Toyota RM787U, Руководство по обслуживанию и ремонту

Страница: 439 / 1976

DI-166
- DIAGNOSTICS AUTOMATIC TRANSAXLE
320
Author: Date:
2001 SIENNA (RM787U)
Evaluation (If N
→
D time or N
→
R time lag is longer than the specified):
Problem Possible cause
N
→
D time lag is longer
Line pressure too low
Forward clutch worn
O/D one-way clutch not operating
N
→
R time lag is longer
Line pressure too low
Direct clutch worn
1st & reverse brake worn
O/D one-way clutch not operating properly
7. 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 front left side of transaxle case and connect SST (See page
AX-22 for the location to connect SST).
SST 09992-00095 (09992-00231, 09992-00271)
(3) Fully apply the parking brake and check the 4 wheels.
(4) Connect an OBD II scan tool or TOYOTA hand-held tester to DLC3.
(5) Start the engine and check idling speed.
(6) Keep your left foot pressing firmly on the brake pedal and shift into D position.
(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 position.
Specified line pressure:
Condition D position kPa (kgf/cm
2
, psi) R position kPa (kgf/cm
2
, psi)
Idling 401 - 461 (4.1 - 4.7, 58 - 66) 804 - 882 (8.2 - 9.0, 117 - 128)
Stall 1,138 - 1,236 (11.6 - 12.6, 165 - 179) 1,716 - 1,854 (17.5 - 18.9, 249 - 269)
If the measured pressure is not up to the specified value, recheck the throttle cable adjustment and retest.
Evaluation
Problem Possible cause
If the measured values at all positions are higher
Throttle cable out of adjustment
Throttle valve defective
Regulator valve defective
If the measured values at all positions are lower
Throttle cable out of adjustment
Throttle valve defective
Regulator valve defective
Oil pump defective
O/D direct clutch defective
If pressure is low in the D position only
D position circuit fluid leakage
Forward clutch defective
If pressure is low in the R position only
R position circuit fluid leakage
Direct clutch defective
1st & reverse brake defective