Lexus RX300 (MCU15). Service manual - part 230

DI–152

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DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

(6)

Shift into the D range. Press all the way down on the accelerator pedal with your right foot. Quickly
read the stall speed at this time.

Stall speed: 2,325 - 2,775 rpm

Evaluation:

Problem

Possible cause

(a) Stall speed low in D and R ranges

S Engine output may be insufficient

S Stator one–way clutch is operating properly

HINT: If more than 600 rpm below the specified value, the torque

converter could be faulty.

(b) Stall speed high in D range

S Line pressure too low

S Forward clutch slipping

S No. 2 one–way clutch not operating properly

S O/D clutch slipping

S Line pressure too low

S Direct clutch slipping

S 1st and reverse brake slipping

S O/D clutch slipping

(d) Stall speed high in D and R ranges

S Line pressure too low

S Improper fluid level

S O/D one–way clutch not operating properly

(b)

Measure the time lag.
When the shift lever is shifted while the engine is idling, there will be a certain time lapse or lag before
the shock can be felt. This is used for checking the condition of the O/D direct clutch, forward clutch,
and 1st and reverse brake.

NOTICE:

Do the test at normal operating fluid temperature 50 – 80 °C (122 – 176 °F).

Be sure to allow 1 minute interval between tests.

Take 3 measurements and take the average value.
(1)

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

(2)

Fully apply the parking brake.

(3)

Start the engine and check idle speed.

Idle speed: 700 ± 50 rpm (In N range and air conditioner OFF)
(4)

Shift the shift lever from N to D range. Using a stop watch, measure the time from when the lever
is shifted until the shock is felt.
In the same manner, measure the time lag for N → R.

Time lag:
N → D Less than 1.2 seconds
N → R Less than 1.5 seconds

Evaluation (If N → D time or N → R time lag is longer than specified):

Problem

Possible cause

N → D time lag is longer

S Line pressure too low

S Forward clutch worn

S O/D one–way clutch not operating

N → R time lag is longer

S Line pressure too low

S Direct clutch worn

S 1st and reverse brake worn

S O/D one–way clutch not operating properly

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DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–153

LEXUS RX300 (RM785E)

HYDRAULIC TEST

Measure the line pressure.
NOTICE:

Do the test at normal operation fluid temperature 50 – 80 °C (122 – 176 °F)

The line pressure test should always be carried out in pairs. One technician should observe
the conditions of wheels or wheel stoppers outside the vehicle while the other is doing the test.

Be careful to prevent SST’s hose from interfering with the exhaust pipe.
(1)

Warm up the ATF.

(2)

Remove the test plug on the transaxle case front left side and connect SST.
(See page AX–30 for the location to connect SST)

SST

09992–00095 (09992–00231, 09992–00271)

(3)

Fully apply the parking brake and chock the 4 wheels.

(4)

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

(5)

Start the engine and check idling speed.

(6)

Keep your left foot pressed firmly on the brake pedal and shift into D range.

(7)

Measure the line pressure when the engine is idling.

(8)

Depress the accelerator pedal all the way down. Quickly read the highest line pressure when
engine speed reaches stall speed.

(9)

In the same manner, do the test in R range.

Specified line pressure:

Condition

D range kPa (kgf/cm

psi)

R range kPa (kgf/cm

psi)

Idling

372 – 412 (3.8 – 4.2, 54 – 59)

672 – 742 (6.9 – 7.6, 97 – 107)

Stall

931 – 1,031 (9.5 – 10.5, 134 – 149)

1,768 – 1,968 (18.0 – 20.1, 255 – 284)

If the measured pressure is not up to specified value, recheck the throttle cable adjustment and retest.
Evaluation

Problem

Possible cause

If the measured values at all range are higher

S Throttle cable out of adjustment

S Throttle valve defective

S Regulator valve defective

If the measured values at all range are lower

S Throttle cable out of adjustment

S Throttle valve defective

S Regulator valve defective

S Oil pump defective

S O/D direct clutch defective

If pressure is low in the D range only

S D range circuit fluid leakage

S Forward clutch defective

If pressure is low in the R range only

S R range circuit fluid leakage

S Direct clutch defective

S 1st and reverse brake defective

D02942

DI–154

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DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

MANUAL SHIFTING TEST

HINT:
With this test, it can be determined whether the trouble is within
the electrical circuit or is a mechanical problem in the transaxle.
(a)

Disconnect the solenoid wire.

