P0113
3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0112: Intake Air Temperature Circuit Low Input
DTC P0112 - Intake Air Temperature Circuit Low Input
DTC P0113 - Intake Air Temperature Circuit High Input
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 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 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 also varies according to changes in the intake air temperature. 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 intake air temperature 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 intake air temperature by entering the following menus on the Techstream: Powertrain / Engine and ECT / Data List / Intake Air.
MONITOR DESCRIPTION
The ECM (included in the hybrid vehicle control ECU) 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 -40°C (-40°F) 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 more than 140°C (284°F) 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
P0112:
P0113:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
- If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
PROCEDURE
1. READ VALUE USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(e) Read the value displayed on the Techstream.
Standard:
Same as actual intake air temperature.
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.
2. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS)
(a) Disconnect the mass air flow meter connector.
(b) Connect terminals THA and E2 of the mass air flow meter wire harness side connector.
(c) Connect the Techstream to the DLC3.
(d) Turn the power switch on (IG).
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(g) Read the value displayed on the Techstream.
Standard:
140°C (284°F) or higher
(h) Reconnect the mass air flow meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE MASS AIR FLOW METER
3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the mass air flow meter connector.
(b) Disconnect the hybrid vehicle control ECU.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
Check for open
Check for short
(d) Reconnect the mass air flow meter connector.
(e) Reconnect the hybrid vehicle control ECU.
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)
(a) Disconnect the mass air flow meter connector.
(b) Connect the Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(f) Read the value displayed on the Techstream.
Standard:
-40°C (-40°F) or higher
(g) Reconnect the mass air flow meter connector.
NG -- READ VALUE USING TECHSTREAM
OK -- REPLACE MASS AIR FLOW METER
5. READ VALUE USING TECHSTREAM
(a) Disconnect the mass air flow meter connector.
(b) Disconnect the hybrid vehicle control ECU connector.
(c) Connect the Techstream to the DLC3.
(d) Turn the power switch on (IG).
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
(g) Read the value displayed on the Techstream.
Standard:
-40°C (-40°F) or higher
(h) Reconnect the mass air flow meter connector.
(i) Reconnect the hybrid vehicle control ECU connector.
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)