engine MAZDA 626 1987 Workshop Manual

1 0 ELECTRICAL COMPONENTS OF 4-WHEEL STEERING
flashes
Replace control unit
4WS-9 Failure of control unit, alternator, or wiring harness
Start engine,
I
Check voltage between terminal of control unit con-nector and body ground.
Terminal Voltage
G(B) OV
H (B) OV
K(G) Approx. 12V
L (G) Approx. 12V
N(B) OV
OK
NG
Check 4WS relay and timer (Refer to page 10—103) -
OK
Check battery, harness, and alternator.
NG
Turn ignition switch OFF. Start engine. Check if 4WS warning light flashes or illuminates.
NO
Momentary problem (If warning light often flashes or illuminates, check battery and alter-nator. Replace control unit if necessary).
YES
Replace control unit.
Replace relay and timer
76G10X-031
4WS WARNING LIGHT
1. Turn the ignition switch OFF.
2. Turn the ignition switch ON, and check that the
4WS warning light illuminates.
3. If there is no illumination, check the warning light
bulb and wiring harness.
Replace the control unit if necessary.
86U10X-232
10-102

ELECTRICAL COMPONENTS OF 4-WHEEL STEERING 1 0
SPEED SENSOR (IN METER)
1. Jack up the front of the vehicle.
2. Connect a voltmeter between 2A (GR) terminal of
the control unit connector and a body ground.
3. Start the engine. Check that periodic voltage is de-
tected when turning'the front wheels slowly.
4. If periodic voltage is not detected, check the wir-
ing harness. Replace the speed sensor if
necessary.
86U10X-233
SPEED SENSOR (AT TRANSAXLE)
1. Jack up the front of the vehicle.
2. Connect a voltmeter between R (O) terminal of the
control unit connector and a body ground.
3. Start the engine. Check that periodic voltage is de-
tected when turning the front wheels slowly.
4. If periodic voltage is not detected, check the wir-
ing harness. Replace the speed sensor if
necessary.
86U10X-234
REAR-TO-FRONT STEERING RATIO SENSOR
Check the resistance between the terminals with an
ohmmeter.
Terminal [ Resistance
GB—GO l 3.5—6.5 kfi
GB—GW ' 3.2—5.9 kfi

If
the resistance is not within specification, replace the
rear steering gear assembly.
86U10X-235
OIL LEVEL SWITCH (IN P/S RESERVOIR)
Check for continuity of the switch with an ohmmeter.
Fluid level Continuity
More than L No
Less than L Yes

If
the continuity is not within specification, replace the
P/S reservoir.
86U10X-236
10—103

1 0 ELECTRICAL COMPONENTS OF 4-WHEEL STEERING
86U10X-237
76G10X-047
10—104
RELAY AND TIMER
1. Start the engine.
2. Check voltage between each terminal of the relay
and timer connector and a body ground.
Terminal Voltage
a 12V
b 12V
d 12V
i 12V
1 OV
If the voltage is not as specified, replace the fuse
or repair the harness.
3. Check voltage between each terminal and a body
ground with the engine running.
Terminal Voltage
f 12V
h 12V
4. Check that the voltage of f and h terminal is 12V
for approximately 7 to 10 seconds after the igni-
tion switch is turned OFF.
If not, replace the relay and timer.

