Inspection Procedure

HINT:

If different DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may be open.
Read freeze frame data using the hand held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

READ VALUE OF hand held TESTER OR OBD II SCAN TOOL (INTAKE AIR TEMPERATURE)

Connect the hand held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON and push the hand held tester or the OBD II scan tool main switch ON.

Select the item "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR" and read its value displayed on the hand held tester or the OBD II scan tool.

Temperature value: Same value as the actual intake air temperature.

Result:

TEMPERATURE DISPLAY SPECIFICATION

Temperature Displayed	Proceed to
-40 °C (-40°F)	A
140°C (284°F) or more	B
OK (Same as air temperature near to the intake)	C

HINT:

If there is an open circuit, the hand held tester or the OBD II scan tool indicates -40°C (-40°F).
If there is a short circuit, the hand held tester or the OBD II scan tool indicates 140°C (284°F) or more.

B: Go to step 4
C: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
A: Go to next step.

READ VALUE OF hand held TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN WIRE HARNESS)
1. Disconnect the M1 mass air flow sensor connector.
2. Connect terminals THA and E2 of the mass air flow sensor wire harness side connector.
3. Turn the ignition switch ON.
4. Select the item "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR" and read its value displayed on the hand held tester or the OBD II scan tool.
  Temperature value: 140°C (284°F) or more
5. Reconnect the mass air flow sensor connector.
  
  Fig 1: Checking For Open In Wire Harness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Identifying Mass Air Flow Sensor Connector M1
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE MASS AIR FLOW SENSOR
2. NG: Go to next step.
READ VALUE OF hand held TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN ECM)
1. Disconnect the M1 mass air flow sensor connector.
2. Connect the terminals THA and E2 of the E3 ECM connector.
  HINT:
  
  Before checking, do a visual and contact pressure check on the ECM connector.
3. Turn the ignition switch ON.
4. Select the item "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR" and read its value displayed on the hand held tester or the OBD II scan tool.
  Temperature value: 140°C (284°F) or more
  
  Fig 3: Checking For Open In ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Reconnect the mass air flow sensor connector.
  
  Fig 4: Identifying ECM Connector E3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. NG: CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM (See REPLACEMENT )
READ VALUE OF hand held TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the M1 mass air flow sensor connector.
2. Turn the ignition switch ON.
3. Select the item "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR" and read its value displayed on the hand held tester or the OBD II scan tool.
  Temperature value: -40°C (-40°F)
4. Reconnect the mass air flow sensor connector.
  
  Fig 5: Checking For Short In Wire Harness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPLACE MASS AIR FLOW SENSOR
2. NG: Go to next step.
READ VALUE OF hand held TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN ECM)
1. Disconnect the M1 mass air flow sensor connector.
2. Disconnect the E3 ECM connector.
3. Turn the ignition switch ON.
4. Select the item "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR" and read its value displayed on the hand held tester or the OBD II scan tool.
  Temperature value: -40°C (-40°F)
5. Reconnect the ECM connector.
6. Reconnect the mass air flow sensor connector.
  
  Fig 6: Checking For Short In ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 7: Identifying ECM Connector E3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. NG: REPLACE ECM (See REPLACEMENT )