B1433

DTC B1433

Circuit Description

The body control module (BCM) controls the HVAC blower motors through the RUN relay circuit. When the ignition switch is in either the ACC or the ON position, the BCM provides battery negative voltage to the RUN relay control circuit. When the RUN relay is energized, it supplies B+ to the HVAC blower motor switches.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1433 Ignition-Switched Power Relay 2 Circuit

Conditions for Running the DTC

The system voltage must be between 9-16 volts.

Conditions for Setting the DTC

* The BCM detects a short to voltage in the RUN relay control circuit when the BCM is trying to energize the relay.
* The BCM detects that the RUN relay control circuit is open.
* The condition above must be present for more than 1 second.

Action Taken When the DTC Sets

* The BCM stores DTC B1433 in memory.
* The devices powered by the RUN supply voltage circuit will not operate.

Conditions for Clearing the DTC

* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Test Description

Step 1 - Step 11:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the RUN relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. This step tests for voltage at the coil side of the RUN relay.
4. This step verifies that the BCM is providing ground to the RUN relay.
5. This step tests the control circuit side of the RUN relay for faults.
10. After replacement of the BCM you must calibrate the new module for proper operation.