Toyota Tundra. Manual — part 1458

Fig. 310: Identifying D35 PNP Switch & D74 ECM Connectors

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : REPLACE ECM (See REMOVAL )

ACIS CONTROL CIRCUIT

DESCRIPTION

This circuit opens and closes the Intake Air Control Valve (IACV) in response to the engine load in order to
increase the intake efficiency (ACIS: Acoustic Control Induction System).

When the engine speed is 4200 RPM or more and the throttle valve opening angle is 60° or more, the IACV is
open (VSV: OFF). At all other times, the IACV is closed (VSV: ON).

2008 Toyota Tundra

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

Fig. 311: Identifying Intake Air Control Valve

WIRING DIAGRAM

Fig. 312: ACIS Control - Wiring Diagram

INSPECTION PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE VSV FOR ACIS)

a. Disconnect the vacuum hose from port F on the vacuum switching valve (for ACIS).

b. Connect the Techstream to the DLC3.

c. Start the engine.

d. Enter the following menus: Powertrain/Engine and ECT/Active Test/Active the VSV for Intake

Control.

e. Operate the VSV for ACIS.

f. Check the VSV air flow when switching the VSV.

2008 Toyota Tundra

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

OK

ACTIVE TEST REFERENCE

Fig. 313: Checking Vacuum Switching Valve

NG : Go to step 4

OK : Go to Next Step

2. CHECK VACUUM HOSES (VACUUM SWITCHING VALVE - INTAKE AIR CONTROL

VALVE, INTAKE MANIFOLD)

NG : REPAIR OR REPLACE VACUUM HOSES

OK : Go to Next Step

3. INSPECT INTAKE MANIFOLD (INTAKE AIR CONTROL VALVE)

a. Inspect the intake air control valve. (See INSPECTION ).

NG : REPLACE INTAKE MANIFOLD . (See INTAKE MANIFOLD ).

OK : PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE (See PROBLEM SYMPTOMS TABLE )

4. INSPECT VACUUM SWITCHING VALVE

a. Inspect the vacuum switching valve. (See INSPECTION ).

NG : REPLACE VACUUM SWITCHING VALVE . (See VACUUM SWITCHING VALVE (FOR
ACIS) ).

OK : Go to Next Step

Test Condition

Specified Condition

VSV is ON

Air from port E flows out through port F

VSV is OFF Air from port E flows out through air filter

2008 Toyota Tundra

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

5. CHECK HARNESS AND CONNECTOR (INTAKE AIR CONTROL VALVE - ECM,

INTEGRATION RELAY)

a. Remove the EFI NO. 2 fuse from the engine room relay block.

b. Check the EFI NO. 2 fuse.

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION

d. Reinstall the EFI NO. 2 fuse.

e. Disconnect the D61 intake air control valve connector.

f. Disconnect the D74 ECM connector.

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

h. Disconnect the 1B integration relay connector.

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connection Condition Specified Condition

EFI NO. 2 fuse

Always

Below 1 ohms

Tester Connection

Condition Specified Condition

D61-2 - D74-62 (ACIS)

Always

Below 1 ohms

D61-1 - 1B-4

Always

Below 1 ohms

D61-2 or D74-62 (ACIS) - Body ground Always

10 kohms or higher

D61-1 or 1B-4 - Body ground

Always

10 kohms or higher

2008 Toyota Tundra

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