Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Active Control Engine Mount System

DESCRIPTION

LOCATION

*1

No. 2 Vacuum Switching Valve Assembly (for Active Control Engine Mount)

*2

Front Engine Mounting Insulator Assembly

The active control engine mount system decreases engine vibration at a low engine speed using the No. 2 vacuum switching valve assembly (for active control engine mount). The No. 2 vacuum switching valve assembly (for active control engine mount) is controlled by a pulse signal transmitted to the No. 2 vacuum switching valve assembly (for active control engine mount) from the ECM. The frequency of this pulse signal is matched to the engine speed to decrease engine vibration.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK VACUUM HOSES

(a) Check the air and vacuum hoses for looseness, disconnection and blockage.

OK:

No looseness, disconnection or blockage.

*1

Engine

*2

Intake Air Surge Tank Assembly

*3

Front Engine Mounting Insulator

*4

ECM

*5

No. 2 Vacuum Switching Valve Assembly (for Active Control Engine Mount)

NG

REPAIR OR REPLACE VACUUM HOSES

OK

2.

CHECK VACUUM

(a) Disconnect the vacuum hose from the intake air surge tank assembly.

(b) Start the engine.

(c) Check that the disconnected port located on the intake air surge tank assembly applies suction to your finger.

OK:

Vacuum exists.

NG

CHECK AND REPLACE VACUUM SOURCE AND HOSES

OK

3.

INSPECT NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT) (OPERATION)

(a) Inspect the No. 2 vacuum switching valve assembly (for active control engine mount) operation.

Click here

NG

REPLACE NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT)

OK

4.

INSPECT NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT) (RESISTANCE)

(a) Inspect the No. 2 vacuum switching valve assembly (for active control engine mount) resistance.

Click here

NG

REPLACE NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT)

OK

5.

INSPECT FRONT ENGINE MOUNTING INSULATOR

(a) Inspect the front engine mounting insulator.

Click here

NG

REPLACE FRONT ENGINE MOUNTING INSULATOR

OK

6.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT))

*a

Front view of wire harness connector

(to No. 2 Vacuum Switching Valve Assembly (for Active Control Engine Mount))

(a) Disconnect the No. 2 vacuum switching valve assembly (for active control engine mount) connector.

(b) Turn the engine switch on (IG).

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

D10-1 - Body ground

Engine switch on (IG)

11 to 14 V

NG

GO TO STEP 8

OK

7.

CHECK HARNESS AND CONNECTOR (NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT) - ECM)

(a) Disconnect the No. 2 vacuum switching valve assembly (for active control engine mount) connector.

(b) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D10-2 - D2-39 (ACM)

Always

Below 1 Ω

D10-2 or D2-39 (ACM) - Body ground and other terminals

Always

10 kΩ or higher

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.

CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - NO. 2 VACUUM SWITCHING VALVE ASSEMBLY (FOR ACTIVE CONTROL ENGINE MOUNT))

(a) Disconnect the semiconductor pwr integration ECU connector.

(b) Disconnect the No. 2 vacuum switching valve assembly (for active control engine mount) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1G-1 - D10-1

Always

Below 1 Ω

1G-1 or D10-1 - Body ground and other terminals

Always

10 kΩ or higher

OK

GO TO ECM POWER SOURCE CIRCUIT

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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