1987 MAZDA 626 engine

7C TROUBLESHOOTING
TROUBLESHOOTING
GENERAL NOTE
In the event of a problem with the automatic transaxle, the cause may be in the engine, powertrain,
hydraulic control system, or electrical control system. When troubleshooting, it is recommended to
begin from those points that can be judged quickly and easily. The recommended troubleshooting
sequence is described below.
STEP 1: PRELIMINARY INSPECTION Check preliminary items • ATF level and condition
• Oil leakage • Selector lever position
• Vacuum leakage
• Idle speed and ignition timing
• Tire inflation pressure • Inhibitor switch
This step checks conditions surrounding the automatic
transaxle.
STEP 2: STALL TEST Check engine stall speed This step checks the powertrain.
• Friction element slipping
• Torque converter capacity
STEP 3: TIME LAG TEST Check time lag of oil pressure supply This step checks operation of the hydraulic control system. • Friction elements slipping
• Regulating valves
STEP 4: ROAD TEST Check items on road test
• Shift point • Shift schedule
• Kick-down • Shift shock
This step checks functions of the electrical control system
and hydraulic control system.
STEP 5: OIL PRESSURE TEST Check line pressures and governor pressure This step checks major points of the hydraulic control system.
• Oil pump • Line pressure control • Governer pressure control
By following the above five steps, the cause of the problem should be located.
As another guide to faster location of the causes of problems, the Quick Diagnosis Chart is included
at pages 7C—9 to 7C—11.
In this chart, a circle is used to indicate the components that might be the cause of trouble for 54
types of problems. It is only necessary to check those components indicated by circles, at each step
of the troubleshooting process, in order to quickly locate the cause of the problem.
76G07C-012
7C—8

TROUBLESHOOTING
7C

QUICK DIAGNOSIS CHART
How
to use
Quick Diagnosis Chart
1.
The
numbers indicate
the
order
of
inspection
for
troubleshooting.
2. Circled numbers indicate that
the
transaxle must
be
removed from
the
vehicle.
76G07C-013
Transaxle ON VEHICLE OFF VEHICLE
•

\ Inspection point
\
and
reference
\ page
Condition


7C-25
7C-26
7C-23
10—21
7C—23,24
Section

4A

7C-14
7C—20,22
10—lb
10-12 10—69
7C—5
Section

5

7C—58
7C-62
7C-70
7C-71
7C-55
7C-125
7C-54 7C-71
7C-66,

98

7C-68,

71
\ Inspection point
\
and
reference
\ page
Condition

ATF

level
and
condition

Selector

lever
Inhibitor
switch
and
wiring

^

Vacuum
diaphragm
and

piping

|

Kick-down
solenoid,
kick-down
switch
and
wiring
Engine

idle

speed

and

condition

Engine
stall

speed

Fluid

pressure

(Line

and
governor)
Control
valves

Governor

valve
Band
servo
Transaxle
air
check
Ignition
switch
and
starter
Front
clutch

Rear

clutch
Brake

band

Low

and
reverse
brake

Oil
pump Hydraulic
circuit

Torque

converter

One-way

clutch
Parking

linkage

Planetary
gear

I

Engine

starting
Engine does
not
start
in
N or P
range •
2 3
1

Engine

starting
Engine starts
in
ranges other than
N
and P
ranges •
1 2

Accelerating
Vehicle does
not
move
in
D
range (moves
in 1, 2 & R
ranges) •
• •
•
Accelerating
Vehicle does
not
move
in
forward ranges (moves
in R
range)
Ex-
tremely poor acceleration •
• 5
• •
© •
•
• ©
•
• •
•
Accelerating
Vehicle does
not
move
in R
range (moves
in
forward range) Extremely poor acceleration 1
2 •
•
• •
•
3 4
•
• 5
• ©
© •
©
• ©
•
• •
•
Accelerating
Vehicle does
not
move
in any
range 1
2 •
•
• •
•
3 4
•
• 5
• •
• •
•
© ©
•
• ©
•
Accelerating Slippage felt when accelerating 1
2 •
6
• •
•ST
CO
•
•
• 5
• •
• •
•
© ©
•
• •
• Accelerating
Vehicle moves
in
N
range
Accelerating
Excessive creep
Accelerating
No creep
at all
©
© •
•
© ©
•
• •
•
Accelerating
Low maximum speed
and
poor acceleration 1
2 •
•
• 7
3
4 6
•
5 •
• ©
© ©

