Lexus IS250 · Service Manual HEATER & AIR CONDITIONING SYSTEM

B1422/22

Diagnostic trouble codes

DESCRIPTION

This sensor sends 1 pulse per engine revolution to the ECM.
If the ratio between engine and compressor speed deviates 20% or more compared to normal operation, the ECM turns the cooler compressor off and the indicator blinks at approximately 1 second intervals.
The ECM informs the A/C amplifier of the operation condition of the cooler compressor through multiplex communication (CAN and BEAN).
DTC No.
 DTC Detection Condition
 Trouble Area
B1422/22
 Open or short in compressor lock sensor circuit
  1. A/C compressor
  2. A/C compressor drive belt
  3. A/C compressor and magnetic clutch lock sensor
  4. Harness and connector between ECM and A/C compressor
  5. ECM
  6. A/C amplifier

WIRING DIAGRAM

E110808E01

INSPECTION PROCEDURE


1. CHECK MULTIPLEX COMMUNICATION SYSTEM

  1. Use the intelligent tester to check if the Multiplex Communication System (MPX) is functioning normally.

Result:
Result
 Proceed to
MPX DTC is not output
 A
MPX DTC is output
 B



B
GO TO MULTIPLEX COMMUNICATION SYSTEM
A


2. CHECK CAN COMMUNICATION SYSTEM

  1. Use the intelligent tester 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



B
GO TO CAN COMMUNICATION SYSTEM
A


3. INSPECT ECM

  1. E118400E02
    Remove the ECM with its connectors still connected.

  1. Measure the waveform of the connector.

    Standard:
    Tester Connection
    		 Condition
    		 Specified Condition
    E3-10 (LCKI) - Body ground
    		 Engine switch on (IG)
    AUTO switch ON
    A/C switch ON
    Magnetic clutch ON
    		 Pulse generation

Item
 Contents
Tool setting
 200 mV/DIV., 10 ms/DIV.
Vehicle condition
 Engine switch on (IG)
AUTO switch ON
A/C switch ON
Magnetic clutch ON

Result:
Result
 Proceed to
NG
 A
OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE)
 B
OK (When troubleshooting according to the DTC)
 C



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE ECM
A


4. INSPECT A/C COMPRESSOR (LOCK SENSOR)

  1. E118401E04
    Disconnect the A/C compressor connector.

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

    Standard resistance:
    Tester Connection
    		 Specified Condition
    E8-2 (SSR+) - E8-5 (SSR-)
    		 160 to 320 Ω



NG
REPLACE A/C COMPRESSOR (LOCK SENSOR)
OK


5. CHECK WIRE HARNESS (ECM - A/C COMPRESSOR)

  1. E118402E02
    Disconnect the A/C compressor connector.

  1. Disconnect the ECM connector.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    E3-10 (LCKI) - E8-2 (SSR+)
    		 Always
    		 Below 1 Ω
    E3-10 (LCKI) - Body ground
    		 Always
    		 10 kΩ or higher
    E8-5 (SSR-) - Body ground
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM


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