Lexus RX300 (MCU15). Service manual — part 232

DI0CO–12

DI–160

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

PROBLEM SYMPTOMS TABLE

If a normal code is displayed during the diagnostic trouble code check but the trouble still occurs, check the
circuits for each symptom in the order given in the charts on the following pages and proceed to the page
given for troubleshooting.
The Matrix Chart is divided into 3 chapters.
Chapter 1: Electronic Circuit Matrix Chart
Chapter 2: On–vehicle Repair Matrix Chart
Chapter 3: Off–vehicle Repair Matrix Chart

S

If the instruction ”Proceed to next circuit inspection shown on matrix chart” is given in the flow chart
for each circuit, proceed to the circuit with the next highest number in the table to continue the check.

S

If the trouble still occurs even though there are no abnormalities in any of the other circuits, then check
and replace the Engine & ECT ECU.

1.

Chapter 1: Electronic Circuit Matrix Chart

Symptom

Suspect Area

See page

No up–shift (1st → 2nd)

Engine & ECT ECU

IN–32

No up–shift (2nd → 3rd)

Engine & ECT ECU

IN–32

No up–shift (3rd → O/D)

3. O/D main switch circuit

4. O/D cancel signal circuit

5. Engine & ECT ECU

DI–197

DI–194

IN–32

No down–shift (O/D → 3rd)

Engine & ECT ECU

IN–32

No down–shift (3rd → 2nd)

Engine & ECT ECU

IN–32

No down–shift (2nd → 1st)

Engine & ECT ECU

IN–32

No lock–up or No lock–up off

Engine & ECT ECU

IN–32

Shift point too high or too low

Engine & ECT ECU

IN–32

Up–shift to 2nd while in L range

Engine & ECT ECU

IN–32

Up–shift to 3rd while in L range

Engine & ECT ECU

IN–32

Up–shift to O/D from 3rd

1. O/D main switch circuit

2. Engine & ECT ECU

DI–197

IN–32

Up–shift to O/D from 3rd while engine is cold

Engine & ECT ECU

IN–32

Harsh engagement (N → D)

Engine & ECT ECU

IN–32

Harsh engagement (Lock–up)

Engine & ECT ECU

IN–32

Harsh engagement (Any driving range)

Engine & ECT ECU

IN–32

Poor acceleration

Engine & ECT ECU

IN–32

Large shift shock or engine stalls when starting off or stopping

Engine & ECT ECU

IN–32

No pattern select

1. Pattern select switch circuit

2. Engine & ECT ECU

DI–192

IN–32

*No kick–down

1. Kick–down switch circuit

2. Engine & ECT ECU

DI–200

IN–32

*: LHD only

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–161

LEXUS RX300 (RM785E)

2.

Chapter 2: On–Vehicle Repair
(L: U140F AUTOMATIC TRANSAXLE Repair Manual Pub. No. RM848E)

Symptom

Suspect Area

See page

Vehicle does not move in any forward range and reverse range

1. Service manual valve

2. Throttle valve

3. Primary regulator valve

4. Off–vehicle repair matrix chart

L

L

L

–

Vehicle does not move in R range

Off–vehicle repair matrix chart

–

No up–shift (1st → 2nd)

1. 1–2 shift valve

2. Off–vehicle repair matrix chart

L

–

No up–shift (2nd → 3rd)

1. 2–3 shift valve

2. Off–vehicle repair matrix chart

L

–

No up–shift (3rd → O/D)

1. 3–4 shift valve

2. Off–vehicle repair matrix chart

L

–

No down–shift (O/D → 3rd)

3–4 shift valve

L

No down–shift (3rd → 2nd)

2–3 shift valve

L

No down–shift (2nd → 1st)

1–2 shift valve

L

No lock–up or No lock–up off

1. Lock–up relay valve

2. Off–vehicle repair matrix chart

L

–

Harsh engagement (N → D)

1. C

1

accumulator

2. Off–vehicle repair matrix chart

L

–

Harsh engagement (N → R)

1. C

2

accumulator

2. No. 1 accumulator control valve

3. Off–vehicle repair matrix chart

L

L

Harsh engagement (N → L)

Low coast modulator valve

L

Harsh engagement (Lock–up)

1. Lock–up relay valve

2. Off–vehicle repair matrix chart

L

–

Harsh engagement (1st → 2nd → 3rd → O/D)

1. Throttle modulator valve

2. Cut back valve

3. Throttle valve

L

L

L

Harsh engagement (2nd → 3rd)

C

2

accumulator

L

Harsh engagement (3rd → O/D)

B

0

accumulator

L

Harsh engagement (O/D → 3rd)

1. C

0

accumulator

2. B

0

accumulator

L

L

Slip or shudder (Forward and reverse)

1. Throttle valve

2. Oil strainer

3. Off–vehicle repair matrix chart

L

L

–

No engine braking (1st: L range)

1. Low coast modulator valve

2. Off–vehicle repair matrix chart

L

–

No engine braking (2nd: 2 range)

1. 2nd coast modulator valve

2. Off–vehicle repair matrix chart

L

–

*No kick–down

1. 1–2 shift valve

2. 2–3 shift valve

3. 3–4 shift valve

4. Off–vehicle repair matrix chart

L

L

L

–

*: LHD only

DI–162

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

3.

