Toyota Venza: Intake Air Temperature Circuit Low Input (P0112,P0113)

Toyota Venza Service Manual / 1ar-fe Engine Control / Sfi System / Intake Air Temperature Circuit Low Input (P0112,P0113)

DESCRIPTION

The intake air temperature sensor, in the mass air flow meter, monitors the intake air temperature. The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature becomes low, the resistance of the thermistor increases. When the temperature becomes high, the resistance drops. These variations in resistance are transmitted to the ECM as voltage changes (see Fig. 1).
The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
Resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes, the voltage at terminal THA varies accordingly. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve driveability.
HINT:

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

DTC No.	DTC Detection Condition	Trouble Area
P0112	A short in intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic)	Short in intake air temperature sensor circuit Intake air temperature sensor (built into mass air flow meter) ECM
P0113	An open in intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic)	Open in intake air temperature sensor circuit Intake air temperature sensor (built into mass air flow meter) ECM

DTC No.

DTC Detection Condition

Trouble Area

P0112

A short in intake air temperature sensor circuit for 0.5 seconds

(1 trip detection logic)

Short in intake air temperature sensor circuit
Intake air temperature sensor (built into mass air flow meter)
ECM

P0113

An open in intake air temperature sensor circuit for 0.5 seconds

(1 trip detection logic)

Open in intake air temperature sensor circuit
Intake air temperature sensor (built into mass air flow meter)
ECM

HINT:

When any of these DTCs are set, check the intake air temperature by entering the following menus on the Techstream: Powertrain / Engine / Data List / Intake Air.

Temperature Displayed	Malfunction
-40°C (-40°F)	Open circuit
Higher than 128°C (262°F)	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 malfunction in the intake air temperature 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 intake air temperature 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.

MONITOR STRATEGY

Related DTCs	P0112: Intake Air Temperature Sensor Range Check (Low voltage) P0113: Intake Air Temperature Sensor Range Check (High voltage)
Required Sensors/Components (Main)	Intake air temperature sensor
Required Sensors/Components (Related)	-
Frequency of Operation	Continuous
Duration	0.5 seconds
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored	None
All of the following conditions are met	-
Battery voltage	8 V or more
Ignition switch	ON
Starter	OFF

TYPICAL MALFUNCTION THRESHOLDS

P0112

Intake air temperature sensor voltage [Intake air temperature]

Less than 0.18 V [higher than 128°C (262°F)]

P0113

Intake air temperature sensor voltage [Intake air temperature]

More than 4.91 V [Below -55°C (-67°F)]

COMPONENT OPERATING RANGE

Intake air temperature sensor voltage [Intake air temperature]

0.18 V to 4.91 V [-55 to 128°C (-67 to 262°F)]

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the Clear DTC procedure) (See page ).

Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on.
Wait 0.5 seconds or more.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the Pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P0112 or P0113.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.

If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. 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.

PROCEDURE

1.	READ VALUE USING TECHSTREAM (INTAKE AIR)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Enter the following menus: Powertrain / Engine / Data List / Intake Air.

(e) Read the value displayed on the Techstream.

Standard:

Same as actual intake air temperature.

Result	Proceed to
-40°C (-40°F)	A
Higher than 128°C (262°F)	B
Same as actual intake air temperature	C

HINT:

If there is an open circuit, the Techstream indicates -40°C (-40°F).

If there is a short circuit, the Techstream indicates higher than 128°C (262°F).

GO TO STEP 4

CHECK FOR INTERMITTENT PROBLEMS

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

(a) Confirm good connection at the mass air flow meter.

Text in Illustration

Mass Air Flow Meter

ECM

Front view of wire harness connector

(to Mass Air Flow Meter)

(b) Disconnect the mass air flow meter connector.

(d) Connect the Techstream to the DLC3.

(e) Turn the ignition switch to ON.

(f) Turn the Techstream on.

(g) Enter the following menus: Powertrain / Engine / Data List / Intake Air.

(h) Read the value displayed on the Techstream.

Standard:

Higher than 128°C (262°F)

HINT:

Perform "Inspection After Repair" after replacing the mass air flow meter (See page ).

REPLACE MASS AIR FLOW METER

3.	CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

(a) Disconnect the mass air flow meter connector.

(b) Disconnect the ECM connector.

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
B3-1 (THA) - B58-116 (THA)	Always	Below 1 Ω
B3-2 (E2) - B58-93 (ETHA)	Always	Below 1 Ω

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)

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

(a) Disconnect the mass air flow meter connector.

Text in Illustration

*1	Mass Air Flow Meter
*2	ECM

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Data List / Intake Air.

(f) Read the value displayed on the Techstream.

Standard:

-40°C (-40°F)

HINT:

Perform "Inspection After Repair" after replacing the mass air flow meter (See page ).

REPLACE MASS AIR FLOW METER

5.	CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

(a) Disconnect the mass air flow meter connector.

(b) Disconnect the ECM connector.

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
B3-1 (THA) or B58-116 (THA) - Body ground	Always	10 kΩ or higher

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)

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