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: 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, 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 OR OBD II SCAN TOOL (MASS AIR FLOW RATE)
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Start the engine.
3. Turn the hand-held tester or the OBD II scan tool ON.
4. Select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF and read its value displayed on the hand-held tester or the OBD II scan tool.
  Result:
  
  Fig 1: Air Flow Rate Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
B: Go to step 6

C: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )

A: GO TO NEXT STEP.
INSPECT MASS AIR FLOW METER (POWER SOURCE)
1. Turn the ignition switch to ON.
2. Disconnect the M1 mass air flow meter connector.
3. Measure the voltage between the terminal of the wire harness side connector and the body ground.
  Standard:
  
  Fig 2: Mass Air Flow Meter Terminals Specified Condition Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the mass air flow meter connector.
  
  Fig 3: Identifying Mass Air Flow Meter Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: Go to step 4

OK: GO TO NEXT STEP.
INSPECT ECM (VG VOLTAGE)
1. Start the engine.
2. Measure the voltage between the specified terminals of the E10 ECM connector.
  
  Fig 4: Identifying ECM Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT: The shift position should be P or N and the A/C switch should be turned OFF.

Standard:

Fig 5: ECM Connector Terminals Specified Condition Table
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

NG: GO TO NEXT STEP.
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
1. Disconnect the M1 mass air flow meter connector.
2. Disconnect the E10 ECM connector.
3. Check the resistance between the wire harness side connectors.
  Standard (Check for open):
  
  Fig 6: Mass Air Flow Meter Connector Terminals Specified Condition (Check For Open)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard (Check for short):
  
  Fig 7: Mass Air Flow Meter Connector Terminals Specified Condition (Check For Short)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the mass air flow meter connector.
5. Reconnect the ECM connector.
  
  Fig 8: Identifying Mass Air Flow Meter Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 9: Identifying ECM Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO NEXT STEP.

REPLACE MASS AIR FLOW METER
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI RELAY)
1. Disconnect the M1 mass air flow meter connector.
2. Remove the EFI relay from the engine room J/B.
3. Check the resistance between the wire harness side connectors.
  Standard (Check for open):
  
  Fig 10: Mass Air Flow Meter - EFI Relay Terminals Specified Condition Chart (Check For Open)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard (Check for short):
  
  Fig 11: Mass Air Flow Meter - EFI Relay Terminals Specified Condition Chart (Check For Short)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the mass air flow meter connector.
5. Reinstall the EFI relay.
  
  Fig 12: Identifying Mass Air Flow Meter Connectors
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 13: Identifying EFI Relay
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO NEXT STEP.

INSPECT ECM POWER SOURCE CIRCUIT (See INSPECTION PROCEDURE )
INSPECT ECM (SENSOR GROUND)
1. Check the resistance between the specified terminal of the E10 ECM connector and the body ground.
  Standard:
  
  Fig 14: ECM Connector Terminals Specified Condition Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 15: Identifying ECM Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE ECM (See ECM (3MZ-FE) )

OK: GO TO NEXT STEP.
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
1. Disconnect the M1 mass air flow meter connector.
2. Disconnect the E10 ECM connector.
3. Check the resistance between the wire harness side connectors.
  Standard (Check for open):
  
  Fig 16: Mass Air Flow Meter And ECM Terminals Specified Condition Chart (Check For Open)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard (Check for short):
  
  Fig 17: Mass Air Flow Meter And ECM Terminals Specified Condition Chart (Check For Short)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the mass air flow meter connector.
5. Reconnect the ECM connector.
  
  Fig 18: Identifying Mass Air Flow Meter Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 19: Connecting E10 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO NEXT STEP.

REPLACE MASS AIR FLOW METER