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 1 CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | B1390 | B1390 | -- | -- |
Ground | -- | B1390 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Range: 12.6 Volts | |||
B+ | 0.0 Volts | 0.0 Volts | -- |
Ground | -- | 0.0 Volts | -- |
Circuit/System Description
The generator battery control module (GBCM) monitors the battery voltage for precision electrical power management. The GBCM monitors both the battery sense positive voltage circuit and the battery sense negative, or ground, circuit to precisely determine system voltage. If there is a difference between the less precise battery voltage circuit and the more precise battery sense circuit of 1 volt or greater for 10 seconds, then DTC B1390 will set.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | This diagnostic runs every 100 ms. |
Conditions for Setting the DTC
The difference between the low precision battery voltage circuit reading and the high precision battery voltage sense circuit reading is greater than or equal to 1 volt for 10 seconds.
Action Taken When the DTC Sets
| • | The driver information center (DIC) displays the BATTERY message. |
| • | The GBCM uses the less accurate battery positive voltage circuit for voltage readings. |
Conditions for Clearing the DTC
This DTC will pass when the difference between the less precision battery positive voltage circuit reading and the high precision battery voltage sense circuit reading is less than 1 volt.
Diagnostic Aids
| • | You must cycle the ignition after clearing the DTC to turn off the BATTERY DIC message. |
| • | Overcharging with a battery charger or jump starting could cause this DTC to set. |
| • | A high voltage value in multiple modules indicates a concern in the charging system. |
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Description and Operation
Charging System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 volts.
- Observe the scan tool GBCM Battery Voltage Signal parameter. The reading should be between 12.6 and 15.0 volts.
| ⇒ | If not within the specified range, refer to Charging System Test . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the GBCM.
- Ignition OFF, scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the following ground circuit terminals and ground:
- Ignition ON, verify that a test lamp illuminates between the following B+ circuits and ground:
- If all circuits test normal, replace the GBCM.
| • | Terminal F |
| • | Terminal H |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| • | Terminal A |
| • | Terminal C |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for GBCM replacement, setup and programming.
