Pinpoint Test A: DTC B1555

Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand

Pinpoint Tests

Pinpoint Test A: DTC B1555

Refer to Wiring Diagram Set 34, Four-Wheel Drive System for schematic and connector information. Diagrams By Number

Normal Operation

The 4X4 control module receives ignition switch position status from the hardwired run/start input to 4X4 control module pin 8 and the ignition switch position status message communicated by the Instrument Cluster (IC) over the High Speed Controller Area Network (HS-CAN). The ignition switch position status message originates from the Smart Junction Box (SJB) which communicates the ignition switch position status over the Medium Speed Controller Area Network (MS-CAN) to the IC which acts as a gateway module, transferring the ignition switch status message from MS-CAN to HS-CAN. For information regarding network messaging, refer to Information Bus.

- DTC B1555 Ignition Run/Start Circuit Failure - If the ignition switch is not in RUN for the self-test, this code will set.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Ignition switch and/or circuitry
- HS-CAN



PINPOINT TEST A: B1555

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A1 CARRY OUT NETWORK TEST


- Ignition ON.
- Connect the scan tool.
- Carry out a network test.
- Did the network test pass?

Yes
GO to A2.

No
REFER to Information Bus to diagnose the network concern.

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A2 CHECK 4X4 INDICATOR PROVE-OUT


- Carry out the 4X4 control module self-test.
- Are any 4X4 control module DTCs present?

Yes
For DTC B1555, GO to A3. For all other DTCs, refer to the 4X4 Control Module DTC Chart. Four Wheel Drive (4WD) Systems -1- Speed Torque-on-Demand

No
The system is functioning correctly.

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A3 CHECK THE 4X4 CONTROL MODULE IGNITION SWITCH STATUS PIDs


- Enter the following diagnostic mode on the scan tool: DataLogger - 4X4 Control Module.
- Monitor the following ignition switch PIDs:
- Ignition Switch - Off/Unlock Position (IGN_O/U)
- ACC Position (IGN_A)
- Start Position 3 (IGN_S)
- Ignition Switch - Run/Start Position (IGN_R/S)
- Ignition Switch - Run Position (IGN_R)
- Do the ignition switch PIDs match the ignition switch positions?

Yes
The system is functioning correctly.

No
If the IGN_R/S PID did not match, CHECK SJB fuse 35 (10A). If the fuse is OK, REPAIR circuit CBP35 (YE/GY). CLEAR the DTCs. REPEAT the self-test.

If the IGN_O/U, IGN_A, IGN_S or IGN_R PIDs did not match, REFER to Steering Column to diagnose the ignition switch concern. Testing and Inspection

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