P0110/24, P0112/24, P0113/24

DTC Code	DTC Name
P0110/24	Intake Air Temperature Circuit
P0112/24	Intake Air Temperature Circuit Low Input
P0113/24	Intake Air Temperature Circuit High Input

DESCRIPTION

The Intake Air Temperature (IAT) sensor is built into the mass air flow (MAF) meter, and monitors the intake air temperature. The IAT sensor has a built-in thermistor that varies its resistance depending on the temperature of the intake air. When the air temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are communicated to the ECM as changes in voltage (see figure 1).
The IAT sensor is connected to the ECM. The 5 V power source voltage in the ECM is applied to the IAT sensor from terminal THA via resistor R.
Resistor R and IAT sensor are connected in series. When the resistance value of the IAT sensor changes in accordance with changes in the intake air temperature, the voltage at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.

DTC No.	DTC Detection Condition	Trouble Area
P0110/24	Open or short in intake air temperature sensor circuit for 0.5 seconds	Open or short in IAT sensor circuit IAT sensor (built into MAF meter) ECM
P0112/24	Short in intake air temperature sensor circuit for 0.5 seconds	Short in IAT sensor circuit IAT sensor (built into MAF meter) ECM
P0113/24	Open in intake air temperature sensor circuit for 0.5 seconds	Open in IAT sensor circuit IAT sensor (built into MAF meter) ECM

Tech Tips

When DTC P0110/24, P0112/24 or P0113/24 is detected, check the intake air temperature by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / Intake Air.

Temperature Displayed	Malfunction
-40°C (-40°F)	Open circuit
140°C (284°F) or more	Short circuit

MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to calculate the IAT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the IAT sensor and sets a DTC.

Example:

When the sensor voltage output is -40°C (-40°F) (P0113/24) or more than 140°C (284°F) (P0112/24) and if either condition continues for 0.5 seconds or more.

This monitor runs for 0.5 seconds after the ignition switch is turned ON (1 trip detection logic).

WIRING DIAGRAM

INSPECTION PROCEDURE

Tech Tips

If DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

When using intelligent tester:

PROCEDURE

READ OUTPUT DTC

Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine and ECT / DTC.

Read DTCs.

Result

Display (DTC Output)	Proceed To
P0110/24	A
P0112/24	B
P0113/24	C

B

READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS) Click here

C

READ DATA LIST (CHECK FOR OPEN IN WIRE HARNESS) Click here

A

READ DATA LIST (INTAKE AIR TEMPERATURE)

Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

Read the value.

OK
Temperature value is same as the actual intake air temperature.

Result

Temperature Displayed	Proceed to
-40°C (-40°F)	A
140°C (284°F) or more	B
OK (same as actual intake air temperature)	C

Tech Tips

If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
If there is a short circuit, the intelligent tester indicates 140°C (284°F) or more.

B

READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS) Click here

C

CHECK FOR INTERMITTENT PROBLEMS

A

READ DATA LIST (CHECK FOR OPEN IN WIRE HARNESS)
1. Disconnect the A4 MAF meter connector.
2. Connect terminals THA and E2 of the A4 MAF meter wire harness side connector.
3. Turn the ignition switch ON and turn the intelligent tester ON.
4. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
5. Read the value.
  
  OK
  
  Temperature value is 140°C (284°F) or more
OK
CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE MASS AIR FLOW METER

NG
READ DATA LIST (CHECK FOR OPEN IN ECM)
1. Disconnect the A4 MAF meter connector.
2. Connect terminals THA and E2 of the E10 and E11 ECM connectors.
  
  Tech Tips
  
  Before checking, perform a visual and contact pressure check on the ECM connector.
3. Turn the ignition switch ON and turn the intelligent tester ON.
4. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
5. Read the value.
  
  OK
  
  Temperature value is 140°C (284°F) or more
OK
REPAIR OR REPLACE HARNESS AND CONNECTOR

NG

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM
READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the A4 MAF meter connector.
2. Turn the ignition switch ON and turn the intelligent tester ON.
3. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
4. Read the value.
  
  OK
  
  Temperature value is -40°C (-40°F)
OK
REPLACE MASS AIR FLOW METER

NG
READ DATA LIST (CHECK FOR SHORT IN ECM)
1. Disconnect the E10 ECM connector.
2. Turn the ignition switch ON and turn the intelligent tester ON.
3. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
4. Read the value.
  
  OK
  
  Temperature value is -40°C (-40°F)
OK
REPAIR OR REPLACE HARNESS AND CONNECTOR

NG

REPLACE ECM

OK
Temperature value is 140°C (284°F) or more

OK
Temperature value is 140°C (284°F) or more

OK
Temperature value is -40°C (-40°F)

OK
Temperature value is -40°C (-40°F)

When not using intelligent tester:

PROCEDURE

CHECK ECM (THA VOLTAGE)

Turn the ignition switch ON.

Measure the voltage between terminals THA and E2 of the ECM connectors.

Standard voltage

Intake Air Temperature	Specified Condition
20°C (68°F)	0.5 to 3.4 V
60°C (140°F)	0.2 to 1.0 V

OK

CHECK FOR INTERMITTENT PROBLEMS

NG

INSPECT INTAKE AIR TEMPERATURE SENSOR (MASS AIR FLOW METER)
1. Inspect the intake air temperature sensor Click here.
NG
REPLACE MASS AIR FLOW METER

OK

CHECK WIRE HARNESS (ECM - MAF METER)

Disconnect the E10 and E11 ECM connectors.
Disconnect the A4 MAF meter connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

Tester Connection	Specified Condition
E10-29 (THA) - A4-4 (THA)	Below 1 Ω
E11-28 (E2) - A4-5 (E2)	Below 1 Ω
E10-29 (THA) or A4-4 (THA) - Body ground	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE ECM

SFI SYSTEM (w/o Secondary Air Injection System), Diagnostic DTC:P0110/24, P0112/24, P0113/24