DTC    P0110    Intake Air Temperature Circuit

DTC    P0112    Intake Air Temperature Circuit Low Input

DTC    P0113    Intake Air Temperature Circuit High Input

for Preparation Click here


DESCRIPTION


  1. A067628E03
    The Intake Air Temperature (IAT) sensor, built into the Mass Air Flow (MAF) meter, monitors the intake air temperature. The IAT sensor has a thermistor that varies its resistance depending on the intake air temperature. When the intake air temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are reflected as voltage changes to the ECM terminal (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.
DTC Detection Condition
Trouble Area
P0110
Open or short in IAT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. IAT sensor circuit
  2. IAT sensor (built into MAF meter)
  3. ECM
P0112
Short in IAT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. IAT sensor circuit
  2. IAT sensor (built into MAF meter)
  3. ECM
P0113
Open in IAT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. IAT sensor circuit
  2. IAT sensor (built into MAF meter)
  3. ECM

HINT:
After confirming DTC "P0110, P0112 or P0113", use the intelligent tester to confirm the intake air temperature in the "Powertrain / Engine / DTC".


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 intake air temperature. 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 ATF temperature is -40°C (-40°F) or more than 140°C (284°F) and if either condition continues for 0.5 seconds or more, the ECM will set a DTC.
This monitor runs 0.5 seconds after the engine switch is turned on (IG).

WIRING DIAGRAM


A053785E05


INSPECTION PROCEDURE

HINT:
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.

1.READ DATA LIST (INTAKE AIR TEMPERATURE)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the intelligent tester ON.

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

  1. Read the values.

    Standard:
    Same value as the actual IAT.


Result:

Intake Air Temperature
Proceed to
-40°C (-40°F)
A
140°C (284°F) or more
B
OK (same as present temperature)
C

HINT:
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
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS
A


2.READ DATA LIST (CHECK FOR OPEN IN WIRE HARNESS)
A103707E05

  1. Disconnect the E42 MAF meter's connector.

  1. Connect terminals THA of the MAF meter's wire harness side connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the tester ON.

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

  1. Read the value.

    Standard:
    140°C (284°F) or more



OK
REPLACE MASS AIR FLOW METER
NG


3.READ DATA LIST (CHECK FOR OPEN IN ECM)
A103708E10

  1. Disconnect the E42 MAF meter connectors.

  1. Connect the E6 and E8 connectors.

    HINT:
    Before checking, do a visual and contact pressure check for the ECM connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the tester ON.

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

  1. Read the value.

    Standard:
    140°C (284°F) or more



NG
REPLACE ECM
OK

REPAIR OR REPLACE HARNESS AND CONNECTOR 

4.READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS)
A075766E10

  1. Disconnect the E42 MAF meter connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the tester ON.

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

  1. Read the value.

    Standard:
    -40°C (-40°F) or more



OK
REPLACE MASS AIR FLOW METER
NG


5.READ DATA LIST (CHECK FOR SHORT IN HARNESS OR ECM)
A103709E08

  1. Disconnect the E42 MAF meter connector.

  1. Disconnect the E6 and E8 ECM connectors.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the tester ON.

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

  1. Read the value.

    Standard:
    -40°C (-40°F) or more



NG
REPLACE ECM
OK

REPAIR OR REPLACE HARNESS AND CONNECTOR