P0110 Step 1

DESCRIPTION

The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, monitors the IAT. The IAT sensor has a built in thermistor with a resistance that varies according to the temperature of the intake air. When the IAT is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the ECM (Included in HV Control ECU) as voltage changes (See Fig. 1).
The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes, according to changes in the IAT, the voltage at terminal THA also varies. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve drivability.

HINT:

When any of DTCs P0110, P0112 and P0113 are set, the ECM enters fail-safe mode. During fail-safe mode, the IAT is estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC No.	Proceed to	DTC Detection Condition	Trouble Area
P0110	Step 1	Open or short in Intake Air Temperature (IAT) sensor circuit for 0.5 seconds (1 trip detection logic)	Open or short in IAT sensor circuit IAT sensor (built into MAF meter) HV Control ECU
P0112	Step 4	Short in Intake Air Temperature (IAT) sensor circuit for 0.5 seconds (1 trip detection logic)	Short in IAT sensor circuit IAT sensor (built into MAF meter) HV Control ECU
P0113	Step 2	Open in Intake Air Temperature (IAT) sensor circuit for 0.5 seconds (1 trip detection logic)	Open in IAT sensor circuit IAT sensor (built into MAF meter) HV Control ECU

HINT:

When any of these DTCs are set, check the IAT by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Intake Air.

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

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

1. If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
   
2. Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.
   

1. READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch ON.

3. Turn the tester ON.

4. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

5. Read the value displayed on the tester.

   Standard:

   Same as actual Intake Air Temperature (IAT).
   

   
   

   Result:

   Temperature Displayed	Proceed to
   -40 °C (-40°F)	A
   140°C (284°F) or higher	B
   Same as actual IAT	C

   HINT:

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

B	Go to step 4
C	CHECK FOR INTERMITTENT PROBLEMS

A

2. READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)

1. Disconnect the A3 Mass Air Flow (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.

5. Turn the tester ON.

6. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

7. Read the value displayed on the tester.

   Standard:

   140°C (284°F) or higher
   

8. Reconnect the MAF meter connector.

OK	CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER

NG

3. READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM (INCLUDED IN HV CONTROL ECU))

1. Disconnect the A3 MAF meter connector.

2. Connect terminals THA and E2 of the H34 HV Control ECU connector.

   HINT:

   Before checking, do visual and contact pressure checks on the HV Control ECU connector.

3. Connect the intelligent tester to the DLC3.

4. Turn the ignition switch ON.

5. Turn the tester ON.

6. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

7. Read the value displayed on the tester.

   Standard:

   140°C (284°F) or higher
   

8. Reconnect the MAF meter connector.

OK	REPAIR OR REPLACE HARNESS OR CONNECTOR

NG
CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE HV CONTROL ECU

4. READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)

1. Disconnect the A3 MAF meter connector.

2. Connect the intelligent tester to the DLC3.

3. Turn the ignition switch ON.

4. Turn the tester ON.

5. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

6. Read the value displayed on the tester.

   Standard:

   -40°C (-40°F) or higher
   

7. Reconnect the MAF meter connector.

OK	REPLACE MASS AIR FLOW METER

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5. READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM (INCLUDED IN HV CONTROL ECU))

1. Disconnect the H34 HV Control ECU connector.

2. Connect the intelligent tester to the DLC3.

3. Turn the ignition switch ON.

4. Turn the tester ON.

5. Enter the following menus: Powertrain / Engine / Data List/ Intake Air.

6. Read the value displayed on the tester.

   Standard:

   -40°C (-40°F) or higher
   

7. Reconnect the HV Control ECU connector.

OK	REPAIR OR REPLACE HARNESS AND CONNECTOR

NG
REPLACE HV CONTROL ECU