Important Safety Notice
Appropriate repair methods and procedures are essential for the safe, reliable operation of all motor vehicles, as well as the personal safety of the individual doing the work. This article provides general directions for repairing vehicles with tested, effective techniques. Following them will help ensure reliability. There are numerous variations in procedures, techniques, tools, and parts for repairing vehicles, as well as in the skill of the individual doing the work. This article cannot possibly anticipate all such variations and provide advice or cautions as to each. Accordingly, anyone who departs from the instructions provided in this article must first establish that they compromise neither their personal safety nor the vehicle integrity by their choice of methods, tools, or parts.
This pinpoint test is intended to diagnose the following:
- Mass air flow (MAF) sensor (12B579).
- Harness circuits: MAF SIG, MAF RTN, vehicle power (VPWR), and power ground (PWRGND).
- Powertrain control module (PCM) (12A650).BAROMETRIC PRESSURE REFERENCE CHART
Barometric Pressure (in. Hg.) Barometric Pressure (kPa) BARO/MAP PID (Hz) Altitude Above Sea Level (ft) 3.5 11 89.3 20 69 130 10,000 21 71 132 9,000 22 75 136 8,000 23 78 138 7,000 24 82 142 6,000 25 84 144 5,000 26 89 147 4,000 27 93 151 2,000 29 98 155 1,000 30 102 159 0 (sea level) 31.875 105 162 -500