How To: Computer Test of a Check Engine Light in a 2004 Cavalier

The 2004 Chevrolet Cavalier is equipped with an OBD II port for engine diagnostics.

The 2004 Chevrolet Cavalier is equipped with an OBD II port. The OBD II port provides access to the vehicle's onboard computer for diagnostic code access. The onboard computer interfaces with the Cavalier's engine-system sensors to collect data. The check engine light is triggered when the computer is notified of an abnormal condition. Retrieve the diagnostic codes from the OBD II port using a scan tool or OBD II reader. OBD provides decoding either directly on the tool, through a user's manual or through the OBD website to enable diagnosis of the cause of the check engine light.

Things You'll Need

• OBD II reader or scan tool

Instructions

1. Park the Cavalier and turn off the engine.

2. Open the driver's side door and locate the OBD II port under the steering wheel. It is slightly to the left of the steering wheel under the dash.

3. Connect the OBD II reader or scan tool to the port using the provided cable. Turn on the device and allow it to initialize.

4. Place the key into the ignition and turn the ignition to the "on" position. Do not start the engine.

5. Allow the tool to pull the diagnostic codes from the onboard computer. The codes will be displayed on the tool. If the diagnostic information is not displayed alongside the code, look up the code in the reference manual provided with the tool or through the OBD website.

References

• Service Mix: Performance Tuners & Programmers
• OBD Clearinghouse: Chevrolet Cavalier 2004 OBD II Port Information
• OBD II: General Motors Driving Cycle

Resources

• OBD II: On-Board Diagnostic System