Pinpoint Tests AD: DTC B2A20 Or U2472

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test AD: DTC B2A20 or U2472

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 Cluster (IC) receives voltage from the Smart Junction Box (SJB) through circuit CBP29 (WH/VT). With the ignition switch in the OFF position, the IC receives its keep-alive voltage from the SJB through circuit SBP26 (YE/RD). The IC also monitors the ignition switch position data received from the SJB over the MS-CAN communication bus.

- DTC B2A20 (Ignition Stuck in START) - a continuous memory DTC that sets in the IC when the IC detects the SJB messaged ignition state in start for greater than 15 seconds.
- DTC U2472 (Unexpected Ignition State) - a continuous and on-demand DTC that sets in the IC when the cluster 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(s)
- Wiring, terminals or connectors
- IC



PINPOINT TEST AD: DTC B2A20 OR DTC U2472

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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AD1 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND IC SELF-TESTS


- Check for recorded IC DTCs from the continuous and on-demand self-tests.
- Is DTC B2A20 recorded?

Yes
GO to AD3.

No
GO to AD2.

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AD2 CHECK THE IC RUN/START VOLTAGE SUPPLY


- Ignition OFF.
- Disconnect: IC C220.
- Ignition ON.
- Measure the voltage between the IC C220-14, circuit CBP29 (WH/VT), harness side and ground.




- Ignition OFF.
- Remove the PCM power relay.
- Place the ignition in the START position.
- Measure the voltage between the IC C220-14, circuit CBP29 (WH/VT), 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
REINSTALL the PCM power relay. GO to AD3.

No
REINSTALL the PCM power relay. VERIFY the SJB fuse 29 (5A) is OK. If OK, REPAIR the circuit. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.

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AD3 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 ignition switch ACC (IGN_A_ECU), ignition switch OFF (IGN_O_ECU), ignition switch RUN (IGN_R_ECU), and ignition switch START (IGN_S_ECU) PIDs. Monitor the ignition switch PIDs while cycling the ignition switch from ACC, OFF, RUN and START.
- Do the SJB PIDs match the ignition switch position?

Yes
GO to AD4.

No
REFER to Steering Column to diagnose the ignition switch outputs to the SJB. Testing and Inspection

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AD4 CHECK THE IC DTCs


- Enter the following diagnostic mode on the scan tool: IC Self-Test.
- Repeat the IC self-test. Clear the DTCs.
- Is DTC B2A20 or U2472 still present?

Yes
GO to AD5.

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

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AD5 CHECK FOR CORRECT SJB OPERATION


- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify that the concern is still present.
- Is the concern still present?

Yes
INSTALL a new SJB. TEST the system for normal operation.

If the concern remains, REINSTALL the original SJB and GO to AD6.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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AD6 CHECK FOR CORRECT IC OPERATION


- Disconnect the IC connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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