P0112, P0113

DTC Code	DTC Name
P0112	Intake Air Temperature Circuit Low Input
P0113	Intake Air Temperature Circuit High Input

DESCRIPTION

The intake air temperature sensor, mounted on the mass air flow meter sub-assembly, 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 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 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, according to changes in the intake air temperature, 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 driveability.

Tech Tips

When DTC P0112 or P0113 is stored, 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.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0112	Intake Air Temperature Circuit Low Input	A short in the 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 sub-assembly) ECM	Comes on	DTC stored
P0113	Intake Air Temperature Circuit High Input	An open in the 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 sub-assembly) ECM	Comes on	DTC stored

Tech Tips

When any of these DTCs are output, check the intake air temperature using the GTS. Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / 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 circuit and stores a DTC.

Example:

If the sensor output voltage is higher 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 stores 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 stores DTC P0112.

MONITOR STRATEGY

Frequency of Operation

Continuous

CONFIRMATION DRIVING PATTERN

Turn the engine switch on (IG) and wait for 5 seconds or more.

WIRING DIAGRAM


*a	Intake Air Temperature Sensor (Built into Mass Air Flow Meter Sub-assembly)

CAUTION / NOTICE / HINT

Tech Tips

Read freeze frame data using the GTS. 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

READ VALUE USING GTS (INTAKE AIR)

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Intake Air.

Powertrain > Engine and ECT > Data List

Tester Display

Intake Air

Tester Display
Intake Air

Read the value displayed on the GTS.

OK
Same as actual intake air temperature.

Result

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

Tech Tips

If there is an open circuit, the GTS indicates -40°C (-40°F).
If there is a short circuit, the GTS indicates higher than 128°C (262°F).

B

READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS) Click here

C

CHECK FOR INTERMITTENT PROBLEMS Click here

A

READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)

Disconnect the mass air flow meter sub-assembly connector.

*1

Mass Air Flow Meter Sub-assembly

*2

ECM

*a

Front view of wire harness connector

(to Mass Air Flow Meter Sub-assembly)

-

Connect terminals 1 (THA) and 2 (E2) of the mass air flow meter sub-assembly connector on the wire harness side.
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Intake Air.

Powertrain > Engine and ECT > Data List

Tester Display

Intake Air

Tester Display
Intake Air

Read the value displayed on the GTS.

Standard value
Higher than 128°C (262°F)

Tech Tips

Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

Click here

Result

Proceed to
OK
NG

OK

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

NG

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
B1-1 (THA) - B77-93 (THA)	Always	Below 1 Ω
B1-2 (E2) - B77-94 (ETHA)	Always	Below 1 Ω

Result

Proceed to
OK
NG

OK

REPLACE ECM Click here

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)

*1 Mass Air Flow Meter Sub-assembly

*2 ECM

Disconnect the mass air flow meter sub-assembly connector.
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Intake Air.

Powertrain > Engine and ECT > Data List

Tester Display

Intake Air

Tester Display
Intake Air

Read the value displayed on the GTS.

Standard value
-40°C (-40°F)

Tech Tips

Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

Click here

Result

Proceed to
OK
NG

OK

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

NG

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
B1-1 (THA) or B77-93 (THA) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

OK

REPLACE ECM Click here

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

SFI SYSTEM(w/ Canister Pump Module), Diagnostic DTC:P0112, P0113