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 engine intake manifold. 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 low IAT signal voltage, indicating a high temperature, DTC P0097 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0097 Intake Air Temperature (IAT) Sensor 2 Circuit Low Voltage
Conditions for Running the DTC
| • | DTCs 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 more than 40 km/h (25 mph). |
| • | The engine coolant temperature (ECT) is less than 110°C (230°F). |
| • | 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 more than 149°C (300°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. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 | Observe the IAT sensor 2 parameter with a scan tool. Is the IAT sensor 2 parameter more than the specified value? | 149°C (300°F) | Go to Step 4 | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions and Inducing Intermittent Fault Conditions in Wiring Systems |
4 |
Is the IAT sensor 2 parameter less than the specified value? | -39°C (-38°F) | Go to Step 6 | Go to Step 5 |
5 | Test the signal circuit of the IAT sensor 2 for a short to ground or a short to the IAT sensor 2 low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 |
6 | Test for an intermittent and for a poor connection at the IAT sensor 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
7 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
8 | Replace the IAT sensor 2. Refer to Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
9 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 11 |
11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
