Circuit Description
The body control module (BCM) has an internal battery voltage sensor and a reference voltage. The BCM compares these 2 voltages via the 2 battery positive voltage circuits every 300 milliseconds.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1390 Device Voltage Reference Input {single or 1} Circuit
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 after 10 consecutive readings that the 2 battery positive voltages differ by one volt or greater.
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. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Body Control System Schematics Connector End View Reference: Computer/Integrating Systems Connector End Views | ||||
1 | Did you perform Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Is the voltage difference less than the specified value? | 1 V | Go to Step 5 | Go to Step 3 |
3 | Test both BCM battery positive voltage circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 4 |
4 | Test both BCM ground circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 5 |
5 | Inspect for poor connections and terminal tension at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 6 |
6 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
