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Lexus RX300 (MCU15). Service manual - part 393

I12172

Navigation ECU

Multi Display Radio Receiver

Assembly

SST

TX–

TX+

TX–

TX+

Radio receiver assembly connector ”R4”

DI–802

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300 (RM785E)

Skip radio receiver assembly and check AVC–LAN.

PREPARATION:
(a)

Connect Multi Display connector.

(b)

Disconnect radio receiver assembly ”R” connector.

(c)

Using SST (Navigation Check Wire P/N 09843–18050),
connect the terminal TX+ to terminal TX– of ”R4” connec-
tor of radio receiver assembly.

CHECK:
Operate the panel switch and the touch switch of the display
and check that the navigation functions.
(Check that AVC–LAN is recovered.)

Replace the radio receiver assembly.

Replace the Navigation ECU.

DI3FP–02

Customer Problem Analysis

Check and Clear DTC (Precheck)

Vehicle Brought to Workshop

Problem Symptom Confirmation

Symptom Simulation

Symptom does not
occur

DTC Check

Normal code

DTC Chart

Problem Symptoms Table

Circuit Inspection

Actuator Check

Parts Inspection

Identification of Problem

Repair

Confirmation Test

End

Items inside

are titles of pages in this

manual with the page number indicated in the
bottom portion. See the indicated pages
for detailed explanations.

P DI–805

P. IN–22

P.DI–809

P. DI–812

P. DI–814 – DI–855

P.DI–805

Malfunction code

P. DI–804

Step 2, 5 and 11 : Diagnostic steps permitting the

use of the hand–held tester.

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–803

LEXUS RX300 (RM785E)

AIR CONDITIONING SYSTEM

HOW TO PROCEED WITH TROUBLESHOOTING

Perform troubleshooting in accordance with the procedure on the following page.

DI3FQ–01

Inspector’s name:

Customer’s Name

Registration No.

Registration Year

Frame No.

Odometer Reading

km
Miles

Date vehicle
Brought In

/ /

Date of Problem Occurrence

How Often does Problem Occur?

Weather

Outdoor Temperature

/ /

Continuous j Intermittent ( times a day)

Fine j Cloudy j Snowy j Various / Other

Hot j Warm j Cool j Cold (Approx.

°F
°C

)

Symptoms

Blower motor does not operation

Blower motor speed does not change

(Always Hi, Always Med, Always Lo)

Air Flow Control is
Faulty

Cabin temperature does not go down

Response is slow

Cannot change between FRS and REC

(Always Fresh or always Recirculating)

Will not enter the desired mode

Temperature
Control is Faulty

Air Inlet Control is
Faulty

Vent Control is
Faulty

DTC Check

1st Time

2nd Time

Normal Code j Malfunction Code (Code )

AIR CONDITIONING SYSTEM Check Sheet

Cabin temperature does not rise

Mode will not chage

DI–804

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

LEXUS RX300 (RM785E)

CUSTOMER PROBLEM ANALYSIS CHECK

DI3G9–02

AT0716

0.5 Seconds

OFF

Turn ignition switch ON with AUTO and
R/F switches held down.

Indicator Check

DTC Check
(Sensor Check)
(continuous operation)

DTC Check
(Sensor Check)
(stepped operation)

Cancel check mode and can start
A/C control

Actuator Check
(continuous operation)

Actuator Check
(stepped operation)

If both Auto switch and R/F switch
are not pressed at the same time.

OFF

R/F

AUTO

: Indicates a switch operation.

DEF

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–805

LEXUS RX300 (RM785E)

PRE–CHECK

WARNING FOR A/C COMPRESSOR LOCK

If compressor lock occurs during A/C operation, the A/C switch
indicator on the A/C control assembly starts blinking.
When this occurs, check for compressor lock (DTC B1422/22)
using diagnosis trouble code check then proceed to inspect the
circuit or the component.
Compressor lock sensor circuit. → (See page DI–826)

LIST OF OPERATION METHODS

By operating each of the A/C control switches as shown in the diagram below, it is possible to enter the diag-
nosis check mode.

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