B1422

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

DTC B1422/22 - Compressor Lock Sensor Circuit

DESCRIPTION

The ECM sends the engine speed signal to the TACO terminal of the A/C amplifier. The A/C amplifier reads the difference between compressor speed and engine speed. When the difference becomes too big, the A/C amplifier determines that the compressor locks, and turns the magnetic clutch off.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT AIR CONDITIONING AMPLIFIER




(a) Remove the A/C amplifier with connectors still connected.
(b) Start the engine and press the A/C switch.




(c) Measure the waveform according to the condition in the table below.
Standard:





OK:
Wave form appears as shown in the illustration.
OK -- INSPECT AIR CONDITIONING AMPLIFIER (LOCK - SG-3)

NG -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONING AMPLIFIER)




(a) Disconnect the connector from A/C amplifier.




(b) Disconnect the connector from the ECM.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- GO TO SFI SYSTEM
3. INSPECT AIR CONDITIONING AMPLIFIER (LOCK - SG-3)




(a) Remove the A/C amplifier with connectors still connected.
(b) Start the engine and press the AUTO switch.




(c) Measure the waveform according to the condition in the table below.
Standard:





Result:





C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

4. INSPECT A/C LOCK SENSOR (W/ MAGNET CLUTCH COMPRESSOR ASSEMBLY)




(a) Disconnect the A/C lock sensor (with magnet clutch compressor assembly) connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPLACE A/C LOCK SENSOR (W/ MAGNET CLUTCH COMPRESSOR ASSEMBLY)
OK -- Continue to next step.

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




(a) Disconnect the connector from A/C lock sensor (w/ magnet clutch compressor assembly).




(b) Disconnect the connector from the A/C amplifier.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER