P00AC, P00AD, P0112, P0113

DTC Code	DTC Name
P00AC	Intake Air Temperature Sensor 1 Circuit Low Bank 2
P00AD	Intake Air Temperature Sensor 1 Circuit High Bank 2
P0112	Intake Air Temperature Circuit Low Input
P0113	Intake Air Temperature Circuit High Input

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 drivability.

Tech Tips

When any of 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.

DTC No.	DTC Detection Condition	Trouble Area
P00AC	Short in Intake Air Temperature (IAT) sensor 2 circuit for 0.5 seconds (1 trip detection logic)	Short in IAT sensor 2 circuit IAT sensor 2 (built into MAF meter) ECM
P00AD	Open in Intake Air Temperature (IAT) sensor 2 circuit for 0.5 seconds (1 trip detection logic)	Open in IAT sensor 2 circuit IAT sensor 2 (built into MAF meter) ECM
P0112	Short in Intake Air Temperature (IAT) sensor 1 circuit for 0.5 seconds (1 trip detection logic)	Short in IAT sensor 1 circuit IAT sensor 1 (built into MAF meter) ECM
P0113	Open in Intake Air Temperature (IAT) sensor 1 circuit for 0.5 seconds (1 trip detection logic)	Open in IAT sensor 1 circuit IAT sensor 1 (built into MAF meter) ECM

Tech Tips

When any of these DTCs are set, check the IAT by entering the following menus on the GTS: Powertrain / Engine / Data List / Intake Air Temp B1S1 or Intake Air Temp B2S1.

Temperature Displayed	Malfunction
-40°C (-40°F)	Open circuit
140°C (284°F) or higher	Short circuit

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 is less than -40°C (-40°F) 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 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 P00AC or P0112.

If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.

WIRING DIAGRAM


*a	IAT Sensor (Built into MAF Meter for Bank 1)
*b	THAR
*c	IAT Sensor (Built into MAF Meter for Bank 2)

CAUTION / NOTICE / HINT

Tech Tips

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 GTS. Freeze frame data records the engine conditions 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.

PROCEDURE

READ VALUE USING GTS (INTAKE AIR TEMPERATURE)

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Data List / Intake Air Temp B1S1 or Intake Air Temp B2S1.

Read the value displayed on the GTS.

Standard
Same as actual Intake Air Temperature (IAT).

Result

Temperature Displayed	Proceed to
-40°C (-40°F)	A
140°C (284°F) or higher	B
Same as actual IAT	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 140°C (284°F) or higher.

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)
1. Disconnect the E13 or E22 MAF meter connector.
2. Connect terminals THA and E2 or THAR and E2R of the MAF meter wire harness side connector.
3. Connect the GTS to the DLC3.
4. Turn the engine switch on (IG).
5. Turn the GTS on.
6. Enter the following menus: Powertrain / Engine / Data List / Intake Air Temp B1S1 or Intake Air Temp B2S1.
7. Read the value displayed on the GTS.
  
  Standard
  
  140°C (284°F) or higher
OK
CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER Click here

NG
READ VALUE USING GTS (CHECK FOR OPEN IN ECM)
1. Disconnect the E13 or E22 MAF meter connector.
2. Connect terminals THA and E2 or THA2 and E2 of the E1 ECM connector.
  
  Tech Tips
  
  Before checking, do visual and contact pressure checks on the ECM connector.
3. Connect the GTS to the DLC3.
4. Turn the engine switch on (IG).
5. Turn the GTS on.
6. Enter the following menus: Powertrain / Engine / Data List / Intake Air Temp B1S1 or Intake Air Temp B2S1.
7. Read the value displayed on the GTS.
  
  Standard
  
  140°C (284°F) or higher
NG
CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM Click here

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR
READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the E13 or E22 MAF meter connector.
2. Connect the GTS to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the GTS on.
5. Enter the following menus: Powertrain / Engine / Data List / Intake Air Temp B1S1 or Intake Air Temp B2S1.
6. Read the value displayed on the GTS.
  
  Standard
  
  -40°C (-40°F)
OK
REPLACE MASS AIR FLOW METER Click here

NG
READ VALUE USING GTS (CHECK FOR SHORT IN ECM)
1. Disconnect the E13 or E22 MAF meter connector.
2. Disconnect the E1 ECM connector.
3. Connect the GTS to the DLC3.
4. Turn the engine switch on (IG).
5. Turn the GTS on.
6. Enter the following menus: Powertrain / Engine / Data List / Intake Air Temp B1S1 or Intake Air Temp B2S1.
7. Read the value displayed on the GTS.
  
  Standard
  
  -40°C (-40°F)
NG
REPLACE ECM Click here

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR

SFI SYSTEM, Diagnostic DTC:P00AC, P00AD, P0112, P0113