1987 MAZDA 626 temperature

4A CONTROL SYSTEM
ENGINE CONTROL UNIT
Check the engine control unit terminal voltages with
a voltmeter.
Caution
a) Warm up the engine before checking the
control unit.
b) If the proper voltage is not obtained, check
the wiring, connections and finally, check
the component.
FE and F8 Engine — ATX (ECE, Hong Kong, and Singapore)
Terminal
(Wire color) Connected to Condition Voltage

1A
(BW)
Ignition switch Ignition switch ON. Battery voltage

m
ST
'-O
Solenoid valve (Main
air
bleed control) Others Battery voltage
m
ST
'-O
Solenoid valve (Main
air
bleed control) Radiator coolant temperature below 17°C (63°F)
or
intake manifold vacuum more than 200 mmHg (7.9 inHg)
Below 1,5V
1C (GO) Solenoid valve (Choke opener) Radiator coolant temperature below 17°C (63°F)
or
during cranking and
27
sec. after engine starts Below 1,5V
Others Battery voltage
1D
(GL)
Air bypass solenoid valve Idle switch OFF and engine speed above approx. 2,100 rpm Below 1,5V
Others Battery voltage
1E
— — —

1F
(G) Solenoid valve (Ignition timing control system)
Radiator coolant temperature above 17°C (63°F),
en-
gine coolant temperature below 72°C (162°F), inhibi-tor switch OFF and engine speed below 2,300
rpm

Below 1.5 V
Others Battery voltage
1G
— — —

1H
(LW) Solenoid valve (A/C) A/C switch
ON
and engine speed below approx. 2,300
rpm

Below 1,5V
Others Battery voltage
11
(YW) Idle-up solenoid valve Inhibitor switch OFF and, headlight switch ON, rear
defroster switch ON, fan speed control switch
is 3rd

or 4th position, A/C operated,
or
engine coolant tem-
perature below 72°C (162°F)
Below 1,5V
Others Battery voltage
1J
(B)
Ground
—
Below 1,5V

9 MSSirSl
ivj
A 1
k *
76G04A-169
4A—86

CONTROL SYSTEM 4 A
Terminal
(Wire color) Connected to Condition Voltage

2A
(YL)
Ignition coil Ignition switch
ON or
engine running Battery voltage
2B (LB) Fan speed control switch Fan speed control switch
in
3rd
or
4th position Below 1.5 V 2B (LB) Fan speed control switch
Fan speed control switch OFF Battery voltage
2C
(BL)
Rear defroster switch Rear defroster switch
ON
Below 1,5V 2C
(BL)
Rear defroster switch
Rear defroster switch OFF Battery voltage
2D
(LG)
A/C switch A/C operated Below 1,5V 2D
(LG)
A/C switch
A/C not operated Battery voltage
2E
(RG)
Headlight switch Headlight switch OFF Below 1.5 V 2E
(RG)
Headlight switch
Headlight switch
ON
Battery voltage
2F
(GW)
Water thermo switch
(Radiator)
Radiator coolant temperature below 17°C (63°F) Below 1.5V 2F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature above 17°C (63°F) Battery voltage
2G
-— —

2H
(L)
Water thermo switch (In-
take manifold)
Engine coolant temperature below 72°C (162°F) Below 1,5V 2H
(L)
Water thermo switch (In-
take manifold) Engine coolant temperature above 72°C (162°F) Battery voltage
21
(LY)
Vacuum switch Vacuum less than 200 mmHg (7.9 inHg) Below 1.5V 21
(LY)
Vacuum switch
Vacuum more than 200 mmHg (7.9 inHg) Battery voltage
2J (RL) OD release solenoid valve Engine coolant temperature below 72°C (162°F) Below 1.5V 2J (RL) OD release solenoid valve
Engine coolant temperature above 72°C (162°F) Battery voltage
2K
(-)

— — -

2L (BR)
Inhibitor switch "N"
or "P"
range Below 1.5V 2L (BR)
Inhibitor switch
Others Battery voltage
2M (BY) Ignition switch
(START position)
Ignition switch
ON
Below 1,5V 2M (BY) Ignition switch
(START position) Cranking Battery voltage
2N
(LsB) Idle switch Idling Battery voltage 2N
(LsB) Idle switch
Accelerator pedal depressed Below 1,5V

