See Figures 1 through 6
The fuel injection or carburetor system, described in detail in Fuel System of this repair guide, is operated along with the ignition system to obtain optimum performance and fuel economy along with a minimum of exhaust emissions. The various sensors listed below are used by the Engine Control Module (ECM) for feedback to determine proper engine operating conditions.
Every sensor listed in this section will not be found in each vehicle/model. Refer to the electronic engine control component diagrams to determine if your vehicle uses a sensor in question, and if so, for the sensor's location.
Although many of the tests listed in the diagnostic section of this guide may be conducted using a Digital Volt/Ohm Meter (DVOM), certain steps or procedures may require use of the Tech1® scan tool (a specialized GM tester) or an equivalent scan/testing tool. If these testers are not available, the vehicle should be taken to a reputable service station which has the appropriate equipment.