Inspection Procedure

HINT:

If DTCs that are related to different systems are output simultaneously while terminal E2 is used as a ground terminal, 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, 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 (INTAKE AIR TEMPERATURE)

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON. Push the hand-held tester or the OBD II scan tool tester main switch ON.
On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.

Temperature: The same as actual intake air temperature

Result:

INTAKE AIR TEMPERATURE RESULT TABLE

Display	Proceed to
-40°C (-40°F)	A
140°C (284°F) or more	B
OK (same as present temperature)	C

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 4

C: CHECK FOR INTERMITTENT PROBLEMS

A: Go to next step

READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN HARNESS)
1. Disconnect the M1 MAF meter connector.
2. Connect terminals THA and E2 of the M1 MAF meter wire harness side connector.
3. Turn the ignition switch ON.
4. On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
OK: Temperature value: 140°C (284°F) or more

Fig 1: Identifying M1 MAF Meter Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK: REPLACE MASS AIR FLOW METER (IAT SENSOR)

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 MAF meter connector.
2. Connect terminals THA and E2 of the E10 and E9 ECM connector.
  HINT:
  
  Before checking, do a visual and contact pressure check for the ECM connector.
3. Turn the ignition switch ON.
4. On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
OK: Temperature value: 140°C (284°F) or more

Fig 2: Connecting Terminals THA And E2 ECM Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig 3: Identifying ECM Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK: REPAIR OR REPLACE HARNESS AND CONNECTOR

NG: Go to next step

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM (See ECM (2AZ-FE) )
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN HARNESS)
1. Disconnect the M1 MAF meter connector.
2. Turn the ignition switch ON.
3. On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
OK: Temperature value: -40°C (-40°F)

OK: REPLACE MASS AIR FLOW METER (INTAKE AIR TEMPERATURE SENSOR)

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 and E9 ECM connector.
2. Turn the ignition switch ON.
3. On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.
OK: Temperature value: -40°C (-40°F)

Fig 5: Disconnecting M1 MAF Meter Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig 6: Disconnecting ECM Connectors
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK: REPAIR OR REPLACE HARNESS AND CONNECTOR

NG: REPLACE ECM (See ECM (2AZ-FE) )