In this video I’ll show you how to use scan data and service information to diagnose a P0106 MAP/BARO Pressure Circuit Out of Range code on a 2005 Chevrolet Trailblazer. Reading and understanding the code information, as well as the Snap-On Troubleshooter, were key in repairing this fault. I also demonstrate how to safely clean an electronic throttle body, a very common feature on modern vehicles of all makes. This false MAP sensor trouble code caused by a dirty throttle body in not unique to the Trailblazer. I have also seen this problem with other model GM vehicles as well.

Engine Performance Diagnostics chapter 20 pages 2 - 4, 12-14

symptoms 50

  • check engine light (P0106)
  • possible low idle, stalling

fix 50

  • cleaning and relearning the electronic throttle body

test shown enh 50

  • using service information and flow charts to understand PCM code set criteria and diagnostic strategies
  • using scan data to identify a dirty electronic throttle body
  • inspecting and cleaning an electronic throttle body
  • causes of a false MAP sensor trouble code

Tools used

  • scan tool
  • shop rag and carburetor/intake cleaner

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(Chapter 20) Idle Speed Problems and Testing

Related videos:

Chapter 20 “Idle Speed Controls - preview (an SD Premium video):


P0506 IAC System RPM below expected (vacuum leak) - Ford:


False mass air flow/idle control system codes - vacuum leak - Pontiac:


How to test an idle air control valve (IAC) using a Picoscope - Ford:


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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium. There is a 14 day free trial.

On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!