P0113
2AR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0112,P0113: Intake Air Temperature Circuit Low Input
DESCRIPTION
- The intake air temperature sensor, mounted on 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 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.
HINT
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.
HINT
When any of these DTCs are output, check the intake air temperature using the Techstream. Enter the following menus: Powertrain / Engine / All Data / 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 malfunction in the intake air temperature sensor and stores 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 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.
If the malfunction is not repaired successfully, a DTC is stored 0.5 seconds after the engine is next started.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P0112
P0113
COMPONENT OPERATING RANGE
CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON and turn the Techstream on.
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.
4. Turn the ignition switch off and wait for at least 30 seconds.
5. Turn the ignition switch to ON and turn the Techstream on.
6. Wait 0.5 seconds or more [A].
7. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
8. Input the DTC: P0112 or P0113.
9. Check the DTC judgment result [B].
10. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
11. Read Pending DTCs.
HINT
If a pending DTC is output, the system is malfunctioning.
12. If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.
HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.
WIRING DIAGRAM
INSPECTION PROCEDURE
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 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 (INTAKE AIR TEMPERATURE)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / All Data / Intake Air.
(e) Read the value displayed on the Techstream.
OK:
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).
C -- CHECK FOR INTERMITTENT PROBLEMS 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 1 (THA) and 2 (E2) of the mass air flow meter wire harness side connector.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine / All Data / Intake Air.
(g) Read the value displayed on the Techstream.
Standard Value:
140°C (284°F)
(h) Reconnect the mass air flow meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
OK -- REPLACE MASS AIR FLOW METER Removal
3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the mass air flow meter connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
(d) Reconnect the mass air flow meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM Removal
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 ignition switch to ON.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine / All Data / Intake Air.
(f) Read the value displayed on the Techstream.
Standard Value:
-40°C (-40°F)
(g) Reconnect the mass air flow meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
OK -- REPLACE MASS AIR FLOW METER Removal
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the mass air flow meter connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Short):
(d) Reconnect the mass air flow meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM Removal