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 Circuit - GBCM RVC VSENSE B+Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
RVC PWR B+ | -- | -- | -- | -- |
RVC VSENSE B+ | B1390 | B1390 | -- | -- |
Ground | -- | B1390 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON Parameter Normal Value: 12.60 V | |||
RVC PWR B+ | 12.60 V | 12.60 V | 12.60 V |
RVC VSENSE B+ | 0.00 V | 0.00 V | 12.60 V |
Circuit/System Description
The generator battery control module (GBCM) monitors the battery voltage for precision electrical power management. The GBCM monitors both the RVC PWR B+ circuit and the RVC VSENSE B+ circuit to precisely determine system voltage. If the RVC VSENSE B+ circuit is 1.5 V less than the RVC PWR B+ circuit for 7 seconds, then DTC B1390 will set.
Conditions for Running the DTC
This diagnostic runs every 100 ms.
Conditions for Setting the DTC
The RVC VSENSE B+ circuit is 1.5 V less than the RVC PWR B+ circuit for 7 seconds
Action Taken When the DTC Sets
| • | The GBCM will request the driver information center (DIC) to display the SERVICE CHARGSYS message. |
| • | The GBCM uses the less accurate RVC PWR B+ circuit for voltage readings. |
Conditions for Clearing the DTC
| • | During the current ignition cycle, the difference between the less precision battery positive voltage circuit reading and the high precision battery voltage sense circuit reading is less than 1.5 V. |
| • | The SERVICE CHARGSYS DIC message will turn off 7 seconds after the voltage on the RVC VSENSE B+ circuit returns to normal. |
Diagnostic Aids
| • | Inspect the RVC PWR and RVC VSENSE fuses for opens. |
| • | Inspect ground G102. Verify that it is clean and tight. |
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 V.
- Observe the scan tool GBCM Battery Voltage Signal parameter. The reading should be between 12.6 and 15.0 V.
| ⇒ | 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, test for less than 6.5 Ω between the ground circuit terminals listed below and ground.
- Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.
- If all circuits tests normal, replace the GBCM.
| • | Terminal H |
| • | Terminal F |
| ⇒ | 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
