Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 33 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.

Inspect for the following conditions:

Mass airflow (MAF) is compared to a calculated MAF based upon Manifold Absolute Pressure (MAP), Throttle Position (TP), and engine RPM readings. A skewed or unresponsive MAP sensor at KEY ON will cause predicted airflow value to be inaccurate. Compare MAP and TP sensor values to that of a known good vehicle.
Faulty ECT sensor. Using a scan tool, compare engine coolant temperature with Intake Air Temperature (IAT) on a completely cool engine. ECT should be within 5°F (3°C) of intake air temperature. For an intermittent condition, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - TRUCKS article.