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 B1424: Device 1 Voltage Low

### Circuit/System Description

Voltage at Pass Key 3 module is lower than the voltage being reported on the serial data line.

### Conditions for Running the DTC

The ignition must be in Accessory or Run mode for this code to set.

### Conditions for Setting the DTC

Module battery voltage between low voltage limits 6-9 volts for a minimum of 2 seconds and serial data voltage is greater than normal low voltage 9 volts.

### Action Taken When the DTC Sets

Security telltale ON.

### Conditions for Clearing the DTC

Module battery voltage is greater than normal voltage low limit 9 volts.

### Reference Information

#### Schematic Reference

Immobilizer Schematics

#### Connector End View Reference

Immobilizer Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Circuit/System Testing

1. Ignition OFF, disconnect the theft deterrent module (TDM) harness connector.
2. Measure and record the voltage at the battery terminals. Ignition in ON position, measure the voltage between the accessory voltage circuit and the ground circuit of the TDM. Verify that the voltage readings do not differ more than 1 volt.

⇒ | If greater than 1 volt, test the accessory voltage circuit and the ground circuit of the TDM for an open/high resistance. If the circuits test normal, replace the TDM.

3. Refer to Charging System Test .

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for TDM replacement, setup, and programming