Inspection Procedure

NOTE:

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, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL(MASS AIR FLOW RATE)

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Start the engine.
Push the hand-held tester or the OBD II scan tool main switch ON.

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:

DESCRIPTION

Air Flow Rate (gm/s)

Proceed to

0.0

271.0 or more

Between 1.0 and 270.0 ⁽¹⁾

⁽¹⁾	The value must be changed when the throttle valve is opened or closed.

B: Go to step f
C: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
A: Go to next step.

INSPECT MASS AIR FLOW SENSOR(POWER SOURCE)

Turn the ignition switch ON.
Disconnect the M1 mass air flow sensor connector.

Measure the voltage between the terminal of the wire harness side connector and body ground.

Standard:

TESTER CONNECTIONS SPECIFIED

Tester Connection	Specified Condition
+B (M1-1) - Body ground	9 to 14 V

Reconnect the mass air flow sensor connector.

Fig 1: Identifying M1 Mass Air Flow Sensor Connector Terminal
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: Go to step 5
OK: Go to next step.

INSPECT ECM (VG VOLTAGE)

Start the engine.

Measure the voltage between the terminals of the E4 ECM connector.

NOTE:

The shift position should be P or N and the A/C switch should be turned OFF.

Standard:

TESTER CONNECTION'S SPECIFIED CONDITION

Tester Connection	Condition	Specified Condition
VG (E4-24) - EVG (E4-32)	Engine is idling	1.1 to 1.5 V

Fig 2: Identifying E4 ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: REPLACE ECM (See REPLACEMENT )
NG: Go to next step.

CHECK HARNESS AND CONNECTOR(MASS AIR FLOW SENSOR - ECM)

Disconnect the M1 mass air flow sensor connector.
Disconnect the E4 ECM connector.

Check the resistance between the wire harness side connectors.

Standard (Check for open):

TESTER CONNECTION'S SPECIFIED CONDITION

Tester Connection	Specified Condition
VG (M1-3) - VG (E4-24)	Below 1 Ω
E2G (M1-2) - EVG (E4-32)	Below 1 Ω

Fig 3: Identifying M1 Mass Air Flow Sensor Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard (Check for short):

TESTER CONNECTION'S SPECIFIED CONDITION

Tester Connection	Specified Condition
VG (M1-3) or VG (E4-24) - Body ground	10 kΩ or higher

Reconnect the mass air flow sensor connector.
Reconnect the ECM connector.

Fig 4: Identifying E4 ECM Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE MASS AIR FLOW SENSOR

CHECK HARNESS AND CONNECTOR(MASS AIR FLOW SENSOR - EFI RELAY)

Remove the EFI relay from the engine room R/B.
Disconnect the M1 mass air flow sensor connector.

Check the resistance between the wire harness side connectors.

Standard (Check for open):

TESTER CONNECTION'S SPECIFIED CONDITIONS

Tester Connection	Specified Condition
+B (M1-1) - EFI relay (3)	Below 1 Ω

Fig 5: Identifying EFI Relay Connector Terminals In Engine Room R/B

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard (Check for short):

TESTER CONNECTION'S SPECIFIED CONDITIONS

Tester Connection	Specified Condition
+B (M1-1) or EFI relay (3) - Body ground	10 kΩ or higher

Reconnect the mass air flow sensor connector.
Reinstall the EFI relay.

Fig 6: Identifying M1 Mass Air Flow Sensor Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: CHECK FOR ECM POWER SOURCE CIRCUIT (See ECM POWER SOURCE CIRCUIT )

INSPECT ECM (SENSOR GROUND)

Check the resistance between the terminals of the E4 ECM connector.

Standard:

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
EVG (E4-32) - Body ground	Below 1 Ω

Fig 7: Identifying E4 ECM Connector Terminals

NG: REPLACE ECM (See REPLACEMENT )
OK: Go to next step.

CHECK HARNESS AND CONNECTOR(MASS AIR FLOW SENSOR - ECM)

Disconnect the M1 mass air flow sensor connector.
Disconnect the E4 ECM connector.

Check the resistance between the wire harness side connectors.

Standard (Check for open):

Fig 8: Tester Connection's Specified Condition Table (Check For Open)

Fig 9: Identifying M1 Mass Air Flow Sensor Connector Terminals

Standard (Check for short):

TESTER CONNECTION'S SPECIFIED CONDITION

Tester Connection	Specified Condition
VG (M1-3) or VG (E4-24) - Body ground	10 kΩ or higher

Reconnect the ECM connector.
Reconnect the mass air flow sensor connector.

Fig 10: Identifying E4 ECM Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE MASS AIR FLOW SENSOR