P0098

DTC P0098

Circuit Description

The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT sensor 2 has a signal circuit and a low reference circuit. The IAT sensor 2 measures the temperature of the air entering the induction system. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0098 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0098 Intake Air Temperature (IAT) Sensor 2 Circuit High Voltage

Conditions for Running the DTC

* DTCs P0101, P0102, P0103, P0117, P0118, P0502, and P0503 are not set.
* The engine run time is more than 10 seconds.
* The vehicle speed sensor (VSS) indicates that vehicle speed is less than 1.6 km/h (1 mph).
* The engine coolant temperature (ECT) is more than 50°C (122 °F).
* The mass air flow (MAF) is less than 12 g/s.
* This DTC runs continuously within the enabling conditions in a 250 ms loop.

Conditions for Setting the DTC

The PCM detects that the IAT sensor 2 parameter is less than -39°C (-38°F) for more than 5 seconds.

Action Taken When the DTC Sets

* The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

* The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.

Test Description

Step 1 - Step 10:

Step 11 - Step 16:

The number below refers to the step number on the diagnostic table.
6. This step tests for the proper operation of the circuit in the low voltage range.