Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: How To Proceed With Troubleshooting

CAUTION / NOTICE / HINT

PROCEDURE

1.	VEHICLE BROUGHT TO WORKSHOP

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2.	INSPECT BATTERY VOLTAGE

(a) Inspect the battery voltage.

Standard Voltage:

11 to 14 V

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

(b) Check the fuses and relays.

(c) Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

(d) Using the Techstream, check the Data List item "Operation Limitation Control History Count".

Click here

Body Electrical > Air Conditioner > Data List

Tester Display
Operation Limitation Control History Count (Level1)
Operation Limitation Control History Count (Level2)

HINT:

If a value other than zero is displayed for "Operation Limitation Control History Count (Level1)" or "Operation Limitation Control History Count (Level2)", PTC heater operation may have been limited in the past. If the operation is still limited, the message "Operation of Electrical Items Restricted." will be displayed on the multi-information display in the combination meter assembly. In this case, inspect the charging system.

Click here

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3.	CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*

(a) Using the Techstream, check for CAN communication system DTCs.

Click here

Result	Proceed to
CAN communication system DTCs are not output	A
CAN communication system DTCs are output	B

B

GO TO CAN COMMUNICATION SYSTEM

A

4.	CHECK FOR DTC*

(a) Check for DTCs and note any codes that are output.

Click here

Body Electrical > Air Conditioner > Trouble Codes

(b) Clear the DTCs.

Click here

Body Electrical > Air Conditioner > Clear DTCs

(c) Recheck for DTCs. Based on the DTCs output above, try to force output of the air conditioning system DTC by simulating the operation indicated by the DTC.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTCs are output	B

B

GO TO DIAGNOSTIC TROUBLE CODE CHART

A

5.	PROBLEM SYMPTOMS TABLE

(a) Refer to Problem Symptoms Table.

Click here

Result	Proceed to
Fault is not listed in Problem Symptoms Table	A
Fault is listed in Problem Symptoms Table	B

B

GO TO PROBLEM SYMPTOMS TABLE

A

6.	OVERALL ANALYSIS AND TROUBLESHOOTING*

(a) Panel diagnosis (indicator check, sensor check).

Click here

(b) Data List / Active Test.

Click here

(c) Terminals of ECU.

Click here

(d) On-vehicle Inspection.

(e) Inspection.

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7.	ADJUST, REPAIR OR REPLACE

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END