Toyota 4Runner: Compressor Lock Sensor Circuit (B1422)

Toyota 4Runner Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / Compressor Lock Sensor Circuit (B1422)

SYSTEM DESCRIPTION

The ECM sends the engine speed signal to the air conditioning amplifier assembly via CAN communication.

The air conditioning amplifier assembly reads the difference between compressor speed and engine speed. When the difference becomes too large, the air conditioning amplifier assembly determines that the cooler compressor assembly is locked and turns the magnet clutch assembly off.

DTC Code	DTC Detection Condition	Trouble Area
B1422	Open or short in the compressor lock sensor circuit.	Cooler compressor assembly (A/C lock sensor) Compressor drive belt Harness or connector Air conditioning amplifier assembly CAN communication system

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

As DTC B1422 is also output when the compressor drive belt is damaged or loose, inspect the belt before performing troubleshooting.

PROCEDURE

1.	CHECK FOR DTC (CAN COMMUNICATION SYSTEM)

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

Result

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

GO TO CAN COMMUNICATION SYSTEM

2.	INSPECT COOLER COMPRESSOR ASSEMBLY (A/C LOCK SENSOR)

(a) Remove the cooler compressor assembly (A/C lock sensor) (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
1 - 2	20°C (68°F)	160 to 320 Ω

REPLACE COOLER COMPRESSOR ASSEMBLY (A/C LOCK SENSOR)

3.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - A/C LOCK SENSOR)

(a) Disconnect the F42 amplifier connector.

(b) Disconnect the B41 sensor connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F42-8 (LOCK) - B41-1	Always	Below 1 Ω
F42-13 (SG-2) - B41-2	Always	Below 1 Ω
F42-8 (LOCK) - Body ground	Always	10 kΩ or higher
F42-13 (SG-2) - Body ground	Always	10 kΩ or higher

Result

Result	Proceed to
OK (When troubleshooting according to problem symptoms table)	A
OK (When troubleshooting according to the DTC)	B
NG	C

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

Diagnostic Trouble Code Chart

DIAGNOSTIC TROUBLE CODE CHART HINT: If a trouble code is output during the DTC check, inspect the trouble areas listed for that code. For details of the code, refer to the "See page ...

Lost Communication with ECM (U0100,U0142,U0155)

DESCRIPTION The air conditioning amplifier communicates with the ECM, main body ECU (multiplex network body ECU) and combination meter through the CAN communication system. DTC Code ...

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