No shifting

Does
not
shift from
1
st to 2nd
•
1 •
2
3 •
•
• 4
5
6 7
• •
© ©
•
• ©
•
• •
•

No shifting
Does
not
shift from
2nd to 3rd
•
1 •
2
3 •
•
• 4
5
6 7
•

No shifting

Does
not
shift from
3rd to 2nd
1
• •
2
• •
•
• 3
4
5 6
• ©
• ©
•
• ©
•
• •
•
76G07C-014
7C-9

7C TROUBLESHOOTING
ON VEHICLE OFF VEHICLE
-

\ Inspection point
\ and reference
\ page
Condition


LO
(O
CO CJ OJ CM I
I I
O
O
CJ
r-~
r—
7C-27
7C—23,24
Section

4A

7C—14
7C—20,22
7C-75

CO
O)
in
I
I I
o
o o
r—
r—
Section

5
CO CO
o
WON I
I I
o
o o
1— 1—
m i-
in co
S
IO
i-
1
1 1
o
o o
—
I—
7C—54
7C-71
7C-66,

98

7C—68,

71
\ Inspection point
\ and reference
\ page
Condition

A.TF

level
and

condition

Selector
lever
Inhibitor
switch
and
wiring

Vacuum

diaphragm
and

piping

Kick-down

solenoid,

kick-down

switch
and

wiring

Engine

idle
speed
and
condition
Engine
stall
speed
Fluid
pressure
(Line
and
governor)

Control

valves

Governor

valve
Band
servo

Transaxle

air
check
Ignition
switch
and

starter

Front

clutch

Rear

clutch

Brake

band

Low

and
reverse
brake
Oil pump Hydraulic
circuit
Torque
converter

One-way

clutch

Parking

linkage
Planetary
gear

No
shifting

Does
not
shift from 2nd
to
1
st or from
3rd to
1
st 1
• •
2
• •
•
• 3
4
5 6
•
No
shifting

Does
not
kick-down when accelerator
is
depressed
in 3rd
within
the
kick-down range 1
• •
3
2*
•
• 4
5
• •
• •
• ©
•
• ©
•
• •
•
No
shifting
Excessive engine speed when accelerated
in 3rd
due
to
delayed kick-down 5
• 6
• ©
• •
•
• ©
•
• •
• No
shifting

Does
not
shift from
3rd to 2nd
on
D to
2
range shift 1
2 •
5
6 •
• ©
• ®
•
• ®
•
• •
•
No
shifting

Does
not
shift from
3rd to 2nd
on
D to 1
range shift 5
7 6
• ©
• ®
•
• ®
•
• •
•

Shift

shock

Excessive
N to
D
range shift shock •
• •
2
• 1
•
3 4
•
• •
• •
© •
•
• •
•
• •
•

Shift

shock

Excessive
1
st
to
2nd shift shock 1
• •
2
• •
3
• 4
•
5 6
• •
• ©
•
• •
•
• •
•

Shift

shock

Excissive 2nd
to 3rd
shift shock •
• •
1
• •
•
2 3
•
4 5
• ©
• ©

Shift

shock

Vehicle braked when shifted from
1
st
to 2nd

Shift

shock
Vehicle braked when shifted from 2nd
to 3rd
1
• •
•
• •
•
• 3
.
2 •
•

Shift

shock

Vehicle braked when shifted
to
R range 1
• •
•
• •
•
• •
•
3 2
• •
© ©
•
• •
•
• ©
•
Shift

shock

Shift shock felt when accelerator
is
released
and
deceleration occurs •
1 •
2
3*
•
4 5
6
• •
• •
• •
•
• ©
•
• *
•

