Pinpoint Tests AU: DTC B2A20 Or U2472
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AU: DTC B2A20 Or U2472
Normal Operation
The Instrument Cluster (IC) receives both the RUN/START and keep alive voltage from the Smart Junction Box (SJB).
- DTC U2472 Unexpected Ignition State - a continuous memory DTC that sets in the IC when it detects a discrepancy between the hardwired voltage input and the messaged ignition state inputs from the SJB for greater than 5 seconds when the ignition switch is in the RUN position.
- DTC B2A20 Ignition Stuck in START - a continuous memory DTC that sets in the IC if the ignition START message sent from the SJB is stuck in the START position for greater than 15 seconds.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- SJB
- IC
PINPOINT TEST AU: DTC B2A20 OR 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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AU1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check for recorded IC DTCs from the self-test.
- Is DTC B2A20 recorded?
Yes
GO to AU2.
No
For DTC U2472, GO to AU2.
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AU2 CHECK THE IC RUN/START VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: IC C220.
- Measure the voltage between the IC C220-20, circuit CBP29 (WH/VT), harness side and ground.
- Ignition ON.
- Measure the voltage between the IC C220-20, circuit CBP29 (WH/VT), harness side and ground.
- Place the key in the START position.
- Measure the voltage between the IC C220-20, 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
GO to AU3.
No
VERIFY the SJB fuse 29 (5A) is OK. If OK, REPAIR the circuit in question. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number
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AU3 CHECK THE SJB INPUT PIDs FROM THE IGNITION SWITCH
- 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 AU4.
No
REFER to Steering Column Switches Testing and Inspection to diagnose the ignition switch outputs to the SJB.
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AU4 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 DTC U2472 still present?
Yes
GO to AU5.
No
The system is operating correctly at this time. The DTC may have been set due to high network traffic.
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AU5 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. REFER to Multifunction Electronic Modules Service and Repair. TEST the system for normal operation.
If the concern remains, REINSTALL the original SJB and GO to AU6.
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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AU6 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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