Lexus RX300 (MCU15). Service manual - part 227

A14525

TC

E10

TC

CG

D3 
DLC3

4

P–B

5

5B

Engine ECU

IF

W–B

W–B

1

P–B

13

5B

5B

5C

11

4

3

J/B No. 5

F08565

CG

(–)

(+)

ON

TC

DI–140

–

DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

TC Terminal Circuit

CIRCUIT DESCRIPTION

Terminal TC and CG are located in the DLC3. When connecting these terminals, DTCs in normal mode or
test mode can be read through the check engine warning light in combination meter by flashing it.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

S

Even though terminal TC is not connected with terminal CG, the check engine warning light blinks.

S

For the above phenomenon, an open or short in the wire harness, or malfunction inside the engine
ECU is the likely cause.

1

Check voltage between terminals TC and CG of DLC3.

PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals TC and CG of the
DLC3.
OK:

Voltage: 9 – 14 V

OK

Check and replace engine ECU 
(See page IN–32).

NG

DI6SV–09

–

DIAGNOSTICS

ENGINE

DI–141

LEXUS RX300   (RM785E)

2

Check continuity between terminal CG of DLC3 and body ground.

NG

Repair or replace harness or connector.

OK

3

Check for open and short circuit in harness and connector between engine ECU
and DLC3 (See page IN–32).

NG

Repair or replace harness or connector.

OK

Check and replace engine ECU 
(See page IN–32).

DI0SL–19

Vehicle Brought to Workshop

Customer Problem Analysis

Check DTC and Freeze Frame Data (Precheck)

Record or Print DTC and Freeze Frame Data P. DI–144

Clear DTC and Freeze Frame Data P. DI–144

Visual Inspection

Setting the Check Mode Diagnosis P. DI–144

1

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–143

Connect an OBD scan tool or hand–held tester to DLC3.

If the display shows ”UNABLE TO CONNECT TO VEHICLE” when you have connected the
OBD scan tool/hand–held tester, inspect DLC3 P. DI–144

2

3

4

5

6

Symptom does not occur

Problem Symptom Confirmation

8

7

Symptom Simulation

P. IN–22

Symptom occurs

DTC Check

P. DI–144

OK Code

11

Basic Inspection

P. DI–144

DTC Chart

P. DI–155

Mechanical System Test

P. DI–144

Manual Shifting Test

P. DI–144

OK

OK

Chapter 1
(Electronic)

Chapter 2
(On–Vehicle)

P. DI–160

OK

Chapter 3
(Off–Vehicle)

OK

Problem Symptoms Table – P. DI–160

Circuit
Inspection

S Neutral Start Switch Circuit Check
S Kick–down Switch Circuit

NG

Parts Inspection

NG

NG

NG

Identification of Problem

Repair

Confirmation Test

End

NG

NG

12

NG

13

14

15

16

17

9

10

P. DI–160

P. DI–160

18

 

P. DI–163 to DI–200

DI–142

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300   (RM785E)

AUTOMATIC TRANSAXLE

HOW TO PROCEED WITH TROUBLESHOOTING

DI0SM–18

/                  /

How Often Does
Problem Occur?

/                  /

Automatic Transaxle
System Check Sheet

Inspector’s
Name              :

Customer’s Name

Date Vehicle
Brought In

/                   /

Registration No.

Registration Year

Frame No.

Odometer Reading

km
mile

Date Problem
Occurred

Continuous

Intermittent (           times a day)

Symptoms

No up–shift     (      1st → 2nd         2nd → 3rd         3rd → 4th         4th → O/D)

Vehicle does not vome (      Any range           Particular range)

No down–shift     (      O/D → 4th         4th → 3rd         3rd → 2nd         2nd → 1st)

Lock–up malfunction

Shift point too high or too low

Harsh engagement (      N → D        Lock–up        Any drive range)

Slip or shudder

No kick–down

Others

DTC Check

1st Time

2nd Time

Check Item

Normal code

Malfunction code (DTC                                  )

Normal code

Malfunction code (DTC                                  )

Check Engine
Warning Light
(CHK ENG)

Normal

Remains ON

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–143

LEXUS RX300   (RM785E)

CUSTOMER PROBLEM ANALYSIS CHECK