WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Battery voltage: The scan tool displays 0.0-16.0 volts. The battery voltage input represents the system voltage measured at the BCM ignition feed input.

Ignition Accessory: Input from ignition switch Accessory circuit. Used to determine power mode. Hot in ACC and ON.

Ignition 0: Input to the control module from the ignition switch indicating the Ignition 0 position. Switch closed (HOT) in ignition switch positions UNLOCK, ACC, ON, and START.

Ignition 1: Input to the control module from the ignition switch indicating the Ignition 1 position. Switch closed (HOT) in ignition switch positions ON and START

Key in Ignition: Input from ignition switch indicating that the ignition key is inserted into the ignition switch. HOT with key in ignition switch.

Module Part Number: Indicates the module part number.

Seed and Key Timer: Indicates the time remaining for programming functions.

Software Part Number: Part number of component program or the ECU. Used to determine applicability to vehicle RPO content.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Scan Tool Data Definitions

Use the Manual With the Right Hardware

When to See a Mechanic

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