Inspection Procedure

HINT:

• If other DTCs relating 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 intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.

1. READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (INTAKE AIR TEMPERATURE) 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the tester ON.
   4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   5. Read the value displayed on the tester.

   Standard: 

   Same as actual Intake Air Temperature (IAT). 

   Result 

   INTAKE AIR TEMPERATURE
   
   

   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, the intelligent tester indicates - 40°C (-40°F).
   • If there is a short circuit, the intelligent tester indicates 140°C (284°F) or higher.

   B : GO TO STEP   4 

   C : CHECK FOR INTERMITTENT PROBLEMS 

   A : Go to next step 

2. READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN WIRE HARNESS) 
   1. Disconnect the M1 Mass Air Flow (MAF) meter connector.
   2. Connect terminals THA and E2 of the MAF meter wire harness side connector.
   3. Connect the intelligent tester to the DLC3.
   4. Turn the ignition switch ON.
   5. Turn the tester ON.
   6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   7. Read the value displayed on the tester.

      Standard: 140°C (284°F) or higher 

   8. Reconnect the MAF meter connector.
   Fig 1: Chekcing For Open In Wire Harness
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER 

   NG : Go to next step 

3. READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN ECM) 
   1. Disconnect the M1 MAF meter connector.
   2. Connect terminals THA and E2 of the E8 ECM connector.

      HINT:

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

   3. Connect the intelligent tester to the DLC3.
   4. Turn the ignition switch ON.
   5. Turn the tester ON.
   6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   7. Read the value displayed on the tester.

      Standard: 140°C (284°F) or higher 

   8. Reconnect the MAF meter connector.
   Fig 2: Checking For Open in ECM
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG : CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM 

4. READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the M1 MAF meter connector.
   2. Connect the intelligent tester to the DLC3.
   3. Turn the ignition switch ON.
   4. Turn the tester ON.
   5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / 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: Checking For Short In Wire Harness
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : REPLACE MASS AIR FLOW METER 

   NG : Go to next step 

5. READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN ECM) 
   1. Disconnect the E8 ECM connector.
   2. Connect the intelligent tester to the DLC3.
   3. Turn the ignition switch ON.
   4. Turn the tester ON.
   5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   6. Read the value displayed on the tester.

      Standard: -40°C (-40°F) or higher 

   7. Reconnect the ECM connector.
   Fig 4: Checking For Short In ECM
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG : REPLACE ECM