POWER BRAKE UNIT 1 1
86U11X-038
0
o
X
\ V^ Third
Second
^ First
86U11X-039
O X

fiSy

V
86U11X-040
Pedal-depression Pre!tur!9au9e
force gauge
^Intake manifold
86U11X-041
POWER BRAKE UNIT
FUNCTION CHECK
Simple Method
First step
1. With the engine stopped, depress the pedal a few
times.
2. With the pedal depressed, start the engine
3. If immediately after the engine starts the pedal
moves down slightly, the unit is operating.
Second step
1. Start the engine.
2. Stop the engine after it has run for
1
or 2 minutes.
3. Depress the pedal with the usual force.
4.
If
the first pedal stroke is long and becomes short-
er with subsequent strokes, the unit is operating.
5. If a problem is found, inspect for damage of the
check valve or vacuum hose, and examine the in-
stallation condition. Repair if necessary, and inspect
it once again.
Third step
1. Start the engine.
2. Depress the pedal with the usual force.
3. Stop the engine with the pedal still depressed.
4. Hold the pedal down for about 30 seconds.
5. If the pedal height does not change, the unit is
operating.
6. If there is a problem, check for damage to the
check valve or vacuum hose, and check the con-
nection. Repair if necessary, and check once
again.
If the nature of the problem is still not clear after fol-
lowing the 3 steps above, follow the more detailed
check described in "Method using tester".
Method Using Tester
Connect a pressure gauge, vacuum gauge, and ped-
al depression force gauge as shown in the figure. Af-
ter bleeding the air from the pressure gauge, conduct
the test as described in the 3 steps below.
Note
Use commercially available gauges and ped-
al depression force gauge.
11—27

1 1 POWER BRAKE UNIT
a) Checking for vacuum loss
Unloaded condition
1. Start the engine.
2. Stop the engine when the vacuum gauge reading
reaches 500 mmHg (19.7 inHg).
3. Observe the vacuum gauge for 15 seconds.
If
the
gauge shows 475—500 mmHg (18.7—19.7
inHg), the unit is operating.
76G11X-065
Loaded condition
1. Start the engine.
2. Depress the brake pedal with a force of 196 N (20
kg, 44 lb).
3. With the brake pedal depressed, stop the engine
when the vacuum gauge reading reaches 500
mmHg (19.7 inHg).
4. Observe the vacuum gauge for 15 seconds.
If
the
gauge shows 475—500 mmHg (18.7—19.7
inHg), the unit is operating.
76G11X066
b) Checking for hydraulic pressure
1. If with the engine stopped (when vacuum is 0
mmHg) the relation between pedal force and fluid
pressure is within specification, the unit is operating.
Pedal force Fluid pressure
196 N (20 kg, 44 lb) | 1,177 kPa (12 kg/cm2, 171 psi) mia
76G11X-067
2. Start the engine. Depress the brake pedal when
the vacuum reaches 500 mmHg (19.7 inHg).
If the relation between pedal force and fluid pres-
sure is within specification, the unit is operating.
Pedal force Fluid pressure
196 N (20 kg, 44 lb) 7,063 kPa (72 kg/cm2, 1,024 psi) min.
76G11X068
11-28

POWER BRAKE UNIT 1 1
76G11X-034
INSPECTION OF CHECK VALVE
Note (MTX)
The check valve is pressed into the vacuum
hose. There is an arrow on the hose surface
to indicate direction of installation.
Inspection
1. Disconnect the vacuum hose from the engine.
2. Apply suction and pressure to the hose from the
engine side. Check that air flows only toward the
engine.
If the air passes in both directions or not at all, re-
place the check valve (along with the hose).
REMOVAL
Remove in the sequence shown in the figure, referring to removal note for specially marked parts.
1. Fluid level sensor connector
2. Vacuum switch coupler
(RF, RF-CX)
3. Brake pipe
4. Master cylinder
5. Clutch pipe holder
6. Vacuum hose and check
valve
7. Clevis pin
8. Steering shaft
76G11X-069
9. Power brake unit
10. Gasket
11. Locknut
12. Operating lever
11-29

VACUUM PUMP 1 1
VACUUM PUMP
1. Disconnect the vacuum hose and release the re-
maining vacuum.
2. Connect a vacuum gauge as shown in the figure.
3. Run the engine at idle speed.
Idle speed: 720 1 20 rpm
4. Check that the vacuum reaches 500 mmHg (19.7
inHg) in 8 seconds or less.
5. Check that the maximum vacuum is within approx.
700—720 mmHg (27.6—28.3 inHg) in 80 sec-
onds or less.
REMOVAL AND INSTALLATION
1. Remove in the sequence shown in the figure.
2. Install in the reverse order of removal, referring to installation note for specially marked parts.
Note
The engine oil will leak out when disconnecting the oil hose. Prepare a suitable container
for it to drain into.
76G11X-038
76G11X-037
1. Vacuum hose
2. Oil return hose
3. Oil inlet hose
4. Drive velt cover
5. Vacuum pump

