P0110

2AZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0110,P0112,P0113: Intake Air Temperature Circuit Malfunction

DTC P0110 - Intake Air Temperature Circuit Malfunction

DTC P0112 - Intake Air Temperature Circuit Low Input

DTC P0113 - Intake Air Temperature Circuit High Input

DESCRIPTION




- The Intake Air Temperature (IAT) sensor, in 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 the hybrid vehicle 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, the voltage at terminal THA also varies according to changes in the IAT. 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.





HINT: When any of these DTCs are set, check the IAT by selecting the following menu items on the Techstream: Powertrain / Engine / Data List / All Data / Intake Air.





MONITOR DESCRIPTION

The ECM (included in the hybrid vehicle control ECU) 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 malfunction in the IAT sensor and sets a DTC.
Example:
If the sensor output voltage is more than 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 less 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. The ECM (included in the hybrid vehicle control ECU) 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.

PROCEDURE

1. READ DTC OUTPUT
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the Techstream on.
(c) Select the following menu items: Powertrain / Engine / Trouble Code.
(d) Read the DTCs.
Result:






C -- READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS)
B -- READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)
A -- Continue to next step.
2. READ VALUE USING TECHSTREAM (INTAKE AIR TEMPERATURE)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the tester on.
(d) Select the following menu items: Powertrain / Engine / Data List / All Data / Intake Air.
(e) Read the value displayed on the tester.
Standard:
Same as actual Intake Air Temperature (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 higher.

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




(a) Confirm good connection of the Mass Air Flow (MAF) meter.
(b) Disconnect the C2 MAF meter connector.
(c) Connect terminals THA and E2 of the MAF meter wire harness side connector.
(d) Connect the Techstream to the DLC3.
(e) Turn the power switch on (IG).
(f) Turn the tester on.
(g) Select the following menu items: Powertrain / Engine / Data List / All Data / Intake Air.
(h) Read the value displayed on the tester.
Standard value:
140°C (284°F) or higher
(i) Reconnect the MAF meter connector.
OK -- REPLACE MASS AIR FLOW METER
NG -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)




(a) Confirm good connection of the hybrid vehicle control ECU connectors.
(b) Disconnect the C2 MAF meter connector.
(c) Disconnect the C64 hybrid vehicle control ECU connector.
(d) Measure the resistance.
Standard resistance:





(e) Reconnect the MAF meter connector.
(f) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
5. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)




(a) Disconnect the C2 MAF meter connector.
(b) Connect the Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Turn the tester on.
(e) Select the following menu items: Powertrain / Engine / Data List / All Data / Intake Air.
(f) Read the value displayed on the tester.
Standard value:
-40°C (-40°F)
(g) Reconnect the MAF meter connector.
OK -- REPLACE MASS AIR FLOW METER
NG -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)




(a) Disconnect the C2 MAF meter connector.
(b) Disconnect the C64 hybrid vehicle control ECU connector.
(c) Measure the resistance.
Standard resistance:





(d) Reconnect the MAF meter connector.
(e) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE HYBRID VEHICLE CONTROL ECU