Pinpoint Tests AQ: DTC B1557

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test AQ: DTC B1557

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

Normal Operation
- DTC B1557 (Ignition RUN/START Circuit Short to Battery) - a continuous DTC that sets in the Instrument Cluster (IC) if the IC receives a voltage input on circuit 489 (PK/BK) and a message from the Smart Junction Box (SJB) indicating that the ignition switch has transitioned to the OFF or ACC position.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- SJB
- IC



PINPOINT TEST AQ: DTC B1557

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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AQ1 CHECK THE IC VOLTAGE SUPPLY


- Ignition OFF.
- Disconnect: IC C220.
- Measure the voltage between the IC C220-26, circuit 489 (PK/BK), harness side and ground.




- Is any voltage present?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

No
GO to AQ2.

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AQ2 CHECK THE SJB IGNITION SWITCH PIDs


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB ignition switch (IGN_SW) PID while moving the ignition switch from the RUN/START position to the OFF and ACC positions.
- Does the PID agree with the ignition switch position?

Yes
GO to AQ3.

No
VERIFY that all SJB controlled systems function correctly. INSTALL a new SJB. TEST the system for normal operation.

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AQ3 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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