Inspection Procedure

HINT:

Read freeze frame data using Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction (See FREEZE FRAME DATA ).

1. READ VALUE OF INTAKE AIR TEMPERATURE SENSOR (INTAKE AIR) 
   1. Connect Techstream to the DLC3.
   2. Turn the engine switch on (IG).
   3. Turn the tester on.
   4. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
   5. Read the value displayed on the tester.

      Standard: 

      Same as actual Intake Air Temperature (IAT). 

      Result 

      RESULT REFERENCE CHART
      
      

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

      HINT:

      • If there is an open circuit, Techstream indicates -40°C (-40°F).
      • If there is a short circuit, Techstream indicates 140°C (284°F) or higher.

   B:  Go to step  4

   C: CHECK FOR INTERMITTENT PROBLEMS 

   A: Go to next step 

2. CHECK INTAKE AIR TEMPERATURE SENSOR (CHECK FOR OPEN IN SENSOR) 
   1. Confirm good connection of Mass Air Flow (MAF) meter.
   2. Disconnect the E29 MAF meter connector.
   3. Connect terminals THA and E2 of the MAF meter wire harness side connector.
   4. Connect Techstream to the DLC3.
   5. Turn the engine switch on (IG).
   6. Turn the tester on.
   7. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
   8. Read the value displayed on the tester.

      Standard: 

      140°C (284°F) or higher 

   9. Reconnect the MAF meter connector.
   Fig 1: Identifying Terminals Of E29 MAF Meter Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE MASS AIR FLOW METER 

   NG: Go to next step 

3. CHECK ECM (CHECK FOR OPEN IN ECM) 
   1. Confirm good connection of the ECM.
   2. Disconnect the E29 MAF meter connector.
   3. Connect terminals THA and ETHA of the E5 ECM connector.

      HINT:

      Before checking, do visual and contact pressure checks on the ECM connector.

   4. Connect Techstream to the DLC3.
   5. Turn the engine switch on (IG).
   6. Turn the tester on.
   7. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
   8. Read the value displayed on the tester.

      Standard: 

      140°C (284°F) or higher 

   9. Reconnect the MAF meter connector.
   Fig 2: Identifying Terminals Of E5 ECM Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG: REPLACE ECM 

4. CHECK INTAKE AIR TEMPERATURE SENSOR (CHECK FOR SHORT IN SENSOR) 
   1. Disconnect the E29 MAF meter connector.
   2. Connect Techstream to the DLC3.
   3. Turn the engine switch on (IG).
   4. Turn the tester on.
   5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
   6. Read the value displayed on the tester.

      Standard: 

      -40°C (-40°F) or higher 

   7. Reconnect the MAF meter connector.
   Fig 3: Identifying E29 MAF Meter Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE MASS AIR FLOW METER 

   NG: Go to next step 

5. CHECK ECM (CHECK FOR SHORT IN ECM) 
   1. Disconnect the E5 ECM connector.
   2. Connect Techstream to the DLC3.
   3. Turn the engine switch on (IG).
   4. Turn the tester on.
   5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
   6. Read the value displayed on the tester.

      Standard: 

      -40°C (-40°F) or higher 

   7. Reconnect the ECM connector.
   Fig 4: Identifying Terminals Of E5 ECM Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG: REPLACE ECM