Toyota Tundra. Manual — part 1270

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

Fig. 267: Identifying J9 Ignition Switch Connector Terminals

OK : REPAIR OR REPLACE HARNESS OR CONNECTOR

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.

Tester Connection

Switch Condition

Specified Condition

All Terminals

Ignition switch position LOCK 10 kohms or higher

2 (ACC) - 4 (AM1)

Ignition switch position ACC

Below 1 ohms

1 (IG1) - 2 (ACC) - 4 (AM1)

Ignition switch position ON

5 (AM2) - 6 (IG2)

1 (IG1) - 3 (ST1) - 4 (AM1)

Ignition switch position START

5 (AM2) - 6 (IG2) - 7 (ST2)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 268: VC Output Circuit - 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 (1GR-FE) - Tundra

Fig. 269: VC Output Circuit - Wiring Diagram (1 Of 2)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 270: VC Output Circuit - Wiring Diagram (2 Of 2)

INSPECTION PROCEDURE

1. CHECK MIL

a. Check that the Malfunction Indicator Lamp (MIL) lights up when turning the ignition switch ON.

Result

RESULT CHART

A : SYSTEM OK

B : Go to next step.

Result

Proceed To

MIL illuminates

A

MIL does not illuminate

B

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra