wheel MAZDA 626 1987 Workshop Manual

ELECTRICAL COMPONENTS OF ELECTRONICALLY-CONTROLLED POWER STEERING (ECPS) 1 0
Diagnosis Table
Condition Output pattern Malfunction Flow chart
No.
4.4V
0V-
10 seconds Power steering sole-noid valve or wiring harness (Control unit to Solenoid valve)
P/S—1
Refer to page
10-91
4.4V
0V-
Wiring harness (Con-
trol unit to Ignition coil) P/S—2 Refer to page 10-91
Steering wheel in straight-ahead po-sition with engine idling.
4.4V
OV-
Steering wheel angle sensor or wiring har-ness (Control unit to Angle sensor)
P/S—3 Refer to page 10-92
4.4V
ov-
Normal operation
Wiring harness (Fuse box to Control unit or Control unit to Body ground)
P/S—5 Refer to page 10—93
OV
10 seconds Power steering sole-
noid valve or wiring
harness (Control unit
to Solenoid valve)
P/S—1 Refer to page 10—91
B Steering wheel turned 45° left and right from center with engine idling
4.4V
0V
Wiring harness (Con-
trol unit to Ignition coil)
P/S—2 Refer to page 10-91
4.4V
0V'
Normal operation
4.4V
0V-
Steering wheel angle
sensor or wiring har-
ness (Control unit to
Angle sensor)
P/S—3 Refer to page 10—92
76G10X-023
10-89

1 0 ELECTRICAL COMPONENTS OF ELECTRONICALLY-CONTROLLED POWER STEERING (ECPS)
Condition Output pattern Malfunction Flow chart No.
B Cont'd
OV
Wiring harness (Fuse
box to Control unit or
Control unit to Body
ground)
P/S—5 Refer to page 10-93
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
4.4V —
1 3 s econds Power steering sole-noid valve or wiring harness (Control unit to Solenoid valve)
P/S—1 Refer to page 10-91
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
uv
Power steering sole-noid valve or wiring harness (Control unit to Solenoid valve)
P/S—1 Refer to page 10-91
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
4.4V
n\i
—
Wiring harness (Con-trol unit to Ignition coil) P/S—2 Refer to page 10-91
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
Wiring harness (Con-trol unit to Ignition coil) P/S—2 Refer to page 10-91
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
4.4V
Steering wheel angle sensor or wiring har-ness (Control unit to Angle sensor)
P/S-3 Refer to page 10—92
C
Front wheels driv-en at more than 10 km/h (6.2 mph)

V
Steering wheel angle sensor or wiring har-ness (Control unit to Angle sensor)
P/S-3 Refer to page 10—92
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
4.4V
Vehicle speed sensor or wiring harness
(Control unit to Meter)
P/S—4 Refer to page 10-92
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
uv
Vehicle speed sensor or wiring harness
(Control unit to Meter)
P/S—4 Refer to page 10-92
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
4.4V
OV —
Normal operation —
C
Front wheels driv-en at more than 10 km/h (6.2 mph)
OV
Wiring harness (Fuse box to Control unit or Control unit to Body ground)
P/S—5 Refer to page 10-93
76G10X-024
10-90

1 0 ELECTRICAL COMPONENTS OF 4-WHEEL STEERING
ELECTRICAL COMPONENTS OF 4-WHEEL STEERING (4WS)
CIRCUIT DIAGRAM
2 UJ I- >-CO -I o CC I-z o o „
0 uoipas)
''R cc ~~w josuas paads oi
=
8<--0 D—S
--0 D-* H 8
--0
D--S
l-S
s-U
0
s g~o 5-s
S--0 D~°
'-HH J
D-c
>-[In
J—0 &-c

1
Note
Refer to page 10—31 for component location.
86U10X-221
10—94

ELECTRICAL COMPONENTS OF 4-WHEEL STEERING 1 0
TROUBLESHOOTING GUIDE
Self-Diagnosis Function
The four-wheel steering (4WS) control unit contains a self-diagnosis function to detect malfunctions
within itself, the 4WS electrical components and circuits.
If a malfunction is detected, the control unit indicates where the problem is located and the 4WS warn-
ing light in the instrument cluster will flash for one minute with a specific pattern,
Troubleshoot the 4WS system according to the following flow chart.
Symptom of problem
76G10X-026
TROUBLESHOOTING
Checking Condition
Condition A
1. Turn the ignition switch OFF.
2. Start the engine after the ignition switch has been
OFF for at least 10 seconds, and check if the 4WS
warning light flashes or illuminates within 60
seconds.
3.
If
flashing or illumination occurs, inspect the circuit.
(Refer to page 10—95.)
76G10X-027
10—95

1 0 ELECTRICAL COMPONENTS OF 4-WHEEL STEERING
Condition B
1. Place the vehicle on a chassis roller tester. Block
the rear wheels, and secure it with chains.
2. Turn the ignition switch OFF.
3. Start the engine after the ignition switch has been
OFF for at least 10 seconds. Put the transmission
in gear and operate the vehicle at more than 40
km/h (25 mph).
4. Check if the 4WS warning light flashes or il-
luminates within 60 seconds.
5.
If
flashing or illumination occurs, inspect the circuit
by referring to the table below.
76G10X045
Diagnosis Output Pattern
Warning light output pattern
0.5 sec —i 2.5 sec
Malfunction
Normal operation, control unit or wir-ing harness
Speed sensors or
wiring harness
Flow chart
No.
4WS—0
4WS—1
Rear steering gear
assembly
Solenoid valve or wiring harness
Stepper motor or wiring harness
Rear-to-front steer-ing ratio sensor or wiring harness
4WS—2
4WS—3
4WS—4
4WS—5
86U10X-225
10-96

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