P0110

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0110: Intake Air Temperature Circuit

DTC P0110 - Intake Air Temperature Circuit

DTC P0112 - Intake Air Temperature Circuit Low Input

DTC P0113 - Intake Air Temperature Circuit High Input

DESCRIPTION





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.





HINT: After confirming DTC P0110, P0112 or P0113, use the Techstream to confirm the intake air temperature by entering the following menus: Powertrain / Engine and ECT / Data List / Intake Air.





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:
If the sensor output voltage is 4.91 V for 0.5 seconds or more, the ECM determines that there is an open in the IAT sensor circuit, and sets DTC P0113. Conversely, if the output voltage is more than 0.18 V for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0112. If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P0110:





P0112:





P0113:





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: Read freeze frame data using the Techstream. 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

1. READ VALUE USING TECHSTREAM (INTAKE AIR TEMPERATURE)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(d) Read the values.
OK:
Same value as the actual IAT
Result:





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

C -- CHECK FOR INTERMITTENT PROBLEMS
B -- READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)
A -- Continue to next step.
2. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS)




(a) Disconnect the M1 MAF meter connector.
(b) Connect terminal THA and E2 of the MAF meter's wire harness side connector.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch ON and turn the tester ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(f) Read the value.
OK:
Temperature value is 140°C (284°F) or more
OK -- REPLACE MASS AIR FLOW METER
NG -- Continue to next step.
3. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN ECM)




(a) Disconnect the M1 MAF meter connector.
(b) Connect terminal THA of the E4 ECM connector and terminal E2 of the E2 ECM connector.
HINT: Before checking, perform a visual and contact pressure check for the ECM connector.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch ON and turn the tester ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(f) Read the value.
OK:
Temperature value is 140°C (284°F) or more
NG -- REPLACE ECM
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR
4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)




(a) Disconnect the M1 MAF meter connector.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch ON and turn the tester ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(e) Read the value.
OK:
Temperature value is -40°C (-40°F)
OK -- REPLACE MASS AIR FLOW METER
NG -- Continue to next step.
5. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN HARNESS OR ECM)




(a) Disconnect the M1 MAF meter connector.
(b) Disconnect the E2 and E4 ECM connectors.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch ON and turn the tester ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(f) Read the value.
OK:
Temperature value is -40°C (-40°F)
NG -- REPLACE ECM
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR