GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptor

DTC B1390: Device Voltage Reference Input Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery Positive Voltage (BCM C1-51)

B1390

B1390

--

B1390

Battery Positive Voltage (BCM C1-52)

B1390

B1390

--

B1390

Ground (BCM C1-19)

--

B1390

--

B1390

Ground (BCM C1-17)

--

B1390

--

B1390

Circuit/System Description

The body control module (BCM) has an internal precision battery voltage sensor connected to dedicated battery positive voltage from terminal C1-51 and dedicated ground terminal C1-19. The BCM then compares the sensors voltage to the battery positive voltage from terminal C1-52. 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

Connector End View Reference

Data Communication Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

  1. Ignition OFF, disconnect the C-1 harness connector at the BCM.
  2. Verify that there is less than a 2 volt difference between the battery positive voltage circuit terminal C1-51 and the ground circuit terminal C1-19, and between the battery positive voltage circuit terminal C1-52 and the ground circuit terminal C1-17.
  3. 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.
  4. If the circuits test normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to Control Module References for module replacement, setup, and programming