B1448

DTC B1448

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1448 00
- Accessory Power Relay Circuit

Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) controls the wired accessory power components by applying voltage to the ignition voltage circuit at harness connector X5 terminal 14. Voltage is applied when the ignition switch is in ACC or ON.

Conditions for Running the DTC

* The system voltage is between 9-16 volts.
* The DTC can only set when the output is actively being requested by the module. Refer to Circuit/System Description for specific conditions.

Conditions for Setting the DTC

The DTC will set only when the module requests the output and there is a short to ground in the ignition voltage circuit.

Action Taken When the DTC Sets

The module output driver will be shut down and not supply voltage to the circuit.

Conditions for Clearing the DTC

* The current DTC will clear when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Circuit/System Testing

1. Ignition ON, verify DTC B1448 is set as current.

^ If DTC B1448 is not set as current, operate the vehicle within the Conditions for Setting the DTC.

Important: When cycling the ignition, keep ignition OFF for 5 seconds before checking for current DTC.

2. Disconnect each of the following components one at a time. The components may be disconnected in any order. After each component is disconnected, cycle the ignition and verify DTC B1448 remains set as current.

* Outside moisture sensor (with RPO CE1)
* Transfer case shift select switch (with RPO NQF/NQH)

^ If DTC B1448 does not remain set as current, test or replace the last component that was disconnected.

3. With all components disconnected, cycle the ignition and verify DTC B1480 is not set as current.

^ If DTC B1448 remains set as current, test the ignition voltage circuit at any disconnected component for a short to ground. If the circuit tests normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Transfer Case Shift Control Switch Replacement (Without SLT) Transfer Case Shift Control Switch Replacement (With SLT)
* Windshield Outside Moisture Sensor Replacement