Toyota Venza: Air Conditioning Compressor Magnetic Clutch Circuit

Toyota Venza Service Manual / Heating / Air Conditioning / Air Conditioning System / Air Conditioning Compressor Magnetic Clutch Circuit

DESCRIPTION

When the A/C amplifier is turned on, a magnetic clutch ON signal is sent from the MGC terminal of the A/C amplifier. Then, the MGC relay turns on to operate the magnetic clutch.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	CHECK CAN COMMUNICATION SYSTEM

(a) Use the Techstream to check if the CAN communication system is functioning normally.

Result	Proceed to
CAN DTC is not output	A
CAN DTC is output	B

GO TO CAN COMMUNICATION SYSTEM

2.	INSPECT RELAY (MGC)

(a) Remove the MGC relay from the engine room relay block and junction block.

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

Standard Resistance:

Tester Connection	Specified Condition
3 - 5	10 kΩ or higher
3 - 5	Below 1 Ω (when battery voltage is applied to terminals 1 and 2)

Tester Connection

Specified Condition

3 - 5

10 kΩ or higher

3 - 5

Below 1 Ω

(when battery voltage is applied to terminals 1 and 2)

REPLACE RELAY (MGC)

3.	CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK - BATTERY)

(a) Remove the MGC relay from the engine room relay block and junction block.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
Relay block MGC relay terminal 1 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*1	Component without relay installed (Engine Room Relay Block and Junction Block)

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)

(a) Disconnect the A/C amplifier connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
D47-20 (MGC) - Body ground	Ignition switch off	Below 1 V
D47-20 (MGC) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*1	Front view of wire harness connector (to A/C Amplifier)

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	INSPECT A/C AMPLIFIER

(a) Reconnect the A/C amplifier connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
D47-20 (MGC) - Body ground	Ignition switch ON A/C switch: off	11 to 14 V
D47-20 (MGC) - Body ground	Ignition switch ON A/C switch: on	Below 1 V

Tester Connection

Condition

Specified Condition

D47-20 (MGC) - Body ground

Ignition switch ON

A/C switch: off

11 to 14 V

D47-20 (MGC) - Body ground

Ignition switch ON

A/C switch: on

Below 1 V

Text in Illustration

*1	Component with harness connected (A/C Amplifier)

REPLACE A/C AMPLIFIER

6.	INSPECT A/C COMPRESSOR

(a) Disconnect the A/C compressor connector.

(b) Disconnect the magnetic clutch connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
B9-3 (MG+) - d3-1	Always	Below 1 Ω
B9-3 (MG+) - Body ground	Always	10 kΩ or higher

Text in Illustration

Component without harness connected

(A/C Compressor)

Component without harness connected

(Magnetic Clutch)

REPLACE A/C COMPRESSOR

7.	INSPECT MAGNETIC CLUTCH

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
d3-1 - Body ground	20°C (68°F)	3.8 to 4.2 Ω

(b) When connector terminal d3-1 is connected to a positive (+) battery terminal, check that the following occurs: 1) the magnetic clutch operating sound can be heard, and 2) the magnetic clutch hub and rotor lock.

Text in Illustration

*1	Component without harness connected (Magnetic Clutch)

REPLACE MAGNETIC CLUTCH

8.	CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK - BATTERY)

(a) Remove the MGC relay from the engine room relay block and junction block.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
Relay block MGC relay terminal 5 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*1	Component without relay installed (Engine Room Relay Block and Junction Block)

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK - A/C COMPRESSOR)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Relay block MGC relay terminal 3 - B9-3 (MG+)	Always	Below 1 Ω
B9-3 (MG+) - Body ground	Always	10 kΩ or higher

Result:

Result	Proceed to
NG	A
OK (When troubleshooting according to Problem Symptoms Table)	B
OK (When troubleshooting according to the DTC)	C

Text in Illustration

Component without relay installed

(Engine Room Relay Block and Junction Block)

Front view of wire harness connector

(to A/C Compressor)

REPAIR OR REPLACE HARNESS OR CONNECTOR

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE A/C AMPLIFIER

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