1987 MAZDA 626 Workshop Manual

ELECTRICAL COMPONENTS OF 4-WHEEL STEERING 1 0
Warning light output pattern Malfunction Flow chart No.
ON
ncc
Stepper motor or wiring harness 4WS—6 Stepper motor or wiring harness 4WS—6
ON
r\cc
Oil leakage or oil
level switch
4WS—7 Oil leakage or oil
level switch
4WS—7
ON
OFF
Control unit 4WS—8 Control unit 4WS—8
ON
ncc
Control unit, alter-nator, or wiring harness
4WS—9
ON
ncc
Control unit, alter-nator, or wiring harness
4WS—9 Control unit, alter-nator, or wiring harness
4WS—9
86U10X-226
10—97

1 0 ELECTRICAL COMPONENTS OF 4-WHEEL STEERING
4WS-0 Normal operation or failure of con-trol unit or harness
Start engine.
Disconnect R-01 (7-pin) connector. Check that 4WS warning light flashes or illuminates.
NG
Repair harness. (Fuse box to Control unit or Control unit to Body ground).
YES No electrical problem.
NO
Reconnect connector.
Check voltage between terminals and body ground.
Terminal Voltage
G(B) OV
H(B) OV
K(G) Approx. 12V
L(G) Approx. 12V
N(B) OV
OK Replace control unit.
4WS-1 Failure of speed sensors or wiring
harness
Check speed sensor at transaxle. (Referring to page 10—103)
OK
NG Replace speed sensor.
Check for continuity between terminal of transaxle speed sensor and R (O) terminal of the control unit connector.
NG^ Repair wiring harness (Control unit to Transaxle
speed sensor).
Cont'd 76G10X-028
10—98

ELECTRICAL COMPONENTS OF 4-WHEEL STEERING 1 0
OK
Replace control unit.
Flashes or
Illuminates
Replace rear steering gear assembly.
4WS-3 Failure of solenoid valve or harness
Disconnect R-01 (17-pin) connector. Check voltage between terminals and body ground with ignition switch ON. OK
Terminal Voltage
E(R) Approx. 12V
F(RY) Approx. 12V

J
NG
Disconnect solenoid valve connector. Check for con-
tinuity between terminals on valve side.
Terminals continuity
GR — RY Yes
GY — R Yes
NG
Replace solenoid valve unit.
Replace control unit.
OK Repair harness (Fuse box to Solenoid valve or Sole-noid valve to Control unit).
76G10X-029
10—99

1 0 ELECTRICAL COMPONENTS OF 4-WHEEL STEERING
awq a Failure of stepper motor or harness
Disconnect R-01 (17-pin) connector. Check for no
continuity between each terminal of harness side
connector and body ground.
NG
Disconnect stepper motor connector. Check for no
continuity between each terminal and body ground.
Terminal Continuity
NG
Terminal Continuity
A (WB) No NG WB No
B (WL) No WL No
C (WR) No WR No
D (WY) No WY No
L(G) No G No
OK , OK | NG OK
Repair harness (Step-
per motor to Control
unit).
Replace rear steering
gear assembly.
Check for continuity between terminals of R-01
(17-pin) harness side connector.
NG
Disconnect stepper motor connector. Check for con-tinuity between terminals of motor side connector.
Terminal Continuity NG Terminals Continuity
A (WB) - L (G) Yes NG WB — G Yes
B (WL) — L (G) Yes
NG
WL — G Yes
C (WR) — L (G) Yes
NG
WR — G Yes
D (WY) — L (G) Yes
NG
WY — G Yes
NG
OK OK | NG
Replace control unit. Repair wiring harness (Stepper motor to Con-trol unit).
Replace rear steering gear assembly.
Repair wiring harness (Stepper motor to Con-trol unit).
Replace rear steering gear assembly.
4WS-5 Failure of rear to front steering ra-
tio sensor
Go to 4W5-2
76G10X-046
10-100

ELECTRICAL COMPONENTS OF 4-WHEEL STEERING 1 0
4WS-6 Failure of rear to front steering ra-tio sensor or harness
Start engine.
I
Check voltage between control unit terminal and body ground.
OK
Check voltage between control unit terminal and body ground.
Terminal Resistance
2F (GO) Approx. 5.0 V
NG Replace control unit.
Terminal Resistance
2G (GW) Approx. 4.5 V
OK Replace control unit.
NG
Check rear to front ratio sensor (Refer to page 10-103).
NG Replace rear steering gear assembly
OK
Repair harness (Control unit to Sensor).
Flashes or illuminates
Check voltage between 0(Y) terminal of R-01 (17-pin)
connector and a body ground.
Terminal Voltage
0(Y) 0 V
OK Replace control unit.
NG
10-101

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.