Shift

shock

Excessively large 2nd
to 1st
shift shock
in 1
range 1
• •
2
• •
3
4 5
•
• •
•
Shift

point

Excessively high
1st to 2nd
and 2nd
to
3rd shift 1
• •
2
3 •
•
4 5
6
• •
•
Shift

point

Excessively high
3rd to 2nd
and
2nd to
1
st shift point •
1 •
2
3 •
•
4 5
6
• •
• •
• •
•
• ©
•
• •
•
Shift

point
Kick-down operates
or
engine overruns when depressing
ped-
al
in 3rd
beyond kick-down speed limit
1
2 •
3
• •
•
4 5
6
• 7
•

Shift
sequence

Shifts directly from 1st
to 3rd
1
• •
•
• •
•
• 2
3
• 4
• •
• ©
•
• ©
•
• •
•

Shift
sequence
Shifts from
2nd to 1st or
2nd
to
3rd
in
2
range •
1 •
•
• •
•
2 3
•
• •
•
7C-10

TROUBLESHOOTING
7C

ON VEHICLE -OFF VEHICLE
-

\ Inspection point
\
and
reference
\ page
Condition


in cd
ra
CM CM CM
I
I I
o
o o
I—
r~—
r—
7C—27
7C—23,24
Section
4A

7C—14
7C—20,22
7C-75

CM
0>
[—
CO
LO I
I I
O
O O
r^ r—
Section

5
CD CM
O
in (D
s
I
I I
o
o o
r—
r^

w
CM
r-
m f-
I
I I
o
o o
r-— I—
r-—
7C—54
7C-71
7C—66,

98

7C-68,

71 \ Inspection point
\
and
reference
\ page
Condition

ATR

level
and
condition

Selector

lever

Inhibitor

switch
and
wiring

Vacuum

diaphragm
and
piping

Kick-down
solenoid,
kick-down
switch

and

wiring

Engine

idle

speed

and
condition
Engine
stall

speed

Fluid

pressure
(Line
and
governor)
Control
valves

Governor

valve
Band
servo

Transaxle

air
check
Ignition
switch
and

starter

Front
clutch

Rear

clutch

Brake

band

Low
and

reverse

brake
Oil
pump
Hydraulic
circuit

Torque

converter

One-way

clutch
Parking
linkage

Planetary

gear

Snift
sequence

Shifts from
1st to
2nd
or
2nd
to
3rd
in 1
range

Slipping

Practically
no
shift shock,
or
slip-page while 1st
to
2nd shifting 1
2 •
3
• •
•
4 5
•
7 6
• •
• ©
•
• ©
•
• •
•

Slipping

Pracatically
no
shift shock
or
slip-page while 2nd
to
3rd shifting 1
2 •
3
• •
•
4 5
•
7 6
•

Slipping

No shift shock
or
engine runaway
in 1 to 2
range shift 1
2 •
3
• 4
5
• 6
•
• 7
• •
• ©
•
© •
•
• •
•
Slipping

Engine runaway
or
slip when shifting
3rd to 2nd
1
• •
2
• •
•
3 4
•
5 6
• ®
• ©
•
• ®
•
• •
•

Slipping

Slippage evident when vehicle starts moving 1
2 •
5
• •
•
3 4
•
• 6
• •
• •
•
® ©
•
• •
•

Noise

Transaxle noisy
in P and N
range

Noise
Transaxle noisy
in D, 2, 1 and
R ranges •
(D •
•
© •
•
© •
©

Others

No engine brake
in 1
range •
1 •
•
• •
•
2 3
•
• 4
• •
• •
©
• ©
•
• •
•

Others

Vehicle moves
in P
range
or
parking gear
not
disengaged when
P
range disengaged
•

Others
Transaxle overheats 3
4 5
•
2 6
• ®
©
(D ©
© ©
©
• •
©
Others

White smoke from exhaust while running 1
• •
2
• •
3
4 5
•
• 6
• ®
© ©
©
© ©
©
• •
@

