Toyota Tundra. Manual — part 1449

Fig. 282: Identifying A24 ECM & J9 Ignition Switch Connector With AM2 Fuse

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go to Next Step

6. INSPECT IGNITION SWITCH (See INSPECTION PROCEDURE )

NG : REPLACE IGNITION SWITCH . (See IGNITION SWITCH ).

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.

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION

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

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Fig. 283: Identifying A24 ECM Connector & Integration Relay

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.

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Fig. 284: VC Output Circuit Diagram

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

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra