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Home >> Lexus >> 2012 >> LS 460 AWD V8-4.6L (1UR-FSE) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0112

P0112





1UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P00AC, P00AD, P0112, P0113: Intake Air Temperature Sensor 1 Circuit Low Bank 2

DESCRIPTION





- The Intake Air Temperature (IAT) sensor, mounted on 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 as voltage changes (See Fig. 1).

- The IAT sensor is powered by a 5 V supply from the THA and THA2 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, according to changes in the IAT, the voltage at terminal THA and THA2 also varies. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve driveability.

HINT
When DTC P00AC, P00AD, P0112 or P0113 is 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 entering the following menus: Powertrain / Engine / Data List / All Data / Intake Air Temp B1S1 or Intake Air Temp B2S1.





MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to calculate the Intake Air Temperature (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 P00AD or 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 P00AC or 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

P00AC and P0112:





P00AD and P0113:





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG) 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 engine switch off and wait for at least 30 seconds.

5. Turn the engine switch on (IG) and turn the Techstream on [A].

6. Wait 0.5 seconds or more.

7. Enter the following menus: Powertrain / Engine / Trouble Codes.

8. Read the DTCs [B].

HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.

9. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

10. Input the DTC: P00AC, P00AD, P0112 or P0113.

11. Check the DTC judgment result.





12. If the test result is INCOMPLETE or N/A and no 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
- 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. Freeze frame data records the engine condition when malfunctions are detected. 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.
- Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
- Bank 2 refers to the bank that does not include the No. 1 cylinder.

PROCEDURE

1. READ VALUE USING TECHSTREAM (INTAKE AIR TEMPERATURE)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / All Data / Intake Air Temp B1S1 or Intake Air Temp B2S1.

(e) Read the value displayed on the Techstream.

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.

B -- READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)

C -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems
A -- Continue to next step.

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





(a) Disconnect the E13 or E22 MAF meter connector.

(b) Connect terminals THA and E2 or THAR and E2R of the MAF meter wire harness side connector.

(c) Connect the Techstream to the DLC3.

(d) Turn the engine switch on (IG).

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / Engine / Data List / All Data / Intake Air Temp B1S1 or Intake Air Temp B2S1.

(g) Read the value displayed on the Techstream.

Standard:

140°C (284°F) or higher

OK -- CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER Removal
NG -- Continue to next step.

3. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN ECM)





(a) Disconnect the E13 or E22 MAF meter connector.

(b) Connect terminals THA and E2 or THA2 and E2 of the E1 ECM connector.

HINT
Before checking, do visual and contact pressure checks on the ECM connector.

(c) Connect the Techstream to the DLC3.

(d) Turn the engine switch on (IG).

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / Engine / Data List / All Data / Intake Air Temp B1S1 or Intake Air Temp B2S1.

(g) Read the value displayed on the Techstream.

Standard:

140°C (284°F) or higher

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR

NG -- CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM Removal

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





(a) Disconnect the E13 or E22 MAF meter connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Data List / All Data / Intake Air Temp B1S1 or Intake Air Temp B2S1.

(f) Read the value displayed on the Techstream.

Standard:

-40°C (-40°F)

OK -- REPLACE MASS AIR FLOW METER Removal
NG -- Continue to next step.

5. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN ECM)





(a) Disconnect the E13 or E22 MAF meter connector.

(b) Disconnect the E1 ECM connector.

(c) Connect the Techstream to the DLC3.

(d) Turn the engine switch on (IG).

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / Engine / Data List / All Data / Intake Air Temp B1S1 or Intake Air Temp B2S1.

(g) Read the value displayed on the Techstream.

Standard:

-40°C (-40°F)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR

NG -- REPLACE ECM Removal
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