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 B1327: Device Voltage Circuit LowDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | B1327 | B1327 | -- | -- |
Ground | -- | B1327 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Value: 12.60 Volts | |||
B+ | 0.00 Volts | 0.00 Volts | 12.60 Volts |
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Value: 12.60 Volts | |||
B+ | 0.00 Volts | 0.00 Volts | 12.60 Volts |
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Value: 12.60 Volts | |||
B+ | 0.00 Volts | 0.00 Volts | 12.60 Volts |
Circuit/System Description
The control modules on this vehicle monitor system voltage through the battery positive voltage circuits. Damage to components, and incorrect data can occur when the voltage is out of range. The following modules monitor the system voltage, and will set DTC B1327 if the system voltage is low:
| • | BCM |
| • | DRR |
| • | HVAC |
| • | IPC |
| • | Radio |
Conditions for Running the DTC
| • | The ignition switch is not in start. |
| • | When the vehicle exits start, the module will delay checking the voltage for 2 seconds. |
Conditions for Setting the DTC
The battery voltage is less than 9 volts for 1.2 seconds.
Action Taken When the DTC Sets
| • | A serial data message will be sent to notify other modules of low battery voltage. |
| • | The module disables the setting of other DTCs. |
Conditions for Clearing the DTC
| • | The DTC will pass when the voltage is greater than 9.5 volts for 1.2 seconds. |
| • | A history DTC will clear after 50 consecutive ignition cycles, if the condition for the malfunction is no longer present. |
Diagnostic Aids
A low voltage DTC in multiple modules indicates a concern in the charging system.
Reference Information
Schematic Reference
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 Battery or Ignition Voltage Signal parameter. The reading should be between 12.60 and 15.00 volts.
| ⇒ | If not within the specified range, refer to Charging System Test . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connectors at the appropriate module.
- Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the appropriate ground circuit terminals listed below and ground.
- Verify that a test lamp illuminates between the appropriate B+ circuit terminals listed below and ground.
- If all circuits test normal, replace the appropriate module.
| • | Terminal 1 (IPC) |
| • | Terminal 9 (DRR) |
| • | Terminal 17 X1 (BCM) |
| • | Terminal 19 X1 (BCM) |
| • | Terminal 20 X1 (BCM) |
| • | Terminal 50 X2 (BCM) |
| • | Terminal A X1 (HVAC) |
| • | Terminal A12 X1 (Radio) |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| • | Terminal 12 (IPC) |
| • | Terminal 16 (DRR) |
| • | Terminal 46 X1 (BCM) |
| • | Terminal 50 X1 (BCM) |
| • | Terminal 51 X1 (BCM) |
| • | Terminal 52 X1 (BCM) |
| • | Terminal 49 X2 (BCM) |
| • | Terminal D X1 (HVAC) |
| • | Terminal B1 X1 (Radio) |
| ⇒ | 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 the appropriate module replacement, setup, and programming.
