This page is to provide information about sensors used by GM

MAP/pressure sensors

There are several varieties of pressure sensors from GM: Map sensors in 3 varieties (1 bar, 2 bar, 3 bar), and a barometric pressure sensor. 1 Bar sensors are good for NA engines, they measure from 0 (vacuum) to approximately atmospheric pressure. A 2 Bar sensor is good for 15 PSI of boost, and a 3 Bar unit is good for 30 psi of boost.

They all share a common pinout, although the connector keying may be different:

Version Part numbers Description
1 Bar
  • GM part # 2503679 
  • standard part # AS-5 
 Pretty much any normally aspirated TBI GM car, plus plenty of others 
2 Bar
  • GM part # 16009886 
  • Wells part # SU-129 
  • standard part # AS-4 
 91-93 GMC Syclone & Typhoon 4.3 turbo
87-90 Pontiac Sunbird Turbo 2.0
84-86 Sunbird (actually any J-car) turbo 1.8 
3 Bar
  • GM part # 16040749 
Baro
  • GM part # 1600683 
 Has a piece of foam over the pressure port.
100 Kpa, 4.9V 90 Kpa, 4.4V 80 Kpa, 3.8V 70 Kpa, 3.3V 60 Kpa, 2.7V 50 Kpa, 2.2V 40 Kpa, 1.7V 30 Kpa, 1.1V 20 Kpa, 0.6V 10 Kpa, 0.3V

 

IAT/CTS sensors

IAT and CTS sensors (Inlet air temp and cooland temp). These are sensors that provide a variable resistance according to temperature. IAT is sometimes referred to as MAT (Mass Air Temp)
Temperature (C) Temperature (F) IAT resistance CTS resistance
100 210 185 177
90 194 241
80 176 332
70 158 450 467
60 140 667
50 122 973
40 104 1800 1,459
30 86 2,238
20 68 3400 3,520
10 50 5,670
0 32 7500 9,420
-10 14 13,500 16,180
-20 -4 25,000 28,680
-30 -22 52,700
-40 -40 100,700 100,700 




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