Circuit Description
The body control module (BCM) has an internal battery voltage sensor and a reference voltage. The BCM compares 2 of the 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 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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests for the proper voltage at battery positive voltage sense circuits of the BCM. If voltages are not within the proper operating range, the voltage sense circuits needs to be tested.
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This step tests the ground sense circuit of the BCM.
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This step tests for the proper voltage of the battery sense circuits to the BCM. If voltage is not within the proper operating range, the battery positive voltage and ground circuits of the BCM need to be tested.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Starting and Charging Schematics, Body Control System Schematics or Computer/Integrating Systems Connector End Views Connector End View Reference: Master Electrical Component List | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Do any of the voltages differ more than the specified value? | 3 V | Go to Step 5 | Go to Step 3 |
Do the voltages differ more than the specified value? | 3 V | Go to Step 9 | Go to Step 4 | |
Measure the voltage from the B+/IGN voltage circuits of the BCM and a good ground. Do the voltages differ more than the specified value? | 3 V | Go to Step 8 | Go to Step 7 | |
Does the voltage measure within the specified range? | 10.5-15.5 V | Go to Step 9 | Go to Step 6 | |
6 | Measure the voltage between the battery positive voltage circuits of BCM and a good ground. Does the voltage measure within the specified range? | 10.5-15.5 V | Go to Step 8 | Go to Step 7 |
7 | Test the B+/IGN voltage circuits of BCM for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
8 | Test the ground circuit of the BCM for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
9 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 |
10 | Replace the module BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
