Circuit Description
The body control module (BCM) monitors the battery voltage through the battery voltage signal circuit. Refer to Body Control System Schematics .
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1325 Device Power 1 Circuit Voltage
Conditions for Running the DTC
The voltage supplied to the BCM is in the range of 7-26 volts.
Conditions for Setting the DTC
B1325 Type 03
| • | The BCM detects a system voltage below 9 volts. |
| • | The above condition is present at least 5 seconds. |
B1325 Type 07
| • | The BCM detects a system voltage above 18 volts. |
| • | The above condition is present at least 5 seconds. |
Action Taken When the DTC Sets
| • | The BCM immediately disables all outputs when a high voltage condition was detected, with the exception of GMLAN and Run/Crank relay that are disabled after a 3 minutes 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. |
Diagnostic Aids
| • | The following may cause an intermittent: |
| - | A damaged terminal |
| - | A backed out terminal |
| - | A poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| • | When diagnosing an intermittent short or an open, manipulate the wire harness while watching the test equipment for changes. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Body Control System Schematics | ||||
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 Diagnostic Aids |
4 |
Is the measured value in the specified range? | 9-18 V | Go to Step 6 | Go to Step 5 |
5 | Test the Battery Voltage Signal circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Charging System Test |
6 | Test the all of ground circuits of the BCM 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 module harness connectors. 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 BCM. 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 |
