Lexus RX300 (MCU15). Service manual — part 229

N09348

Vehicle
Harness

Interface
Box

Break–Out–Box

DI–148

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

NOTICE:
If the hand–held tester switches the engine ECU from nor-
mal mode to check mode or vice–versa, or if the ignition
switch is turned from ON to ACC or OFF during check
mode, the DTCs and freezed frame data will be erased.

(c)

Engine ECU Terminal Values Measurement Using
Break–Out–Box and Hand–Held Tester
(1)

Hook up the break–out–box and hand–held tester
to the vehicle.

(2)

Read the engine ECU input/output values by follow-
ing the prompts on the tester screen.

HINT:

S

Hand–held tester has a ”Snapshot” function.
This records the measured values and is effective in the
diagnosis of intermittent problems.

S

Please refer to the hand–held tester/break–out–box op-
erator’s manual for further details.

4.

ROAD TEST

NOTICE:
Perform the test at normal operating ATF temperature 50 – 80

°C (122 – 176 °F).

(a)

D range test
Shift into the D range and fully depress the accelerator pedal and and check the following points:
(1)

Check up–shift operation.
1 → 2, 2 → 3 and 3 → O/D up–shift takes place, at the shift point shown in the automatic shift
schedule (See page SS–22).

HINT:

S

O/D Gear Up–shift Prohibition Control (1. Coolant temp. is 60

°C (140 °F) or less. 2. If there is a 10

km/h (6 mph) difference between the set cruise control speed and vehicle speed.)

S

O/D Gear Lock–up Prohibition Control (1. Brake pedal is depressed. 2. Coolant temp. is 60

°C

(140 °F) or less.)
(2)

Check for shift shock and slip.
Check for shock and slip at the 1 → 2, 2 → 3 and 3 → O/D up–shifts.

(3)

Check for abnormal noises and vibration.
Run at the D range lock–up or O/D gear and check for abnormal noises and vibration.

HINT:
The check for the cause of abnormal noises and vibration must be done very thoroughly as it could also be
due to loss of balance in the differential torque converter, etc..

(4)

Check kick–down operation.
While running in the D range, 2nd, 3rd and O/D gears, check to see that the possible kick–down
vehicle speed limits for 2 → 1, 3 → 2 and O/D → 3 kick–downs conform to those indicated on
the automatic shift schedule (See page SS–22).

(5)

Check abnormal shock and slip at kick–down.

(6)

Check the lock–up mechanism.

S

Drive in D range, O/D gear, at a steady speed (lock–up ON) of about 80 km/h (49 mph).

AT3417

OK if hot

Add if hot

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–149

LEXUS RX300 (RM785E)

S

Lightly depress the accelerator pedal and check that the engine speed does not change
abruptly.

If there is a big jump in engine speed, there is no lock–up.
(b)

2 range test
Shift into the 2 range and fully depress the accelerator pedal and check the following points:
(1)

Check up–shift operation.
Check to see that the 1 → 2 up–shift takes place and that the shift point conforms to the automatic
shift schedule (See page SS–22).

HINT:
There is no O/D up–shift and lock–up in the 2 range.

(2)

Check engine braking.
While running in the 2 range and 2nd gear, release the accelerator pedal and check the engine
braking effect.

(3)

Check for abnormal noises during acceleration and deceleration, and for shock at up–shift and
down–shift.

(c)

L range test
Shift into the 2 range and fully depress the accelerator pedal and check the following points:
(1)

Check no up–shift.
While running in the L range, check that there is no up–shift to 2nd gear.

(2)

Check engine braking.
While running in the L range, release the accelerator pedal and check the engine braking effect.

(3)

Check for abnormal noises during acceleration and deceleration.

(d)

R range test
Shift into the R range and fully depress the accelerator pedal and check for slipping.

CAUTION:
Before conducting this test ensure that the test area is free from people and obstruction.
(e)

P range test
Stop the vehicle on a grade (more than 5

°) and after shifting into the P range, release the parking

brake. Then, check to see that the parking lock pawl holds the vehicle in place.

5.

BASIC INSPECTION

(a)

Check the fluid level.

