The throttle actuator control (TAC) system is made up of the following: APP Sensor 1, APP Sensor 2, TPS 1, TPS 2, Throttle Actuator Motor. This simplified wiring diagram includes the electronic throttle body circuit diagram and the APP sensor assembly circuit diagram.
The above TAC circuit wiring diagrams apply only to the 2006 and 2007 4.2L Chevrolet TrailBlazer and GMC Envoy.
The TAC system wiring diagram for the 2002-2005 4.2L Chevrolet TrailBlazer and GMC Envoy can be found here: TAC System Wiring Diagram (2002-2005 4.2L Chevrolet TrailBlazer).
The electronic throttle body TPS 1, TPS 2, and throttle actuator motor tests can be found here: Electronic Throttle Body Tests (2002-2007 4.2L Chevrolet TrailBlazer).
The APP sensor 1 and APP sensor 2 tests can be found here: How To Test APP Sensor 1 And 2 (2004-2007 4.2L Chevrolet TrailBlazer).
More GM 4.2L Test Tutorials
I've written quite a few tutorials for the 4.2L Chevrolet TrailBlazer And GMC Envoy. You can find them here: GM 4.2L Index Of Articles.
Here's a sample of the tutorials you'll find there:
- How To Test For A Blown Head Gasket (2002-2009 4.2L Chevrolet TrailBlazer).
- How To Test The MAP Sensor (2002-2007 4.2L Chevrolet Trailblazer).
- How Often Should I Replace The Spark Plugs? (2002-2009 4.2L Chevrolet TrailBlazer).
- How To Test Engine Compression (2002-2009 4.2L Chevrolet TrailBlazer).
- Camshaft Position Actuator Solenoid Test (2002-2009 4.2L Chevrolet TrailBlazer).
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