Scan Tool Data List: Overview

The Powertrain OBD System Check is an organized approach to identifying a problem created by an electronic engine control system malfunction. The OBD system check is the starting point for any driveability complaint diagnosis. Some special considerations to keep in mind while making the OBD system check are:

Blocking Drive Wheels
The vehicle drive wheels should always be blocked and the emergency brake set while checking the system.

Cold Oxygen Sensor (O2S 1)
On certain engines, the Oxygen Sensor (O2S 1) may cool down after only a short period of operation at idle. This will cause the system to go into Open Loop. To restore Closed Loop operation, run the engine at part throttle several minutes and accelerate from idle to part throttle a few times.

DESCRIPTION
Use the TYPICAL SCAN DATA VALUES table only after the On-Board Diagnostic System Check has been completed, no DTC(s) were noted and you have determined the on-board diagnostics are functioning properly. Testing and Inspection

Scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The TYPICAL SCAN DATA values represent values that would be seen on a normally running engine.

NOTE: A scan tool that displays faulty data should not be used, and the problem should be reported to the scan tool manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed in the following articles are provided from the OE manual for use in diagnosis. If all values are within the typical range described below, refer to Symptoms for diagnosis. Testing and Inspection

The Typical Scan Data Values table contains all the parameters included in the following data lists arranged in alphabetical order: