Compressor Lock Sensor Circuit - Air Conditioning System

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1422/22: Compressor Lock Sensor Circuit
B1422/22 - Compressor Lock Sensor Circuit

DESCRIPTION

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

The air conditioning amplifier reads the difference between compressor speed and engine speed. When the difference becomes too large, the air conditioning amplifier determines that the compressor locks, and turns the magnetic clutch off.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM

(a) Connect the Techstream to DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Select "Communication Bus Check"

OK:

All ECUs and sensors connected to the CAN communication system are displayed.

Result





B -- GO TO CAN COMMUNICATION SYSTEM How to Proceed With Troubleshooting
A -- Continue to next step.

2. CHECK AIR CONDITIONING AMPLIFIER





(a) Remove the air conditioning amplifier with the connectors still connected Removal.





(b) Using an oscilloscope, check the waveform.

Compressor Lock Signal





Result





(c) Remove the air conditioning amplifier.

C -- REPLACE AIR CONDITIONING AMPLIFIER Removal

B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Problem Symptoms Table
A -- Continue to next step.

3. INSPECT AIR CONDITIONING COMPRESSOR (LOCK SENSOR)





(a) Disconnect the D39 air conditioning compressor connector.

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

Standard Resistance:





(c) Reconnect the air conditioning compressor connector.

NG -- REPLACE AIR CONDITIONING COMPRESSOR (LOCK SENSOR) Removal
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - AIR CONDITIONING COMPRESSOR)

(a) Disconnect the H24 air conditioning amplifier connector.





(b) Disconnect the D39 air conditioning compressor connector.

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

Standard Resistance:





(d) Reconnect the air conditioning amplifier connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER Removal