Inspection Procedure

NOTE:

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 OBDII 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, as well as other data from the time when a malfunction occurred.

Connect OBD II scan tool or hand-held tester, and read value of intake air temperature.

PREPARATION:

Connect the OBD II scan tool or the hand-held tester to the DLC3.
Turn the ignition switch ON and push the OBD II scan tool or the hand-held tester main switch ON.
When using hand-held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST/ALL/INTAKE AIR.

CHECK:

Read the temperature value on the OBD II scan tool or the hand-held tester.

OK:

Same as actual intake air temperature.

RESULT:

TEMPERATURE DISPLAY

Displayed Temperature	Proceed to
-40 °C (-40° F)	A
140°C (284° F) or more	B
OK (Same as present temperature)	C

NOTE:

If there is an open circuit, the OBD II scan tool or the hand-held tester indicates -40°C(-40 °F).
If there is a short circuit, the OBD II scan tool or the hand-held tester indicates 140°C (284°F) or more.

B: Go to step 4 .
C: Check for intermittent problems (See PRE-CHECK ).
A: Go to next step.

Check for open in harness or ECM.
PREPARATION:
1. Disconnect the M1 mass air flow meter connector.
  
  Fig 1: Disconnecting Mass Air Flow Meter Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect terminals 1 and 2 of the mass air flow meter wire harness side connector.
3. Turn the ignition switch ON.
4. When using hand-held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR.
CHECK:

Read the temperature value on the OBD II scan tool or the hand-held tester.

OK:

Temperature value: 140° C (284° F) or more
1. OK: Confirm good connection at sensor. If OK, replace mass air flow meter.
2. NG: Go to next step.
Check for open in harness or ECM.
PREPARATION:
1. Connect terminals THA and E2 of the E8 ECM connector.
  
  Fig 2: Connecting Terminal THA & E2 Of E8 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  NOTE: Before checking, do a visual and contact pressure check for the ECM connector.
2. Turn the ignition switch ON.
3. When using hand-held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR.
CHECK:

Read the temperature value on the OBD II scan tool or the hand-held tester.

OK:

Temperature value: 140° C (284° F) or more
1. OK: Repair or replace harness or connector.
2. NG: Confirm good connection at ECM. If OK, replace ECM (See INSPECTION ).
Check for short in harness and ECM.
PREPARATION:
1. Disconnect the M1 mass air flow meter connector.
2. Turn the ignition switch ON.
3. When using hand-held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR.
CHECK:

Read the temperature value on the OBD II scan tool or the hand-held tester.

OK:

Temperature value: -40° C (-40° F)
1. OK: Replace mass air flow meter.
2. NG: Go to next step.
Check for short in harness or ECM.
PREPARATION:
1. Disconnect the E8 ECM connector.
  
  Fig 4: Disconnecting E8 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch ON.
3. When using hand-held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR.
CHECK:

Read the temperature value on the OBD II scan tool or the hand-held tester.

OK:

Temperature value: -40° C (-40° F)
1. OK: Repair or replace harness or connector.
2. NG: Replace ECM (See INSPECTION ).