76G04A-170

{ 2M 2K 21
X
2F 2C
2A

2N 2L 2J 2H 2F 2D 2B
(11 X X
1C 1 A^j
1J 1H 1F 1D 1B

FE and F8 Engine — MTX (ECE, Hong Kong, and Singapore)
Terminal (Wire color) Connected to Condition Voltage

A
(RG) Headlight switch Headlight switch
ON
Below 1,5V A
(RG) Headlight switch
Headlight switch OFF Battery voltage
B
(B)
Ground
—
Below 1,5V

4A-87

4A CONTROL SYSTEM
Terminal (Wire color) Connected to Condition Voltage

C (BL) Rear defroster switch Rear defroster switch
ON
Below 1,5V C (BL) Rear defroster switch
Rear defroster switch OFF Battery voltage
D
(LG) A/C switch A/C operated Below 1,5V D
(LG) A/C switch
A/C not operated Battery voltage
E (LY) Solenoid valve (Main
air
bleed control) Intake manifold vacuum more than 300 mmHg (11.8 inHg), and radiator coolant temperature above 17°C (63 °F)
Battery voltage E (LY) Solenoid valve (Main
air
bleed control)
Others Below 1,5V
F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature below 17°C (63°F) Below 1,5V F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature above 17°C (63°F) Battery voltage
G (YL)
Ignition coil Ignition switch
ON or
engine running Battery voltage
H
(L)
Water thermo switch (Intake manifold) Engine coolant temperature below 72°C (162°F) Below 1,5V H
(L)
Water thermo switch (Intake manifold) Engine coolant temperature above 72°C (162°F) Battery voltage
J (BW) Ignition switch Ignition switch
ON
Battery voltage
K (GO) Solenoid valve (Choke opener) Radiator temperature below 17°C (63°F)
or
during cranking and
27
sec. after engine starts Below 1,5V K (GO) Solenoid valve (Choke opener)
Others Battery voltage
L (LsB) Idle switch Idling Battery voltage L (LsB) Idle switch
Accelerator pedal depressed Below 1,5V
M
(GL)
Air bypass solenoid valve Idle switch OFF and engine speed above approx. 2,100 rpm Below 1,5V M
(GL)
Air bypass solenoid valve
Others Battery voltage
0
(BY)
Ignition switch
(START position)
Ignition switch
ON
Below 1,5V 0
(BY)
Ignition switch
(START position) Cranking Battery voltage
P
(LW) Solenoid valve (A/C) A/C switch
ON
and engine speed below approx.
2,300
rpm

Below 1,5V P
(LW) Solenoid valve (A/C)
Others Battery voltage
Q (YW) Idle-up solenoid valve Headlight switch ON, rear defroster switch ON,
fan
speed control switch
is
3rd
or
4th position, A/C oper-ated,
or
engine coolant temperature below 72°C (162°F)
Below 1,5V Q (YW) Idle-up solenoid valve
Others Battery voltage
R
(LB)
Fan speed control switch Fan speed control switch
in
3rd
or
4th position Below 1,5V R
(LB)
Fan speed control switch
Fan speed control switch OFF Battery voltage

76G04A-171

f ° O M K I G E C
R P N L J H F D B

4A-88

CONTROL SYSTEM 4 A
FE and F8 Engine — ATX (General)
Terminal (Wire color) Connected to Condition Voltage

1A
(BW)
Ignition switch Ignition switch
ON
Battery voltage
1B (GR) Solenoid valve (Main
air
bleed control) Others Battery voltage 1B (GR) Solenoid valve (Main
air
bleed control) Radiator coolant temperature below 17°C (63°F)
or
intake manifold vacuum more than 200 mmHg (7.9 inHg)
Below 1,5V
1C
— — —