(b)

Inspect the manual driving operation.
Check that the shift and gear positions correspond with
the table below.
While driving, shift through the L, 2 and D ranges. Check
that the gear change corresponds to the shift range.

Shift range

Gear position

O/D

1st

Reverse

Pawl Lock

HINT:
If the L, 2 and D range gear positions are difficult to ranges are
difficult to distinguish, do the following read test.
If any abnormality is found in the above test, the problem is in
the transaxle itself.
(c)

Connect the solenoid wire.

(d)

Cancel out DTC (See page DI–144).

DI0CH–10

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DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–155

LEXUS RX300 (RM785E)

DIAGNOSTIC TROUBLE CODE CHART

If a DTC is displayed during the DTC check, check the circuit listed for that code in the table below and pro-
ceed to the page given.
HINT:

: F...Check engine warning light (CHK ENG) light up

DTC No.

(See Page)

Detection Item

Trouble Area

*CHK ENG

Memory

P0500

(DI–163)

Vehicle Speed Sensor Malfunc-

tion

S Open or short in No. 1 vehicle speed sensor circuit

S No. 1 vehicle speed sensor

S Combination meter

S Engine & ECT ECU

S Automatic transaxle assembly

P0710

(DI–166)

Transmission Fluid Temperature

Sensor Malfunction

S Open or short in ATF temperature sensor circuit

S ATF temperature sensor

S Engine & ECT ECU

P0711

(DI–166)

Transmission Fluid Temperature

Sensor Circuit Range/Perfor-

mance Problem

S Open in ATF temperature sensor circuit

S ATF temperature sensor

S Engine & ECT ECU

P0750

(DI–168)

Shift Solenoid A Malfunction

(SL1 Solenoid Valve)

S SL1 solenoid valve is stuck open or closed

S Valve body is blocked up or stuck

P0753

(DI–170)

Shift Solenoid A Electrical Mal-

function

(SL1 Solenoid Valve)

S Open or short in SL1 solenoid valve circuit

S SL1 solenoid valve

S Engine & ECT ECU

P0755

(DI–168)

Shift Solenoid B Malfunction

(SL2 Solenoid Valve)

S SL2 solenoid valve is stuck open or closed

S Valve body is blocked up or stuck

P0758

(DI–170)

Shift Solenoid B Electrical Mal-

function

(SL2 Solenoid Valve)

S Open or short in SL2 solenoid valve circuit

S SL2 solenoid valve

S Engine & ECT ECU

P0765

(DI–168)

Shift Solenoid D Malfunction

(S4 Solenoid Valve)

S S4 solenoid valve is stuck open or closed

S Valve body is blocked up or stuck

P0768

(DI–170)

Shift Solenoid D Electrical Mal-

function

(S4 Solenoid Valve)

S Open or short in S4 solenoid valve circuit

S S4 solenoid valve

S Engine & ECT ECU

P0770

(DI–176)

Shift Solenoid E Malfunction

(DSL Solenoid Valve)

S DSL solenoid valve is stuck open or closed

S Valve body is blocked up or stuck

S Lock–up clutch

P0773

(DI–178)

Shift Solenoid E Electrical Mal-

function

(DSL Solenoid Valve)

S Open or short in DSL solenoid valve circuit

S DSL solenoid valve

S Engine & ECT ECU

P1520

(DI–180)

Stop light switch circuit

S Open or short in stop light switch circuit

S Stop light switch

S Engine & ECT ECU

P1725

(DI–181)

NT Revolution Sensor Circuit

Malfunction

(Input Turbine Speed Sensor)

S Open or short in input turbine speed sensor circuit

S Input turbine speed sensor

S Engine & ECT ECU

P1730

(DI–183)

NC Revolution Sensor Circuit

Malfunction

(Counter Gear Speed Sensor)

S Open or short in counter gear speed sensor circuit

S Counter gear speed sensor

S Engine & ECT ECU

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