B1390

DTC B1390

Diagnostic Instructions

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

DTC Descriptor
DTC B1390
- Device Voltage Reference Input Circuit

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) has an internal precision battery voltage sensor connected to dedicated battery positive voltage from X1 terminal 51 and dedicated ground terminal 19. The BCM then compares the sensors voltage to the battery positive voltage from X1 terminal 52. DTC B 1390 will set if these voltages are different by greater than 2 volts.

Conditions for Running the DTC

This DTC will run only if the BCM has power and ground. This DTC will execute regardless of the source voltage.

Conditions for Setting the DTC

This code shall be set when the 2 battery positive voltages differ by 2 volts or greater for more than 10 seconds.

Action Taken When the DTC Sets

All writes to the electrically erasable programmable read only memory (EEPROM) will be suspended. All loss of communication and low/high voltage DTC codes are suspended.

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.

Reference Information
Schematic Reference

Body Control System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Body Control System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for Scan Tool Information

Circuit/System Testing

1. Ignition OFF, disconnect the X-1 harness connector at the BCM.
2. Verify that there is less than a 2 volt difference between the battery positive voltage circuit terminal 51 and the ground circuit terminal 19, and between the battery positive voltage circuit terminal 52 and the ground circuit terminal 17.

• If greater than the specified range, test the voltage circuits for a short to ground or open/high resistance, and the ground circuits for open/high resistance.

3. If the circuits test normal, replace the BCM.

Repair Instructions

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

Refer to Control Module References (Programming and Relearning) for module replacement, setup, and programming