SFI SYSTEM, Diagnostic DTC:P0110, P0112, P0113

DTC Code	DTC Name
P0110	Intake Air Temperature Circuit
P0112	Intake Air Temperature Circuit Low Input
P0113	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 Fig. 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.

The resistor R and the 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.	Proceed to	DTC Detection Condition	Trouble Area
P0110	Open or short in intake air temperature sensor circuit for 0.5 seconds	Open or short in IAT sensor circuit for 0.5 seconds	Open or short in IAT sensor circuit IAT sensor (built into MAF meter) ECM
P0112	Short in intake air temperature sensor circuit for 0.5 seconds	Short in IAT sensor circuit for 0.5 seconds	Short in IAT sensor circuit IAT sensor (built into MAF meter) ECM
P0113	Open in intake air temperature sensor circuit for 0.5 seconds	Open in IAT sensor circuit for 0.5 seconds	Open in IAT sensor circuit IAT sensor (built into MAF meter) ECM

DTC No.

Proceed to

DTC Detection Condition

Trouble Area

P0110

Open or short in intake air temperature sensor circuit for 0.5 seconds

Open or short in IAT sensor circuit for 0.5 seconds

Open or short in IAT sensor circuit
IAT sensor (built into MAF meter)
ECM

P0112

Short in intake air temperature sensor circuit for 0.5 seconds

Short in IAT sensor circuit for 0.5 seconds

Short in IAT sensor circuit

IAT sensor (built into MAF meter)

P0113

Open in intake air temperature sensor circuit for 0.5 seconds

Open in IAT sensor circuit for 0.5 seconds

Open in IAT sensor circuit

IAT sensor (built into MAF meter)

Tech Tips

When DTC P0110, P0112 or P0113 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
120°C (248°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 ECM calculates that the ECT is -40°C (-40°F) (P0113) or more than 120°C (248°F) (P0112) and that either condition continues for 0.5 seconds or more, the ECM will set a DTC.

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

If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the next time the engine is started.

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 a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.

PROCEDURE

READ OUTPUT DTC

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

Read DTCs.

Result

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

READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here

READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS) Click here

READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

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

Read the values.

Result

Temperature Displayed	Proceed to
-40°C (-40°F)	A
120°C (248°F) or more	B
OK (same as actual intake temperature)	C

Tech Tips

If there is an open circuit, the tester indicates -40°C (-40°F).
If there is a short circuit, the tester indicates 120°C (248°F) or more.

READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here

CHECK FOR INTERMITTENT PROBLEMS

READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
1. Disconnect the A4 MAF meter connector.
2. Connect terminals THA and E2 of the MAF meter wire harness side connector.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
6. Read the value.
  
  OK
  
  Temperature value is 120°C (248°F) or more
OK
CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE MASS AIR FLOW METER

NG
READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)
1. Disconnect the A4 MAF meter connector.
2. Connect terminals THA and E2 of the E15 ECM wire harness connector.
  
  Tech Tips
  
  Before checking, perform a visual and contact pressure check on the ECM connector.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
6. Read the value.
  
  OK
  
  Temperature value is 120°C (248°F) or more
OK
REPAIR OR REPLACE HARNESS AND CONNECTOR

NG

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM
READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the A4 MAF meter connector.
2. Connect the intelligent tester to the DLC3.
3. Turn the ignition switch ON and turn the tester ON.
4. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
5. Read the value.
  
  OK
  
  Temperature value is -40°C (-40°F)
OK
REPLACE MASS AIR FLOW METER

NG
READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)
1. Disconnect the A4 MAF meter connector.
2. Disconnect the E15 ECM connector.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
6. Read the value.
  
  OK
  
  Temperature value is -40°C (-40°F)
OK
REPAIR OR REPLACE HARNESS AND CONNECTOR

NG

REPLACE ECM