1D
— — —

1E
— — —

1F
— --

1G
-—

1H
(LW) Solenoid valve (A/C) A/C operated Below 1,5V 1H
(LW) Solenoid valve (A/C)
Others Battery voltage
11
(LW) Idle-up solenoid valve Inhibitor switch OFF and, headlight switch ON, rear defroster switch ON, fan speed control switch
is 3rd
or 4th position, A/C operated,
or
engine coolant tem-perature below 72°C (162°F)
Below 1,5V 11
(LW) Idle-up solenoid valve
Others Battery voltage
1J
(B)
Ground
—
Below 1.5V
2A (YL) Ignition coil Ignition switch
ON or
engine running Battery voltage
2B (LB) Fan speed control switch Fan speed control switch
in
3rd
or
4th position Below 1.5V 2B (LB) Fan speed control switch
Fan speed control switch OFF Battery voltage
2C
(BL)
Rear defroster switch Rear defroster switch
ON
Below 1,5V 2C
(BL)
Rear defroster switch
Rear defroster switch OFF Battery voltage
2D
(LG) A/C switch A/C operated Below 1,5V 2D
(LG) A/C switch
A/C not operated Battery voltage
2E
(RG)
Headlight switch Headlight switch
ON
Below 1,5V 2E
(RG)
Headlight switch
Headlight switch OFF Battery voltage
2F
(GW)
Water thermo switch
(Radiator)
Radiator coolant temperature below 17°C (63°F) Below 1.5V 2F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature above 17°C (63°F) Battery voltage
2G
— — —

2H
(L)
Water thermo switch
(Intake manifold) Engine coolant temperature below 72°C (162°F) Below 1,5V 2H
(L)
Water thermo switch
(Intake manifold) Engine coolant temperature above 72°C (162°F) Battery voltage
21 (LB)
Vacuum switch Vacuum less than 200 mmHg (7.9 inHg) Below 1.5V 21 (LB)
Vacuum switch
Vacuum more than 200 mmHg (7.9 inHg) Battery voltage
2J
(RL)
OD release solenoid Engine coolant temperature below 72°C (162°F) Below 1,5V 2J
(RL)
OD release solenoid
Engine coolant temperature above 72°C (162°F) Battery voltage

4A-89

4A CONTROL SYSTEM
Terminal
(Wire color) Connected to Condition Voltage

2K
— — —

2L
(BR) Inhibitor switch "P"
or "N"
range Below 1,5V 2L
(BR) Inhibitor switch
Others Battery voltage
2M
(BY)
Ignition switch
(START position)
Ignition switch
ON
Below 1,5V 2M
(BY)
Ignition switch
(START position) Cranking Battery voltage
2N
— — —
76G04A-172
(2M X
2
X
2F 2C

X 2L
2J 2H 2F 2D 2B

fll X >< X

1J 1H
>< X
1B

FE and F8 Engine — MTX (General)
Terminal (Wire color) Connected to Condition Voltage

A
(W)
Headlight switch Headlight switch
ON
Below 1,5V A
(W)
Headlight switch
Headlight switch OFF Battery voltage
B
(B)
Ground
—
Below 1,5V
C
(BL) Rear defroster switch Rear defroster switch
ON
Below 1,5V C
(BL) Rear defroster switch
Rear defroster switch OFF Battery voltage
D
(LG) A/C switch A/C operated Below 1.5V D
(LG) A/C switch
A/C not operated Battery voltage
E
(LB) Solenoid valve (Main
air

bleed control)
Intake manifold vacuum more than 300 mmHg (11.8 inHg), and radiator coolant temperature above 17°C (63 °F)
Battery voltage E
(LB) Solenoid valve (Main
air

bleed control)
Others Below 1.5V
F
(GW)
Water thermo switch
(Radiator)
Radiator coolant temperature below 17°C (63°F) Below 1,5V F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature above 17°C (63°F) Battery voltage
G (YL)
Ignition coil Ignition switch
ON or
engine running Battery voltage
H
(L)
Water thermo switch (Intake manifold) Engine coolant temperature below 72°C (162°F) Below 1,5V H
(L)
Water thermo switch (Intake manifold) Engine coolant temperature above 72°C (162°F) Battery voltage
I
— — —