PARKING BRAKE 1 1
86U11X-130
86U11X-131
PARKING BRAKE
ON-VEHICLE MAINTENANCE
Parking Brake Lever Stroke
Inspection
Check that the stroke is within specification when the
parking brake lever is pulled with a force of 98N
(10kg, 22lb).
Stroke: 5—7 notches
Adjustment
1. Before adjustment, start the engine and depress
the brake pedal several times.
2. Stop the engine.
3. Remove the adjust nut clip and turn the adjust nut
at the front of the parking cable.
4. After adjustment, check the following points:
(1) Turn the ignition switch ON, pull the parking
brake lever one notch, and check that the park-
ing brake warning lamp illuminates.
(2) Check that the rear brakes do not drag.
11—65

ANTI-LOCK BRAKE SYSTEM (ABS) 1 1
TROUBLESHOOTING
Precaution
Conditions that are not malfunctions
1. It may happen that vibration is felt in the steering wheel, body, and/or brake pedal when the ABS
is functioning; such vibration is simply an indication that the system is functioning.
2. Sound of the pump motor operating, accumulator pressure being released, or the relay operating
may be heard from the engine compartment when the engine is started as the system is being auto-
matically checked.
3. The ABS pump motor may be automatically activated even though the ABS is not operating.
4. The ABS warning light may illuminate under any of the following conditions:
• When the vehicle is traveling on snow or ice with the parking brake activated or a brake dragging
at one wheel.
• When different-sized tires are used.
• When tires of different gripping performance are used.
• When (while the vehicle is jacked up or stuck) only the front wheels are spun for 20 seconds or more.
• When there is insufficient battery voltage.
Note
Under the above conditions, the warning light will not illuminate a second time when the
ignition is switched OFF then back ON, and there will be no memory entry to the control
unit of a problem.
Troubleshooting notes
The ABS is composed of electrical components, mechanical components (hydraulic unit), and the com-
ponents of the standard brake system.
Fundamentally, malfunction of the ABS electrical or mechanical components is judged by the self-
diagnosis function within the ABS control unit. And malfunctions are indicated by the warning light
in the instrument panel.
The location
of
a malfunction is indicated by the technician switching the system to the diagnosis-indication
mode.
The self-diagnosis and indication functions must be used when malfunctions of the ABS are being
diagnosed.
76G11X-091
11—73

1 1 ANTI-LOCK BRAKE SYSTEM (ABS)
Troubleshooting Main Flow Chart
Check that the ABS warning light operates.

• Turn ignition switch OFF
to
ON, and check that ABS warning light illuminates constantly.

Flashing (Past failure)
OK
Check the ABS for failure.
• Start engine, and observe flashing
of
warning light.
Does not
illuminate
constantly
Warning light Possible cause
Does
not il-

luminate
at all

Refer
to
page 11—86.

ON
Alternator
L
ter-minal output Wiring harness (ALT-control unit) Control unit

OFF
1 sec

Alternator
L
ter-minal output Wiring harness (ALT-control unit) Control unit

ON
Relay box wiring harness (warning light-control unit) Control unit

OFF
1 sec

Relay box wiring harness (warning light-control unit) Control unit

No illumination
(Not diagnosed)
Illuminates constantly
(Present failure)
ABS is usually operating cor-rectly.
Consult table below when ABS failure
is
still suspected.
System Possible cause
ABS Brake light switch
Both rear wheel speed sensors
Control unit Proportioning
valve
in hy-
draulic unit
Other than Refer
to

ABS troubleshoot-ing guide
on

page 11—5.

Repair failures with flow
chart. (Refer to page
11—76.)
76G11X-054
11-74