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• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
The inlet air temperature (IAT) sensor 1 is an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the inlet air. The engine control module (ECM) supplies 5 V to the IAT signal circuit and supplies a ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
---|---|---|
Cold | High | High |
Warm | Low | Low |
• | The ignition is ON or the engine is running. |
• | The ignition voltage is greater than 8.5 V. |
• | The DTCs run continuously once the above conditions are met. |
The ECM detects that the IAT 1 deviates less than 1.5°C (35°F) since engine start.
The ECM detects that an IAT 1 circuit is shorted to ground.
The ECM detects that an IAT 1 circuit is open or shorted to voltage.
DTCs P0111 00, P0112 00 and P0113 00 are Type B DTCs.
DTCs P0111 00, P0112 00 and P0113 00 are Type B DTCs.
• | If the engine has sat overnight, the IAT sensor and the engine coolant temperature (ECT) sensor values should display within 3°C (5°F). |
• | High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may set a DTC. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If less than the specified range, test the signal circuit for an open or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
Test and record the resistance between the signal circuit terminal 3 and the low reference circuit terminal 1 at various ambient temperatures. Compare those measurements to the Temperature Versus Resistance : Exhaust Temperature Sensor → ECT and IAT Sensor table and verify that the resistance is within 5% of the specification.
⇒ | If not within the specified range, replace the B75B Mass Air Flow/Intake Air Temperature Sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |
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