Page 1008 of 1226

Automatic TransmissionlTransaxle -
Vehicles With: 4-Speed Automatic
307-01 -48 Transmission (AW81-40) 307-01 -48
DIAGNOSIS AND TESTING
Stall Speed Test
This test checks the operation of the following
components:
1
Test Results
Lower than specification in 'Dl (DRIVE) and 'R'
(REVERSE)
Lower than specification in
'Dl (DRIVE)
Lower than specification in
'R' (REVERSE)
torque converter
forward clutch
low one way clutch assembly
engine performance
Possible Source
Pressure control solenoid inoperative or open wire
harness.
Pressure regulator valve sticking.
Worn oil pump.
Oil strainer blocked.
Fluid leak from each clutch hydraulic circuit.
Drive hydraulic circuit failure.
Forward clutch failure.
Reverse hydraulic circuit failure. Reverse clutch failure.
First and reverse brake failure.
WARNINGS:
A Do not maintain wide open throttle (WOT)
in any range for more than five seconds.
A If the engine speed (rpm) recorded by the
tachometer exceeds maximum specified
rpm, release the accelerator pedal
immediately. Clutch or band slippage is
indicated.
N0TE:The stall speed test should be carried out
with the engine and transaxle at normal operating
temperatures (50°C to 80°C).
A Apply the parking brake firmly while N0TE:Prolonged use of this procedure may set
carrying out each stall test. DTC PO71 2. After carrying out the stall speed test,
A Apply the foot brake firmly while carrying run the OBD test and clear the DTCs.
out each stall test. I. Connect a tachometer to the engine.
CAUTIONS:
A Always carry out the line pressure test
before carrying out the stall speed test. If
the line pressure is low at idle, do not carry
out the stall speed test or further transaxle
damage will occur.
A After testing each of the following ranges
'D'
(DRIVE) and 'R' (REVERSE), move the
selector lever to
'N' (NEUTRAL) and run
the engine at 1000 rpm for approximately
one minute to allow the torque converter
to cool.
2. Press the accelerator pedal to the floor WOT in
each selected range. Record the rpm reached
in each selected range and refer to the stall
speed chart.
3. If the stall speed is not within specification, refer
to the stall speed diagnosis chart.
Stall S~eed Chart
I Engine 1.6L I Speed (rpm) I
I 'Dl (DRIVE) I 2500 2 150 1
'R' (REVERSE) 2420 +, 150 -
Stall
Speed Diagnosis Chart
2006.0 Fiesta 1212006 G371498en
Test Results
Lower than specification in ID' (DRIVE) and 'R'
(REVERSE)
Possible Source
Low engine power.
Torque converter one-way clutch failure.
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Page 1009 of 1226

Automatic Transmission/Transaxle -
Vehicles With: 4-Speed Automatic
307-01 49 Transmission (AW81-40) 307-01 -49
DIAGNOSIS AND TESTING
Test Results
Higher than specification in 'Dl (DRIVE)
Higher than specification in
'R' (REVERSE)
Lower than specification in 'D' (DRIVE)
Lower than specification in
'R' (REVERSE)
Possible Source
Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Forward clutch failure (slipping).
One-way clutch No.2 failure.
Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Reverse clutch failure (slipping).
First and reverse brake failure (slipping).
Drive hydraulic circuit failure.
Forward clutch failure.
Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Worn oil pump.
Oil strainer blocked.
Fluid leak from each clutch hydraulic circuit.
( Time Lag Test 1. Using a suitable stop watch, measure the time
lag three times and calculate the average time.
Time lag is the time between moving the selector Record the
time lag and refer to the time lag
lever from
IN' (NEUTRAL) to ID' (DRIVE) or IN' chart.
(NEUTRAL) to 'R' (REVERSE). With the parking 2. If the time lag is not within specification, refer
brake applied the vehicle must not move if the
to the time lag diagnosis chart.
selector lever is moved from 'N' (NEUTRAL) to
ID'
(DRIVE) or 'N' (NEUTRAL) to 'R' (REVERSE). Time Lag Chart
Drive is engaged when the vehicle starts to rise.
A WARN1NG:Apply the parking brake firmly IN' (NEUTRAL) to ID' while carrying out each test. 1 (DRIVE)
(NEUTRAL) and run the engine at 1000 rpm
for approximately
1 minute to allow the
torque converter to cool.
less than 1.0 seconds
CAUTI0N:After testing each of the
following ranges
'D' (DRIVE) and 'R'
Range
I Lower than specification in IN' (NEUTRAL) to 'Dl I Pressure control solenoid inoperative.
Ti me
(REVERSE), move the selector lever to 'N'
'N' (NEUTRAL) to 'R'
(REVERSE)
Time Lag Diagnosis Chart
(DRIVE) less
than 1.2 seconds
Test Results
Pressure regulator valve sticking.
Forward clutch failure (slipping).
Possible Source
I Timing solenoid failure.
I I Drive hydraulic circuit failure. I
2006.0 Fiesta IZIZOO~ G371498en
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Page 1010 of 1226
Automatic Transmission/Transaxle -
Vehicles With: 4-Speed Automatic
Transmission
(AW81-40)
DIAGNOSIS AND TESTING
Test Results
Lower than specification in 'N' (NEUTRAL) to 'R'
(REVERSE)
Possible Source
Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Reverse clutch failure (slipping).
First and reverse brake failure (slipping).
Reverse hydraulic circuit failure.,
(I.
2006.0 Fiesta 1212006 G371498en
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