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: Device Power Circuit Voltage Below ThresholdDTC B1325 07: Device Power Circuit Voltage Above Threshold
DTC B1325 4A: Device Power Circuit Checksum Error - IPC
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | B1325 03, B1325 4A | B1325 03, B1325 4A | -- | -- |
Ground | -- | B1325 03, B1325 4A | -- | -- |
Circuit/System Description
The control modules on this vehicle monitor the battery voltage on the battery positive (B+) 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 ignition is ON. |
| • | The battery 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 that the system voltage is less than 9 volts for 5 seconds.
B1325 07
The control module detects that the system voltage is greater than 18 volts for 5 seconds.
B1325 4A (Escalade)
The instrument panel cluster (IPC) failed the power on checksum test, either due to low voltage or corrupted memory.
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, which is disabled after a 3 minute delay. |
| • | The setting of other DTCs is inhibited. |
Conditions for Clearing the DTC
The DTC passes when the malfunction is no longer present.
Diagnostic Aids
| • | A high or low voltage value in multiple modules indicates a concern in the charging system. |
| • | Overcharging with a battery charger can cause this DTC to set. |
Reference Information
Schematic Reference
Connector End View Reference
Engine Electrical Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- 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.
- Ignition OFF, disconnect the harness connectors at the appropriate module.
- With the ignition OFF and the scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuit and ground.
- Verify that a test lamp illuminates between the B+ circuit terminals and ground.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminals and ground.
- If all circuits test normal, replace the appropriate module.
| ⇒ | If not within the specified range, refer to Charging System Test . |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the ignition 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.
