tests AZ: DTC U300A:94

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests


Pinpoint Test AZ: DTC U300A:94

Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. 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 receives its keep-alive voltage from the 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:94 (Unexpected Ignition State) - a continuous and on-demand DTC that sets in the IPC when the IPC detects a discrepancy between the hardwired voltage input and the messaged ignition state inputs from the SJB. The SJB 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



PINPOINT TEST AZ: 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.

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AZ1 CHECK THE IPC RUN/START VOLTAGE SUPPLY


- Ignition OFF.
- Disconnect: IPC C220.
- Measure the voltage between the IPC C220-3, circuit CBP36 (BU/BN), harness side and ground.




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




- Place the ignition in the START position.
- Measure the voltage between the IPC 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 AZ2.

No
VERIFY the SJB 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 Diagrams By Number.

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AZ2 CHECK THE SJB INPUT PIDs FROM THE IGNITION SWITCH


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Select the SJB 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 PIDs match the ignition switch positions?

Yes
GO to AZ3.

No
REFER to Steering Column to diagnose the ignition outputs to the SJB.

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AZ3 CHECK THE IPC DTCs


- Enter the following diagnostic mode on the scan tool: IPC Self-Test.
- Repeat the IPC self-test. Clear the DTCs.
- Is DTC U300A:94 still present?

Yes
INSTALL a new SJB. REFER to Body Control Systems. 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.

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