1995 Geo Prizm Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Engine Controls - Sensor Operating Range Charts - 1.8L: Introduction: Notes

Sensor operating range information can help determine if a sensor is out of calibration. An out-of-calibration sensor may not set a trouble code, but it may cause driveability problems.

NOTE: Unless stated otherwise in test procedure, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE

Temperature °F (°C) Ohms
-4 (-20) 10,000-20,000
32 (0) 4000-7000
68 (20) 2000-3000
104 (40) 900-1300
140 (60) 400-700
176 (80) 200-400
EGR TEMPERATURE SENSOR RESISTANCE

Temperature °F (°C) Ohms
122 (50) 69,000-88,000
212 (100) 11,000-15,000
302 (150) 2000-4000
INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE

Temperature °F (°C) Ohms
-4 (-20) 10,000-20,000
32 (0) 4000-7000
68 (20) 2000-3000
104 (40) 900-1300
140 (60) 400-700
176 (80) 200-400
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.