Subaru 2009 IMPREZA Service Manual page 1888

AUTOMATIC TRANSMISSION
13) Perform the stall tests with the select lever in
"D" range.
NOTE:
• Do not continue the stall test for 5 seconds or
more at a time (from closed throttle, fully open
throttle to stall speed reading). Failure to follow this
instruction will cause the engine oil and ATF to de-
teriorate and the clutch and brake to be adversely
affected.
• Be sure to cool down the engine for at least one
minute after each stall test with the select lever set
in the "P" or "N" range and with the idle speed of
1,200 rpm or less.
• If the stall speed is higher than the specified
range, attempt to finish the stall test in as short a
time as possible, in order to prevent the automatic
transmission from sustaining damage.
Stall speed (at sea level):
Non-turbo model
2,200 — 2,700 rpm
Turbo model
2,800 — 3,300 rpm
Stall speed (at sea level)
Below specified value
Over specified value
Stall Test
Range
2nd gear on manual mode, R
D
R
2nd gear of manual mode
4AT-32
Cause
• Throttle valve is not fully open
• Engine malfunction
• One-way clutch of the torque converter is slipping
• Line pressure too low
• Low clutch slipping
• One-way clutch malfunctioning
• Line pressure too low
• Reverse clutch slipping
• Low & reverse brake slipping
• Line pressure too low
• Low clutch slipping
• 2-4 brake slipping