TM-270
< ON-VEHICLE MAINTENANCE >
[5AT: RE5R05A]
INSPECTIONS BEFORE TROUBLE DIAGNOSIS
Judgment Possible
cause
Idle speed
Low for all positions
(P, R, N, D)
Possible causes include malfunctions in the pressure supply system and low oil pump output.
For example
• Oil pump wear
• Pressure regulator valve or plug sticking or spring fatigue
• Oil strainer
⇒
oil pump
⇒
pressure regulator valve passage oil leak
• Engine idle speed too low
Only low for a spe-
cific position
Possible causes include an oil pressure leak in a passage or device related to the position after
the pressure is distributed by the manual valve.
High
Possible causes include a sensor malfunction or malfunction in the line pressure adjustment func-
tion.
For example
• Accelerator pedal position signal malfunction
• ATF temperature sensor malfunction
• Line pressure solenoid malfunction (sticking in “OFF” state, filter clog, cut line)
• Pressure regulator valve or plug sticking
Stall speed
Oil pressure does
not rise higher than
the oil pressure for
idle.
Possible causes include a sensor malfunction or malfunction in the pressure adjustment function.
For example
• Accelerator pedal position signal malfunction
• TCM breakdown
• Line pressure solenoid malfunction (shorting, sticking in“ ON” state)
• Pressure regulator valve or plug sticking
• Pilot valve sticking or pilot filter clogged
The pressure rises,
but does not enter
the standard posi-
tion.
Possible causes include malfunctions in the pressure supply system and malfunction in the pres-
sure adjustment function.
For example
• Accelerator pedal position signal malfunction
• Line pressure solenoid malfunction (sticking, filter clog)
• Pressure regulator valve or plug sticking
• Pilot valve sticking or pilot filter clogged
Only low for a spe-
cific position
Possible causes include an oil pressure leak in a passage or device related to the position after
the pressure is distributed by the manual valve.