Lexus RX300 (MCU15). Service manual — part 236

D03447

D03448

D03725

(–)

(+)

(–)

(+)

DI–176

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

DTC

P0770

Shift Solenoid E Malfunction
(DSL Solenoid Valve)

SYSTEM DESCRIPTION

The Engine & ECT ECU uses the signals from the throttle position sensor, Air–flow meter and crankshaft
position sensor to monitor the engagement condition of the lock–up clutch.
Then the Engine & ECT ECU compares the engagement condition of the lock–up clutch with the lock–up
schedule in the Engine & ECT ECU memory to detect mechanical trouble of the DSL solenoid valve, valve
body and torque converter.

DTC No.

DTC Detecting Condition

Trouble Area

P0770

Lock–up does not occur when driving in the lock–up range

(normal driving at 80 km/h [50 mph]), or lock–up remains ON

in the lock–up OFF range.

(2 trip detection logic)

S DSL solenoid valve is stuck open or closed

S Valve body blocked up or stuck

S Lock–up clutch

INSPECTION PROCEDURE

1

Check DSL solenoid valve operation.

PREPARATION:
(a)

Remove the oil pan.

(b)

Remove the DSL solenoid valve.

CHECK:
(a)

Applying 490 kPa (5 kgf/cm

2

, 71 psi) of compressed air,

check that the solenoid valve does not leak air.

(b)

When battery positive voltage is supplied to the shift sole-
noid valve, check that the solenoid valve opens.

OK:

(a) Solenoid valve does not leak air.
(b) Solenoid valve opens.

NG

Replace the DSL solenoid valve.

OK

DI3JO–06

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–177

LEXUS RX300 (RM785E)

2

Check valve body (See page DI–160).

NG

Repair or replace the valve body.

OK

Replace the torque converter
(See page DI–192).

D01088

D03450

Automatic Transaxle

DSL Solenoid Valve

Engine & ECT ECU

+B

DSL

7

E8

R–L

3

E1

G

DI–178

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

LEXUS RX300 (RM785E)

DTC

P0773

Shift Solenoid E Electrical Malfunction
(DSLSolenoid Valve)

CIRCUIT DESCRIPTION

The DSL solenoid valve is turned ON and OFF by signals from the Engine & ECT ECU to control the hydraulic
pressure acting on the lock–up relay valve, which then controls operation of the lock–up clutch.

DTC No.

DTC Detecting Condition

Trouble Area

P0773

Either (a) or (b) are detected for 1 time.

(2 trip detection logic)

(a) Solenoid resistance is 8 Ω or less short circuit when sole-

noid is energized.

(b) Solenoid resistance is 100 kΩ or more open circuit when

solenoid is not energized.

S Open or short in DSL solenoid valve circuit

S DSL solenoid valve

S Engine & ECT ECU

Fail safe function:
If the Engine & ECT ECU detects a malfunction, it turns the DSL solenoid valve OFF.

WIRING DIAGRAM

DI0CV–13

D03727

DSL

DSL

Solenoid Connector

D03419

D03420

D03728

(–)

(+)

–

DIAGNOSTICS

AUTOMATIC TRANSAXLE

DI–179

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

1

Check harness and connector between Engine & ECT ECU and automatic trans-
axle solenoid connector (See page IN–32).

PREPARATION:
Disconnect the solenoid connector from the transaxle.
CHECK:
Check the harness and connector between terminal DSL of En-
gine & ECT ECU and terminal DSL of solenoid connector.
OK:

There is continuity.

NG

Repair or replace the harness or connector.

OK

2

Check DSL solenoid valve.

PREPARATION:
(a)

Jack up the vehicle.

(b)

Remove the oil pan.

(c)

Disconnect the DSL solenoid valve connector.

(d)

Remove the DSL solenoid valve.

CHECK:
(a)

Measure resistance between terminal DSL of solenoid
valve and solenoid body.

(b)

Connect positive lead to terminal of solenoid connec-
tor, negative lead to solenoid body.

OK:

(a) Resistance: 11 – 13 Ω
(b) The DSL solenoid valve makes operation noise.

NG

Replace the DSL solenoid valve.

OK

Check and replace or repair the solenoid
wire.