For 1990-2009 cars

### Diagnostic Instructions

• | 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.

### DTC Descriptors

DTC P0096: Intake Air Temperature (IAT) Sensor 2 Performance
DTC P0097: Intake Air Temperature (IAT) Sensor 2 Circuit Low Voltage
DTC P0098: Intake Air Temperature (IAT) Sensor 2 Circuit High Voltage
DTC P0099: Intake Air Temperature (IAT) Sensor 2 Circuit Intermittent

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
IAT Sensor 2 Signal | P0097, P0099 | P0098, P0099 | P0098, P0099 | P0098, P0099 | P0096, P2199
Low Reference | -- | P0098, P0099 | P0098, P0099 | P0098, P0099 | P0096, P2199

### Typical Scan Tool Data

#### IAT Sensor 2 Temperature

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine Running Parameter Normal Range: -39 to +140°C (-38 to +284°F)
IAT Sensor 2 Signal | 143°C (289°F) | -40°C (-40°F) | -40°C (-40°F)
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)

### Circuit/System Description

The intake air temperature (IAT) sensor 2 is integrated with the boost pressure sensor. The IAT sensor 2 is a variable resistor that measures the temperature of the air after the turbocharger and the charge air cooler, and before it enters the engine intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit and supplies a ground to the low reference circuit.

### Conditions for Running the DTC

#### P0096

• | DTCs P0097, P0098, P0099 are not set.

• | The engine coolant temperature (ECT) at start-up is less than 75°C (167°F).

• | The ECT reaches a target temperature of greater than 60°C (140°F).

• | The engine is idling.

• | The mass air flow (MAF) is less than 8 g/s.

• | The vehicle speed is less than 10 km/h (6 mph).

| AND

• | The mass air flow (MAF) is between 11-139 g/s.

• | The vehicle speed is greater than 40 km/h (25 mph).

• | This DTC runs continuously within the enabling conditions.

#### P0097

• | The ignition is ON or the engine is running.

• | This DTC runs continuously within the enabling conditions.

#### P0098

• | The engine is running.

• | This DTC runs continuously within the enabling conditions.

#### P0099

• | The ignition is ON or the engine is running.

• | This DTC runs continuously within the enabling conditions.

### Conditions for Setting the DTC

#### P0096

The ECM detects that the IAT sensor 2 is not within range of a calibrated model for greater than 4 seconds.

#### P0097

The ECM detects that the IAT sensor 2 is greater than 140°C (284°F) for greater than 15 seconds at idle.

#### P0098

The ECM detects that the IAT sensor 2 is less than -39°C (-38°F) for greater than 15 seconds at idle.

#### P0099

The ECM detects that the IAT sensor 2 signal is intermittent or has abruptly changed for greater than 4 seconds.

### Action Taken When the DTC Sets

DTCs P0096, P0097, P0098, P0099 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0096, P0097, P0098, P0099 are Type B DTCs.

### Diagnostic Aids

• | Depending on the ambient temperature, an IAT sensor 2 signal circuit that is shorted to the boost pressure sensor signal circuit may cause the IAT Sensor 2 parameter response to be erratic or become stuck at a given value. This condition may not necessarily set a DTC.

• | An IAT sensor signal circuit that is shorted to the boost pressure sensor 5-volt reference circuit will cause a DTC P0098 to set.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

| Important: Determine the ambient temperature by using an accurate thermometer.

• | If the ignition has been OFF for 8 hours or greater, the IAT, the IAT 2 and the engine coolant temperature (ECT) should be within 9°C (16°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool IAT Sensor, IAT 2 Sensor and the ECT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the condition is current.

• | Engine running, observe the scan tool IAT Sensor 2 parameter. The reading should be between -39 and +140°C (-38 and +284°F) depending on the current ambient temperature, the vehicle operating conditions, and the engine load.

### Circuit/System Testing

1. Ignition OFF, disconnect the IAT sensor 2 harness connector at the boost pressure sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool IAT Sensor 2 parameter is less than -39°C (-38°F).

⇒ | If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

4. Install a 3A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool IAT Sensor 2 parameter is greater than 140°C (284°F).

⇒ | If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal replace the ECM.

5. If the circuits test normal, test the IAT sensor 2.

### Component Testing

Measure and record the resistance of the IAT sensor 2 at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance .

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Intake Air Pressure and Temperature Sensor Replacement

• | Control Module References for ECM replacement, setup, and programming