Circuit Description
The control modules on this vehicle monitor the battery voltage through the battery positive voltage circuits.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1325 Device Power 1 Circuit
This vehicle has DTCs that include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description .
DTC Symptom | DTC Symptom Descriptor |
|---|---|
03 | Voltage Below Threshold |
07 | Voltage Above Threshold |
Conditions for Running the DTC
The voltage supplied to the control modules is in the range of 7-26 volts.
Conditions for Setting the DTC
B1325 03
The control module detects a system voltage below 9 volts and the condition is present at least 5 seconds.
B1325 07
The control module detects a system voltage above 18 volts and the condition is present at least 5 seconds.
Action Taken When the DTC Sets
| • | The control module immediately disables all outputs when a high voltage condition is detected, with the exception of GMLAN and Crank relay that are disabled after a 3 minute delay. |
| • | The setting of other DTCs is inhibited. |
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. |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Control Module References | ||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
2 |
Is the Battery Voltage Signal parameter displayed in the specified range? | 9-18 V | Go to Step 3 | Go to Step 4 | ||||||
3 | Is the DTC set as a current DTC? | -- | Go to Step 7 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||
4 |
Is the measured value in the specified range? | 9-18 V | Go to Step 6 | Go to Step 5 | ||||||
5 | Test the battery positive voltage circuit for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Battery Inspection/Test | ||||||
6 | Test all ground circuits of the module for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 | ||||||
7 | Inspect for poor connections at the harness connector of the affected module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 | ||||||
8 | Replace the affected module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||
9 | Operate the system in order to verify the repair. Did you find and correct the condition? | -- | System OK | Go to Step 2 | ||||||
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 Descriptors
DTC B1325 03 : Voltage Below ThresholdDTC B1325 07: Voltage Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Battery Positive Voltage Circuit | B1325 | B1325 | B1325 | B1325 |
Circuit/System Description
The control modules on this vehicle monitor the battery voltage through the battery positive voltage circuits. This vehicle has multiple modules that will set the DTC. For more information on which modules, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Conditions for Running the DTC
| • | The voltages supplied to the control modules are in the range of 7-26 volts. |
| • | The ignition is ON. |
| • | The engine is running. |
Conditions for Setting the DTC
B1325 03
The control module detects a system voltage below the calibrated value usually 9 volts for at least 5 seconds.
B1325 07
The control module detects a system voltage above the calibrated value usually 18 volts for at least 5 seconds.
Action Taken When the DTC Sets
| • | The control module immediately disables all outputs when an out of range voltage condition has been detected, with the exception of GMLAN and Run/Crank relay that are disabled after a 3 minute delay. |
| • | The setting of other DTCs is inhibited. |
Conditions for Clearing the DTC
| • | The DTC clears when the malfunction is no longer present. |
| • | Using the scan tool Clear DTC Information function can clear the DTC. |
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Engine Electrical Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
Circuit/System Verification
With the scan tool installed, ignition ON and the engine OFF, observe the Battery Voltage Signal parameter in the data list of the module setting the DTC The reading should be between 9-18 volts.
Circuit/System Testing
- If the DTC is history refer to Charging System Test .
- Ignition On and the engine running, test for 9.5-17.5 volts between the battery positive voltage and the ground circuits of the affected module.
- If all the circuits test normal, test or replace the affected module.
| ⇒ | If not within the specified range test the B+ circuits for a short to ground or an open/high resistance, and the ground circuits for an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for the affected module replacement, setup, and programming.
