For 1990-2009 cars

### 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 1 Circuit Voltage Below Threshold
DTC B1325 07: Device Power 1 Circuit Voltage Above Threshold
DTC B1325 4A: Device Power 1 Circuit Checksum Error

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
B+ | B1325 | B1325 | -- | --
Ground | -- | 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 V.

• | The ignition is ON.

• | The engine is running.

### Conditions for Setting the DTC

#### B1325 03

The control module detects a system voltage below 9 V for 5 seconds.

#### B1325 07

The control module detects a system voltage above 18 V for 5 seconds.

#### B1325 4A

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 serial data 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.

### Diagnostic Aids

• | A high or low voltage DTC set in multiple modules indicates a concern in the charging system.

• | A possible cause of this DTC could be overcharging with a battery charger or jump starting.

• | A high or low voltage value in multiple modules indicates a concern in the charging system.

### Reference Information

#### Schematic Reference

Control Module References

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Charging System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Engine running measure and record the voltage at the battery terminals. Verify that the battery voltage is 12.5-15.5 V.

⇒ | If the battery voltage is not within the specified range, refer to Charging System Test

2. Engine running, observe the scan tool Battery Positive Voltage parameter in the data list of the module setting the DTC. The reading should be between 12.6 and 15.5 V.

### Circuit/System Testing

1. Ignition OFF. Disconnect the harness connectors of the module that set the DTC.
2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 Ω between the ground circuit(s) and ground:

⇒ | If greater than the specified value, test the ground circuit(s) for an open/high resistance.

3. Ignition ON, verify a test lamp illuminates between the battery positive voltage circuit(s) and ground.

⇒ | If not within the specified range, test the appropriate battery positive voltage circuit for a short to ground or an open/high resistance.

4. If all the circuits test normal, replace the appropriate control module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for the appropriate control module replacement, setup, and programming.