Chapter 3: Off–Vehicle Repair
(L: U140F AUTOMATIC TRANSAXLE Repair Manual Pub. No. RM848E)

Symptom

Suspect Area

See page

Vehicle does not move in any forward range and reverse range

1. Front and rear planetary gear

2. U/D planetary gear

3. U/D one–way clutch (F

2

)

4. Forward clutch (C

1

)

5. U/D brake (B

3

)

L

L

L

L

L

Vehicle does not move in R range

1. Front and rear planetary gear unit

2. U/D planetary gear unit

3. Direct clutch (C

2

)

4. U/D brake (C

3

)

4. 1st and reverse brake (B

2

)

L

L

L

L

L

No up–shift (1st → 2nd)

1. No. 1 one–way clutch (F

1

)

2. 2nd brake (B

1

)

L

L

No up–shift (2nd → 3rd)

Direct clutch (C

2

)

L

No up–shift (3rd → O/D)

U/D clutch (C

3

)

L

No lock–up or No lock–up off

Torque converter

L

Harsh engagement (N → D)

1. Forward clutch (C

1

)

2. U/D one–way clutch (F

2

)

3. No. 1 one–way clutch (F

1

)

L

L

L

Harsh engagement (N → R)

1. Direct clutch (C

2

)

2. 1st and reverse brake (B

2

)

L

L

Harsh engagement (Lock–up)

Torque converter

L

Slip or shudder (Forward range: After warm–up)

1. Torque converter

2. Forward clutch (C

1

)

3. Direct clutch (C

2

)

4. U/D brake (C

3

)

5. No. 1 one–way clutch (F

1

)

6. U/D one–way clutch (F

2

)

L

L

L

L

L

L

Slip or shudder (R range)

1. Direct clutch (C

2

)

2. 1st and reverse brake (B

2

)

L

L

Slip or shudder (1st)

No. 1 one–way clutch (F

1

)

L

Slip or shudder (2nd)

1. U/D one–way clutch (F

2

)

2. 2nd brake (B

1

)

L

L

Slip or shudder (3rd)

Direct clutch (C

2

)

L

Slip or shudder (O/D)

U/D clutch (C

3

)

L

No engine braking (1st ∼ 3rd: D range)

U/D brake (B

3

)

L

No engine braking (1st: L range)

1st and reverse brake (B

2

)

L

No engine braking (2nd: 2 range)

2nd brake (B

1

)

L

Poor acceleration (All range)

1. Torque converter

2. U/D planetary gear

L

L

Poor acceleration (O/D)

1. U/D clutch (C

3

)

2. U/D planetary gear

L

L

Large shift shock or engine stalls when starting off or stopping

Torque converter

L

DI84K–01

Q00515

Speed Sensor

Combination
Meter

Engine & ECT ECU

Transaxle

4–Pulse

4–Pulse

Q00515 Q00514

D10064

V–W

V–W

Engine & ECT ECU

SPD

5 V

Combination Meter

IJ1

8

C14

10

22

E10

V–W

3E

2

3K

12

J/B No. 3

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–163

LEXUS RX300 (RM785E)

CIRCUIT INSPECTION

DTC

P0500

Vehicle Speed Sensor Malfunction

CIRCUIT DESCRIPTION

The vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which is rotated
by the transaxle output shaft via the driven gear. After this signal is converted into a more precise rectangular
waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the Engine
& ECT ECU. The Engine & ECT ECU determines the vehicle speed based on the frequency of these pulse
signals.

DTC No.

DTC Detecting Condition

Trouble Area

P0500

No vehicle speed sensor signal to Engine & ECT ECU under

conditions (a) and (b): (2 trip detection logic)

(a) Neutral start switch is OFF

(b) Vehicle is being driven

S Open or short in speed sensor circuit

S No. 1 vehicle speed sensor

S Combination meter

S Engine & ECT ECU

Clutch or brake slips or gear is broken.

Engine & ECT ECU

S Automatic transaxle assembly

WIRING DIAGRAM