Lexus IS250 · Service Manual HEATER & AIR CONDITIONING SYSTEM

HOW TO PROCEED WITH TROUBLESHOOTING

Troubleshooting

HINT:

Use the following procedures to troubleshoot the air conditioning system.
*: Use the intelligent tester.

1.VEHICLE BROUGHT TO WORKSHOP

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2.INSPECT BATTERY VOLTAGE

Inspect the battery voltage.

Standard voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the battery before proceeding.

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3.CHECK COMMUNICATION FUNCTION OF MULTIPLEX COMMUNICATION SYSTEM (BEAN)*

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.

A

4.CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*

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.

A

5.CHECK FOR DTC*

Check for DTCs and note any codes that are output.
Delete the DTCs.
Recheck for DTCs. Based on the DTCs output above, try to force output of the A/C system DTC by simulating the operation indicated by the DTC.

Result:

Result
Proceed to

DTC is not output
A

DTC is output
B

B.

A

6.PROBLEM SYMPTOMS TABLE

Refer to the problem symptoms table (Click here).

Result:

Result
Proceed to

Fault is not listed in problem symptoms table
A

Fault is listed in problem symptoms table
B

B.

A

7.OVERALL ANALYSIS AND TROUBLESHOOTING*

Actuator Check (Click here)
DATA LIST / ACTIVE TEST (Click here)
Terminals of ECU (Click here)
On-vehicle Inspection
Inspection

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8.ADJUST, REPAIR OR REPLACE

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