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 Descriptor

DTC P0097 12: Intake Air Temperature Sensor 2 Circuit Low Voltage
DTC P0098 11: Intake Air Temperature Sensor 2 Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Signal | P0097 12 | P0098 11 | P0098 11 | --
Low Reference | -- | P0098 11 | P0098 11 | --

### Circuit/System Description

The intake air temperature (IAT) sensor 2 is an integral part of the turbocharger pressure sensor. The IAT sensor is a variable resistor that measures the temperature of the intake 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

### Conditions for Running the DTC

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

• | The DTCs run continuously once the above conditions are met.

### Conditions for Setting the DTC

#### P0097

The ECM detects that the IAT sensor 2 is less than 160 mV for greater than 0.5 s.

#### P0098

The ECM detects that the IAT sensor 2 parameter is greater than 4.9 V for greater than 0.5 s.

### Action Taken When the DTC Sets

DTCs P0097 and P0098 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0097 and P0098 are Type B DTCs.

### Diagnostic Aids

• | 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.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component 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

Control Module References

### Circuit/System Verification

1. Ignition On, observe the DTC information with a scan tool. DTCs P0097 or P0098 should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B111 Turbocharger Boost Pressure Sensor.
2. Ignition OFF, test for less than 5 Ω between the low reference circuit terminal 1 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 K20 Engine Control Module (ECM).

3. Ignition ON, verify the scan tool IAT Sensor 2 parameter is greater than 4.8 V.

⇒ | If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

4. Install a 10 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool IAT Sensor 2 parameter is less than 0.3 V.

⇒ | If greater 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 K20 Engine Control Module (ECM).

5. If all circuits test normal, test or replace the B111 Turbocharger Boost Pressure Sensor.

### Component Testing

#### Static Test

Measure and record the resistance between the IAT signal circuit terminal 2 and the low reference circuit terminal 1at various ambient temperatures. Compare those measurements to the Temperature Versus Resistance table and verify that the resistance is within 5% of the specification.

If not within the specified range, replace the B111 Turbocharger Boost Pressure Sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Link

• | Engine Control Module Replacement for ECM replacement, setup, and programming