Code P0112, IAT Sensor Circuit (Low Temperature Indicated): Notes

1994 Chevrolet Lumina BaseSECTION Notes

The Intake Air Temperature (IAT) sensor is a thermistor. PCM applies and monitors 5 volts to sensor. When air is cold, sensor resistance is high and PCM will measure a high signal voltage. If air is warm, sensor resistance is low causing PCM to measure low voltage. Code P0112 will set when following conditions are present.

  • Engine coolant temperature is greater than 140°F (60°C).
  • Mass air flow is less than 12 grams per second.
  • Vehicle speed is less than 25 MPH.
  • IAT signal voltage indicates an intake air temperature less than -29°F (-34°C) for 5 seconds.

With Code P0112 set, PCM will substitute a default value of 61°F (16°C) for intake air temperature. Code P0112 does not illuminate Malfunction Indicator Light (MIL).

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. An open sensor, wire or connection will cause Code P0112 to set. An open circuit would cause Tech-1 to display approximately -40°F (-40°C). This test determines if wiring and PCM are okay.
RENDER: 1.0x

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