J
(BW)
Ignition switch Ignition switch
ON
Battery voltage
K
— —

L
— — —

M
— — —

N
— —
4A-90

CONTROL SYSTEM 4 A
Terminal (Wire color) Connected to Condition Voltage

0 (BY)
Ignition switch*
(START position) Ignition switch
ON
Below 1.5V 0 (BY)
Ignition switch*
(START position) Cranking Battery voltage
P
(LW) Solenoid valve (A/C) A/C switch
ON
and engine speed below approx.
2,300
rpm
Below 1,5V
Others Battery voltage
Q (YW) Idle-up solenoid valve Headlight switch ON, rear defroster switch ON,
fan
speed control switch
is
3rd
or
4th position, A/C oper-ated,
or
engine coolant temperature below 72°C (162°F)
Below 1,5V
Others Battery voltage
R
(LB)
Fan speed control switch Fan speed control switch
in
3rd
or
4th position Below 1,5V R
(LB) Fan speed control switch OFF Battery voltage
*
Not
used
76G04A-173

{
Q
0
><
K
X
G E C A
^

R P
R X
J H F D B

FE 8Valve — Unleaded Fuel
Terminal (Wire color) Connected to Condition Voltage

A
(L)
Coast enrichment solenoid valve Engine speed approx. 1,500—2,300 rpm and idle switch
ON

Below 1,5V A
(L)
Coast enrichment solenoid valve
Others Battery voltage
B
(B)
Ground
—
Below 1,5V
C (LB)
Air bypass solenoid valve Engine speed above approx. 3,500 rpm and idle
switch
ON

Below 1,5V C (LB)
Air bypass solenoid valve
Others Battery voltage
D
(YL)
Ignition coil Ignition switch
ON or
engine running Battery voltage
E
— — —

F
(BW)
Ignition switch Ignition switch
ON
Battery voltage
G (YW) Slow fuel cut solenoid valve Engine speed above approx. 2,300 rpm and idle
switch
ON

Battery voltage G (YW) Slow fuel cut solenoid valve
Others Below 1.5V
H
(LW) A/C switch A/C operated and engine speed above approx.
1,500 rpm
Battery voltage H
(LW) A/C switch
A/C not operated
or
engine speed below approx.
1,500 rpm
Below 1,5V

4A—91

4B IDLE-UP SYSTEM
COMPONENT DESCRIPTIONS
Component Function Remarks
Air bypass solenoid
valve

Controls bypass
air
amount Operates A: A/C
: ON

B: Intake
air
temp, high
or at
high
al-
titude C: P/S
:
ON, E/L applied
or
hot start

Air valve
When cold, supplies bypass
air
into
dy-

namic chamber
• Engine speed increased
to
shorten
warm-up period
• Bimetal type

Atmospheric pressure sensor

Detects atmospheric pressure; sends sig-
nal
to
engine control unit

E/L control unit
Detects electrical load applied; sends sig-nal
to
engine control unit

Engine control unit
Detects signals from input sensors and switches; controls
air
bypass solenoid valve

Intake air thermo sensor
Detects intake
air
temperature; sends sig-
nal
to
engine control unit
Installed
in air
flow meter

P/S pressure switch
Detects P/S operation; sends signal
to
engine control unit P/S:
ON
when steering wheel turnefl right
or
left

76g04b-044
4B-36

4B IDLE-UP SYSTEM
AIR VALVE
Pre-inspection
1. Start the engine and run it at idle.
2. Pinch the bypass air hose and check that the en-
gine rpm drops.
When engine still cool RPM reduced
After warming-up RPM drop within
200 rpm
3. If the speed is not reduced when cold, check the
air valve, or check for vacuum leaks at the bypass
air hose.
4. If the speed drop is more than 200 rpm when
warm, check the air valve and current to the valve.
Inspection of Terminal Voltage
1. Disconnect the connector from the valve.
2. Remove the rubber boot from the connector.
3. Start the engine and run it at idle.
4. Check that there is battery voltage at terminal (WY),
using a voltmeter.
5. If not correct, check the circuit opening relay and
wiring harness.
76G04B-046
Inspection of Air Valve
1. Check the valve for operation.
Temperature 20°C (68°F) Valve open
(When engine cool)
After warming-up Valve closed
2. Replace valve if faulty.
76G04B-047
4B—38 expert22 Arm http://rutracker.org