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 P0114 00: Intake Air Temperature (IAT) Sensor Circuit Intermittent

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance
--- | --- | --- | --- | --- | ---
IAT Sensor Signal | P0112 00, P0114 00 | P0113 00, P0114 00 | P0113 00, P0114 00 | P0113 00, P0114 00 | P0111 00, P0114 00
Low Reference | -- | P0113 00, P0114 00 | P0113 00, P0114 00 | P0113 00, P0114 00 | P0111 00, P0114 00

### Typical Scan Tool Data

#### IAT Sensor

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: The ignition is ON, or the engine is running Parameter Normal Range: Varies with ambient temperature
IAT Sensor Signal | 129°C (264°F) | -40°C (-40°F) | -40°C (-40°F)
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)

### Circuit/System Description

The IAT sensor is a variable resistor that measures the temperature of the air when it first enters the induction system. The engine control module (ECM) supplies 5 V to the IAT signal circuit and a ground for the shared IAT low reference circuit.

### Conditions for Running the DTC

• | DTC P0111 00, P0112 00, or P0113 00 is not set.

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

• | The ignition voltage is greater than 9 V.

### Conditions for Setting the DTC

The ECM detects that the IAT sensor signal has abruptly changed a minimum of 10°C (18°F) warmer or colder for greater than 2 s.

### Action Taken When the DTC Sets

DTCs P0114 00 is a Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0114 00 is a Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Air Intake System Description

#### 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 for scan tool information

### Circuit/System Verification

1. If the ignition has been OFF for 8 h or greater, the IAT, the ambient air temperature, and the engine coolant temperature (ECT) should be within 9°C (16°F) of each other. Ignition ON, observe the scan tool IAT Sensor, Ambient Air Temperature, and the ECT Sensor 1 parameters. Compare those sensor parameters to each other to determine if the condition is current.
2. Drive the vehicle under various operating conditions. Observe the scan tool IAT Sensor parameter and the Ambient Air Temperature parameter. The readings should be near each other.
3. 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 for 90 s, disconnect the harness connector at the B66 Intake Air Temperature (IAT) Sensor.
2. Test for less than 5 Ω between the B66 Intake Air Temperature (IAT) Sensor low reference circuit terminal B and ground.

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

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

⇒ | If greater than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

⇒ | If less than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

4. If all circuits test normal, test or replace the B66 Intake Air Temperature (IAT) Sensor.

### Component Testing

#### Static Test

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Intake Air Temperature Sensor Replacement

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