Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If DTCs related 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 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)
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
3. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
  Temperature: Same value as the ambient air temperature.
  
  Result:
  
  Fig 1: Intake Air Temperature Result Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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 2

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 meter connector.
2. Connect terminals THA and E2 of the mass air flow meter wire harness side connector.
3. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
4. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
  Temperature: 140°C (284°F) or more
5. Reconnect the mass air flow meter connector.
  
  Fig 2: Connecting Terminals THA And E2 Of Mass Air Flow Meter Wire Harness Side Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 3: Identifying Mass Air Flow Meter Wire Harness Side Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE MASS AIR FLOW METER

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 meter connector.
2. Connect terminals THA and E2 of the E10 ECM connector.
  HINT: Before checking, do a visual and contact pressure check on the ECM connector.
3. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
4. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
  Temperature: 140°C (284°F) or more
5. Reconnect the mass air flow meter connector.
  
  Fig 4: Connecting Terminals THA And E2 Of E10 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Identifying ECM Connectors
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPAIR OR REPLACE HARNESS OR CONNECTOR

NG: GO TO NEXT STEP.

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM (See ECM (3MZ-FE) )
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the M1 mass air flow meter connector.
2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
3. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
  Temperature: -40°C (-40°F)
4. Reconnect the mass air flow meter connector.
  
  Fig 6: Disconnecting M1 Mass Air Flow Meter Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPLACE MASS AIR FLOW METER

NG: GO TO NEXT STEP.
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN ECM)
1. Disconnect the E10 ECM connector.
2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
3. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
  Temperature: -40°C (-40°F)
4. Reconnect the ECM connector.
  
  Fig 7: Disconnecting E10 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 8: Connecting E10 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPAIR OR REPLACE HARNESS OR CONNECTOR

NG: GO TO NEXT STEP.

REPLACE ECM (See ECM (3MZ-FE) )