P0111-INTAKE AIR TEMPERATURE SENSOR 1 PERFORMANCE

Special Tools: Click to display a list of tools used in this procedure

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

Intake Air Temperature Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. Following a start to run delay time, the outputs of the Ambient, Engine Coolant and Intake Air Temperature sensors will be compared. If the Engine Coolant and Ambient Air Temperature Sensors agree, and the Intake Air Temperature does not agree, the Intake Air Temperature Sensor is declared as irrational. If declared irrational a second comparison will be done after a short drive cycle.

When Monitored:
With the engine off time greater than 480 minutes and ambient temperature greater than -7°C (19.4°F).
Set Condition:
After a calibrated amount of cool down time, the Powertrain Control Module (PCM) compares the Ambient Air Temperature (AAT), Engine Coolant Temperature (ECT), and Intake Air Temperature (IAT) Sensor values. If one sensor value is not within 10°C (18°F) of the other temperature sensors for two consecutive trips, a DTC will set. Three good trips to turn off the MIL.

Possible Causes
(K21) IAT SIGNAL CIRCUIT SHORTED TO VOLTAGE
(K21) IAT SIGNAL CIRCUIT SHORTED TO GROUND
(K21) IAT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
(K21) IAT SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
(K900) SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
INTAKE AIR TEMPERATURE (IAT) SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

1. DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE

NOTE: Diagnose any CAN - C Communication DTCs before continuing.

1.	Turn the ignition off.

2.	If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -7°C (19.4°F).

3.	Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.

4.	With a scan tool, select View DTCs.

Is the status Active or Pending for this DTC?

Yes

Go To 3

Go To 2

2. INTAKE AIR TEMPERATURE

1.	Turn the ignition off.

2.	Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -7°C (19.4°F) until the engine coolant temperature is equal to ambient temperature.

3.	Turn the ignition on.

4.	With a scan tool, compare the AAT, ECT, and IAT sensor values.

Is the Intake Air Temperature Sensor value within 10°C (18°F) of the other two sensor values?

Yes

Perform the INTERMITTENT CONDITION diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 3

3. (K21) IAT SIGNAL CIRCUIT SHORTED TO VOLTAGE

1.	Turn the ignition off.

2.	Disconnect the Intake Air Temperature Sensor (IAT) harness connector.

3.	Disconnect the PCM C2 harness connectors.

4.	Turn the ignition on.

5.	Measure the voltage of the (K21) IAT Signal circuit in the Intake Air Temperature Sensor harness connector.

Is there any voltage present?

Yes

Repair the (K21) IAT Signal circuit for a short to voltage.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 4

4. (K21) IAT SIGNAL CIRCUIT SHORTED TO GROUND

1.	Turn the ignition off.

2.	Measure the resistance between ground and the (K21) IAT Signal circuit in the Intake Air Temperature Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

Go To 5

Repair the (K21) IAT Signal circuit for a short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

5. (K21) IAT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

1.	Measure the resistance between the (K21) IAT Signal circuit and the (K900) Sensor Ground circuit in the Intake Air Temperature Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

Go To 6

Repair the (K21) IAT Signal circuit for a short to the (K900) Sensor Ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

6. (K21) IAT SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

CAUTION:

Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

1.	Connect the Adapter, GPEC Diagnostic 10436 .

2.	Measure the resistance of the (K21) IAT Signal circuit between the Intake Air Temperature Sensor harness connector and the GPEC Adaptor.

Is the resistance below 5.0 Ohms?

Yes

Go To 7

Repair the (K21) IAT Signal circuit for an open circuit or high resistance.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

7. (K900) SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE

1.	Measure the resistance of the (K900) Sensor Ground circuit between the Intake Air Temperature Sensor harness connector and the GPEC Adaptor.

Is the resistance below 5.0 Ohms?

Yes

Go To 8

Repair the (K900) Sensor Ground for an open circuit or high resistance.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

8. INTAKE AIR TEMPERATURE SENSOR

1.	Turn the ignition off.

2.	Connect the PCM harness connectors.

3.	Connect a jumper wire between the (K900) Sensor Ground circuit and the (K21) IAT Signal circuit in the Intake Air Temperature Sensor harness connector.

4.	Turn the ignition on.

5.	Using the scan tool, read the Intake Air Temperature Sensor signal voltage.

Is the voltage below 1.0 Volt with the jumper wire in place?

Yes

Replace the Intake Air Temperature Sensor in accordance with the Service Information. (Refer to 14 - Fuel System/Fuel Injection/SENSOR, Air Temperature - Removal) .
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Go To 9

9. POWERTRAIN CONTROL MODULE (PCM)

1.	Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Intake Air Temperature Sensor and the Powertrain Control Module (PCM).

2.	Look for any chafed, pierced, pinched, or partially broken wires.

3.	Look for broken, bent, pushed out or corroded terminals.

4.	Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

5.	Look for the data to change or for the DTC to reset during the wiggle test.

6.	Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. (Refer to 08 - Electrical/8E - Electronic Control Modules/MODULE, Powertrain Control - Removal) .
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

P0111-INTAKE AIR TEMPERATURE SENSOR 1 PERFORMANCE

Theory of Operation

Possible Causes