Toyota Tundra. Manual — part 1638

b. Measure the resistance according to the value (s) in the table below.

Standard resistance

RESISTANCE SPECIFIED CONDITIONS

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

4. INSPECT ECM (IGSW VOLTAGE)

a. Disconnect the A24 and D74 ECM connectors.

Fig. 294: Identifying A24 And D74 ECM Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Turn the ignition switch to ON.

c. Measure the voltage according to the value (s) in the table below.

Standard voltage

VOLTAGE SPECIFIED CONDITION

NG: Go to step 5

OK: REPLACE ECM (See REMOVAL )

Tester Connection

Condition Specified Condition

D74-81 (E1) - Body ground Always

Below 1 ohms

Tester Connection

Switch Condition Specified Condition

A24-28 (IGSW) - D74-81 (E1) Ignition switch ON

11 to 14 V

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

Saturday, June 19, 2010 7:34:48 PM

Page 645

© 2006 Mitchell Repair Information Company, LLC.

5. CHECK HARNESS AND CONNECTOR (RELAY BLOCK - ECM, IGNITION SWITCH,

BATTERY AND BODY GROUND)

a. Disconnect the A24 ECM connector.

b. Disconnect the J9 ignition switch connector.

Fig. 295: Identifying A24 ECM And J9 Ignition Switch Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

c. Disconnect the cable from the battery positive (+) terminal.

d. Remove the AM2 fuse and integration relay.

e. Measure the resistance according to the value (s) in the table below.

Standard resistance

RESISTANCE SPECIFIED CONDITIONS

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Tester Connection

Condition Specified Condition

A24-28 (IGSW) - 1B-8

Always

Below 1 ohms

1B-7 - Body ground

Always

Below 1 ohms

Positive (+) battery cable -1C-1

Always

Below 1 ohms

Positive (+) battery cable - AM2 fuse terminal 1

Always

Below 1 ohms

J9-5 (AM2) - AM2 fuse terminal 2

Always

Below 1 ohms

J9-6 (IG2) - 1B-6

Always

Below 1ohms

A24-28 (IGSW) - 1B-8 - Body ground

Always

10 kohms or higher

Positive (+) battery cable or AM2 fuse terminal 1 - Body ground Always

10 kohms or higher

Positive (+) battery cable or 1C-1 - Body ground

Always

10 kohms or higher

J9-5 (AM2) or AM2 fuse terminal 2 - Body ground

Always

10 kohms or higher

J9-6 (IG2) or 1B-6-Body ground

Always

10 kohms or higher

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

Saturday, June 19, 2010 7:34:48 PM

Page 646

© 2006 Mitchell Repair Information Company, LLC.

OK: Go to Next Step

6. INSPECT IGNITION SWITCH (See INSPECTION PROCEDURE )

NG: REPLACE IGNITION SWITCH (See REMOVAL )

OK: Go to Next Step

7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, BATTERY AND

BODY GROUND)

a. Disconnect the A24 ECM connector.

b. Disconnect the cable from the battery positive terminal.

c. Remove the integration relay from the engine room relay block.

d. Disconnect the integration relay connector.

Fig. 296: Identifying A24 ECM And Integration Relay Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

e. Measure the resistance according to the value (s) in the table below.

Standard resistance

RESISTANCE SPECIFIED CONDITIONS

Tester Connection

Condition Specified Condition

A24-3 (+B) - 1B-4

Always

Below 1 ohms

A24-2 (+B2) - 1B-4

Always

Below 1 ohms

A24-34 (MREL) - 1B-2

Always

Below 1 ohms

1C-1 - Positive (+) battery cable

Always

Below 1 ohms

1B-3 - Body ground

Always

Below 1 ohms

A24-3 (+B) or 1B-4-Body ground

Always

10 kohms or higher

A24-2 (+B2) or 1B-4-Body ground

Always

10 kohms or higher

A24-34 (MREL) or 1B-2-Body ground

Always

10 kohms or higher

1C-1 or Positive (+) battery cable - Body ground Always

10 kohms or higher

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

Saturday, June 19, 2010 7:34:48 PM

Page 647

© 2006 Mitchell Repair Information Company, LLC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPAIR OR REPLACE ENGINE ROOM RELAY BLOCK

VC OUTPUT CIRCUIT

DESCRIPTION

The ECM constantly generates 5 V power from the battery voltages supplied to the +B (BATT) terminal to
operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

Fig. 297: VC Output Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power
through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this
condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.

HINT:

Under normal conditions, the MIL is illuminated for several seconds when the ignition switch is first turned
ON. The MIL goes off when the engine is started.

WIRING DIAGRAM

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

Saturday, June 19, 2010 7:34:48 PM

Page 648

© 2006 Mitchell Repair Information Company, LLC.