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 Descriptor

DTC B1405: Device Voltage Reference Output 2 Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Battery Current Sensor Supply Voltage Circuit | B1405 | B1405 | -- | --
Battery Current Sensor Signal Circuit | B1405 | B1405 | -- | --
Battery Current Sensor Low Reference Circuit | -- | B1405 | -- | --

### Circuit/System Description

The battery current sensor is a 3-wire hall effect current sensor. The battery current sensor monitors the battery current. It directly inputs to the body control module (BCM). It creates a 5-volt pulse width modulation (PWM) signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-95 percent. Between 0-5 percent and 95-100 percent are for diagnostic purposes.

### Conditions for Running the DTC

• | The ignition is ON.

• | The engine is running.

### Conditions for Setting the DTC

The BCM detects a duty cycle of PWM input signal is less than 4 percent or more than 96 percent for more 33 seconds.

### Action Taken When the DTC Sets

The driver information center (DIC) displays the SERVICE BATTERY CHARGING SYSTEM warning message.

### Conditions for Clearing the DTC

The DTC clears as current status when the battery sensed current returns to normal range for more than 5 seconds.

### 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 Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the battery current sensor.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit terminal B and ground.

⇒ | If the greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal replace the BCM.

3. Ignition ON, test for 4.8- 5.2 volts between the battery current sensor supply voltage circuit terminal A and ground.

⇒ | If less than the specified range , test the supply voltage circuit for a short to ground or an open/high resistance. If the circuit test normal replace the BCM.

⇒ | If greater than specified range , test the supply voltage circuit for a short to voltage.

4. Ignition ON, test for 4.8-5.2 volts between the battery current sensor signal circuit terminal C and ground.

⇒ | If less than the specified range,test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal replace the BCM.

⇒ | If greater than specified range , test the signal circuit for a short to voltage.

5. If all circuits test normal test or replace the battery current sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Control Module References for BCM replacement, setup, and programming

• | Battery Current Sensor Replacement