Test Notes

IAT Sensor And Related Components:

SIGNAL FUNCTIONS
The Intake Air Temperature (IAT) sensor is a thermistor-type sensor with a variable resistance that changes when exposed to different temperatures. When interfaced with the Powertrain Control Module (PCM), it produces a 0 to 5 volt analog signal that will measure temperature.

The IAT sensor's primary function is to measure ambient air temperature in order to determine when the exhaust back pressure device is needed.

Pinpoint Test C Schematic:

DETECTION/MANAGEMENT
An IAT signal that is detected out of range high or low by the PCM will cause the engine to ignore the IAT signal, disable exhaust back pressure operation and assume an ambient temperature of 59°F (15°C).





Connector Checks To Ground (B-)
Check with sensor connector disconnected and ignition key and all accessories OFF.





Connector Voltage Checks
Check with sensor disconnected and ignition key ON





Harness Resistance Checks
Check with Breakout Box installed on harness only.


NOTE: After removing connectors always check for damaged pins, corrosion, loose terminals, etc..

IAT Sensor Temperature/Voltage Chart:

DTC DESCRIPTION
152 = Signal Voltage was greater than 4.59 volts more than for 0.20 seconds.
151 = Signal voltage was less than 0.13 volts for more than 0.20 seconds.