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 Circuit Voltage Below Threshold
DTC B1325 07: Device Power Circuit Voltage Above Threshold
DTC B1325 4A: Device Power Circuit Checksum Error - HUD/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 following control modules monitor the battery voltage through the battery positive (B+) voltage circuits:

• | Head-up display (HUD)

• | Instrument panel cluster (IPC)

• | Passenger presence system (PPS)

• | Radio

• | Ultrasonic parking aid (UPA)

If any of the control modules listed detect that the battery voltage is out of range, it will set DTC B1325.

### Conditions for Running the DTC

• | The ignition is ON.

• | The battery voltage supplied to the control module 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

The HUD or 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, 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 or jump starting can cause this DTC to set.

### Reference Information

#### Schematic Reference

• | Head Up Display Schematics

• | Instrument Cluster Schematics

• | SIR Schematics

• | Radio/Navigation System Schematics

• | Object Detection Schematics

• | Starting and Charging Schematics

#### 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 Testing

1. 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.

⇒ | If not within the specified range, refer to Charging System Test .

2. Ignition OFF, disconnect the harness connectors at the appropriate module.
3. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuits listed below and ground.

• | Terminal 2 (IPC)

• | Terminal 4 (HUD)

• | Terminal D (PPS)

• | Terminal 5 X1 (Radio UQG)

• | Terminal 8 X1 (Radio U42/UQF/UQA/UQS)

• | Terminal 7 X1 (UPA)

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

4. Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.

• | Terminal 1 (IPC)

• | Terminal 6 (HUD)

• | Terminal A (PPS)

• | Terminal 1 X1 (UPA, Radio U42/UQF/UQG)

• | Terminal 4 X1 (Radio UQA/UQS)

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. If all 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 module replacement, setup, and programming.