For 1990-2009 cars only
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 | -- | -- |
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. This vehicle has multiple modules that will set this DTC. For more information on which modules, refer to Diagnostic Trouble Code (DTC) List - Vehicle
Conditions for Running the DTC
| • | This DTC shall run only if the module has power, ground, and the ignition is not in START mode. |
| • | This DTC shall execute regardless of the battery voltage. |
Conditions for Setting the DTC
| • | This DTC shall be set as current when the voltage falls below 9 V for 1.2 seconds |
| • | When the vehicle exits START, the module shall delay checking the voltage for 2 seconds. |
Action Taken When the DTC Sets
| • | A serial data message shall be sent out to notify all other modules of low battery voltage. |
| • | The modules disable the setting of U codes and other DTCs. |
Conditions for Clearing the DTC
| • | The DTC will clear current status when the voltage is greater than 9.5 V 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 set in multiple modules indicates a concern in the charging system. |
| • | A low voltage value 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 measure and record the voltage at the battery terminals.The battery voltage is 12.6-15.5 V.
- Observe the appropriate control module scan tool Battery Positive Voltage parameter. The reading should be between 12.6 and 15.5 V.
| ⇒ | If the battery voltage is not within the specified range, refer to Charging System Test |
Circuit/System Testing
- Ignition OFF, disconnect the harness connectors at the appropriate control module.
- Ignition OFF, test for less than 5.0 Ω between the ground circuit(s) and ground.
- Ignition ON, verify a test lamp illuminates between the B+ circuit and ground.
- If the circuit tests normal, replace the appropriate control module.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp did not illuminate , test the B+ circuit(s) 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 control module replacement, setup and programming.
