Inspection Procedure

HINT:

Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.

READ VALUE OF HAND-HELD TESTER (INTAKE AIR TEMPERATURE)
1. Connect the hand-held tester to the DLC3.
2. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR.
3. Read the INTAKE AIR.
Standard: Same value as the actual IAT.

Result:

Fig 1: Result Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:
- If there is an open circuit, the hand-held tester indicates -40°C (-40°F).
- If there is a short circuit, the hand-held tester indicates 140°C (284°F) or more.
1. B: Go to step 4
2. C: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
3. A: Go to next step.
READ VALUE OF HAND-HELD TESTER (CHECK FOR OPEN IN WIRE HARNESS)
1. Disconnect the M1 MAF sensor connector.
2. Connect terminals THA and ETHA of the MAF sensor wire harness side connector.
3. Turn the ignition switch ON.
4. Read the INTAKE AIR.
  Standard: 140°C (284°F) or more
5. Reconnect the MAF sensor connector.
  
  Fig 2: Checking Open In Wire Harness (1 Of 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 3: Checking Open In Wire Harness (2 Of 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPLACE MAF SENSOR
2. NG: Go to next step.
READ VALUE OF HAND-HELD TESTER (CHECK FOR OPEN IN ECM)
1. Disconnect the M1 MAF sensor connector.
2. Connect terminals THA and ETHA of the E4 ECM connector.
  HINT:
  
  Before checking, do a visual and contact pressure check for the ECM connector.
3. Turn the ignition switch ON.
4. Read the INTAKE AIR.
  
  Fig 4: Checking For Open In ECM (1 Of 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard: 140°C (284°F) or more
5. Reconnect the MAF sensor connector.
Fig 5: Checking For Open In ECM (2 Of 2)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
2. OK: Go to next step.
  REPLACE MAF SENSOR
READ VALUE OF HAND-HELD TESTER (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the M1 MAF sensor connector.
2. Turn the ignition switch ON.
3. Read the INTAKE AIR.
  Standard: -40°C (-40°F)
4. Reconnect the MAF sensor connector.
  
  Fig 6: Checking For Sort In Wire Harness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPLACE MAF SENSOR
2. NG: Go to next step.
READ VALUE OF HAND-HELD TESTER (CHECK FOR SHORT IN HARNESS OR ECM)
1. Disconnect the M1 MAF sensor connector.
2. Disconnect the E4 and E5 ECM connector.
3. Turn the ignition switch ON.
4. Read the INTAKE AIR.
  Standard: -40°C (-40°F)
5. Reconnect the ECM connector.
6. Reconnect the MAF sensor connector.
  
  Fig 7: Checking For Short In Harness Or ECM (1 Of 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 8: Checking For Short In Harness Or ECM (2 Of 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPLACE ECM (See REPLACEMENT )
2. OK: Go to next step.
  REPAIR OR REPLACE HARNESS AND CONNECTOR