HINT:

S

Drive the vehicle so that the engine and transaxle are at
normal operating temperature.
Fluid temp.: 70 – 80

°C (158 – 176 °F)

S

Only use the COOL range on the dipstick as a rough refer-
ence when the fluid is replaced or the engine does not
run.

(1)

Park the vehicle on a level surface and set the park-
ing brake.

(2)

With the engine idling and the brake pedal de-
pressed, shift the shift lever into all ranges from P
to L range and return to P range.

(3)

Pull out the dipstick and wipe it clean.

(4)

Push it back fully into the pipe.

(5)

Pull it out and check that the fluid level is in the HOT
range.

D02941

AT8562

AT3417

OK if hot

Add if hot

DI–150

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

If the level is at the low side, add new fluid.

Fluid type: ATF Type T–IV or equivalent
Capacity: 3.9 liters (4.1 US qts, 3.4 lmp. qts)

NOTICE:
Do not overfill.
(b)

Check the fluid condition.

If the level is at the low side, add new fluid.

(c)

Replace the ATF.
(1)

Remove the drain plug and drain the fluid.

(2)

Reinstall the drain plug securely.

(3)

With the engine OFF add new fluid through the oil
filler pipe.

Fluid type: ATF Type T–IV or equivalent
Capacity: 3.9 liters (4.1 US qts, 3.4 lmp. qts)
(4)

Start the engine and shift the shift lever into all
ranges from P to L range and then shift into P range.

(5)

With the engine idling, check the fluid level. Add
fluid up to the COOL level on the dipstick.

(6)

Check the fluid level at the normal operating tem-
perature, 70 – 80

°C (158 – 176 °F), and add as

necessary.

NOTICE:
Do not overfill.
(d)

Check the fluid leaks.
Check for leaks in the transaxle.

If there are leaks, it is necessary to repair or replace O–rings,
gasket, oil seals, plugs or other parts.

D02943

Q04604

Q04700

Bolt

Neutral Basic Line

Groove

Bolt

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DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–151

LEXUS RX300 (RM785E)

(e)

Inspect and adjust the shift lever position.
When shifting the shift lever from the N range to other
ranges, check that the lever can be shifted smoothly and
accurately to each range and that the position indicator is
not aligned with the correct position.

If the indicator is not aligned with the correct position, carry out
the following adjustment procedures.

(1)

Loosen the nut on the shift lever.

(2)

Push the control shaft fully rearward.

(3)

Return the control shaft lever 2 notches to N range.

(4)

Set the shift lever to N range.

(5)

While holding the shift lever lightly toward the R
range side, tighten the shift lever nut.

Torque: 13 N·m (130 kgf·cm, 9 ft·lbf)
(6)

Start the engine and make sure that the vehicle
moves forward when shifting the lever from the N to
D range and reverses when shifting it to the R
range.

(f)

Inspect and adjust the neutral start switch.
Check that the engine can be started with the shift lever
only in the N or P range, but not in other ranges.

If it is not as stated above, carry out the following adjustment
procedures.

(1)

Loosen the neutral start switch bolt and set the shift
lever to the N range.

(2)

Align the groove and neutral basic line.

(3)

Hold in position and tighten the bolt.

Torque: 5.4 N·m (55 kgf·cm, 48 in·lbf)

For continuity inspection of the neutral start switch,
see page DI–188.

(g)

Check the idle speed.
Idle speed: 700 ± 50 rpm
(In N range and air conditioner OFF)

6.

MECHANICAL SYSTEM TESTS

(a)

Measure the stall speed.
The object of this test is to check the overall performance of the transaxle and engine by measuring
the stall speeds in the D and R ranges.

NOTICE:

S

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

S

Do not continuously run this test longer than 5 seconds.

S

To ensure safety, conduct this test in a wide, clear level area which provides good traction.

S

The stall test should always be carried out in pairs. One technician should observe the condi-
tions of wheels or wheel stoppers outside the vehicle while the other is doing the test.
(1)

Chock the 4 wheels.

(2)

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

(3)

Fully apply the parking brake.

(4)

Keep your left foot pressed firmly on the brake pedal.

(5)

Start the engine.