Others

Abnormal odor from
oil
level gauge pipe ©
® ©
©
© ®
©
• •
©
76G07C-016
Differential
Problem Probable Cause Remedy Page
Noise Insufficient fluid Add 7C—25
Low fluid quality Replace with specified
ATF
7C-25
Worn bearing Adjust
or
replace 7C-79
Contact surface
of
gears worn Replace 7C-79
Tooth surface
of
gears damaged Replace 7C-79
Contaminated
ATF
Repair
or
replace 7C-25
Differential gear damaged, excessive backlash Replace 7C-79
Excessive bearing preload Adjust 7C—94
76G07C-017
7C—11

7C TROUBLESHOOTING
STEP 2 (STALL TEST)
This step is performed to determine if there is slippage of the friction elements or malfunction of the
hydraulic components.
Preparation
Check the following items prior to testing:
1. Engine coolant, engine oil and ATF levels.
2. Warm the engine thoroughly to raise the ATF temperature to operating level (50—80°C, 122—176°F).
3. Set the parking brake and block the front and rear of the wheels.
Pull the parking brake Water temperature
ATF
7C—14
76G07C-024

TROUBLESHOOTING 7C
Procedure
76G07C-025
1. Connect a tachometer to the engine.
2. Shift the selector lever to D range.
3. Depress the brake pedal firmly with the left foot, and gradually depress the accelerator pedal with
the right foot.
4. Read and note the engine speed as soon as it becomes constant; then release the accelerator pedal.
Caution
Steps 3 to 4 must be done within 5 seconds.
5. Shift the selector to N range and let the engine idle for one minute or more.
Note The idling cools the ATF and prevents oil degeneration.
6. Perform stall tests for the following ranges in the same manner.
(1) 2 range
(2) 1 range
(3) R range
Standard stall speed:
FE engine 2050—2150 rpm
F6 engine 1800—2050 rpm
Caution
Always provide adequate cooling time between individual range stall tests.
7C-15

7C TROUBLESHOOTING
Evaluation
Condition Possible cause
Worn oil pump
In all ranges Insufficient line
pressure
Oil leakage from oil pump, control
valve, and/or transaxle case
Stuck pressure regulator valve
In D, 2, and 1 Rear clutch slipping
Above specification In D range only One-way clutch slipping
In 2 range only Brake band slipping
Low and reverse brake slipping
Brake band slipping
In R range only Road test to determine if cause is low and reverse brake or reverse clutch:
a) Engine braking in 1 range Front clutch b) No engine braking in 1 range .... Low and reverse brake
Within specification All shift control elements within transaxle functioning normally
Below specification Engine out of tune Below specification
One-way clutch slipping within torque converter
76G07C-026
7C—16

TROUBLESHOOTING 7C
STEP 3 (TIME LAG TEST)
When the selector lever is shifted while the engine is idling, there is a certain time lapse, or time lag,
before shock is felt. This time lag test checks the condition of the front, rear, and one-way clutch, low
and reverse brake, and orifice check valve.
Preparation
Follow the test preparation procedure shown in STEP 2 (STALL TEST).
Procedure
1. Start the engine and verify that the idle speed is 950tso rpm.
2. Shift from N range to D range
3. Measure the time it takes from shifting until shock is felt with a stop watch.
4. Shift the selector to N range and run the engine at idle for one minute or more.
5. Perform the test for N range to R range in the same manner.
Note
Make three measurements for each test and take the average value.
Specified time lag: N D range 0.5—1.0 second
N R range 0.5—1.0 second
Evaluation
Condition Possible Cause
N -» D shift More than specification
Insufficient line pressure
N -» D shift More than specification Rear clutch slipping N -» D shift More than specification
One-way clutch slipping N -» D shift
Less than specification N-D accumulator not operating properly
N-R shift
More than specification
Insufficient line pressure
N-R shift
More than specification Low and reverse brake slipping
N-R shift
More than specification
Front clutch slipping N-R shift
Less than specification Stuck orifice check valve
N-R shift
Less than specification Excessive line pressure
76G07C-027
7C-17