1987 MAZDA 626 water

4C OUTLINE
COMPONENT LOCATION
Input and Output Devices
Solenoid Solenoid Idle valve valve switch /nnA
Solenoid
valve*1 Solenoid valve*1
'(No.1 purge control)
E/L control unit
Engine control unit
Control relay
Knock sensor*2
Water thermo
switch*1
Oxygen Distributor
sensor*1
Clutch switch
\ Oxygen sensor
\ relay*1
Solenoid valve*1 (EGR)
Solenoid valve (ISC)
Air flow sensor
Neutral switch
Water thermo sensor
*1...Unleade fuel only
*2...Leaded fuel only
76G04C-004
4C—4

TROUBLESHOOTING WITH SST 4C
Malfunction display
Sensor or subsystem Self-diagnosis Fail-safe Malfunction
code no. Malfunction code output signal pattern
Sensor or subsystem Self-diagnosis Fail-safe
08
Air flow sensor Open or short circuit Maintains basic sig-nal at preset value
09 o°pNp II IIL •
Water thermo sensor Open or short circuit Maintains constant 35°C (95°F) command
11 0°FNFJUUL
Intake air thermo sensor (dynamic chamber)
Short circuit Maintains constant 20°C (68°F) command
12
Throttle sensor Open or short circuit Maintains constant command of throttle valve fully open
15 ON n
OFF •L 01
Oxygen sensor Sensor output con-tinues less than 0.55V 120 sec. after engine starts (1,500 rpm or over)
Cancels
EG I
feed-
back operation
17 ON n
OFF L HI il
Feedback system Sensor output not changed 20 sec. af-ter engine starts (1,500 rpm or over)
Cancels
EG I
feed-
back operation
25 0°nfJU1LJIL
Solenoid valve (pres-sure regulator control)
Open or short circuit
26 2LMJIL
Solenoid valve (No.1 purge control)
Open or short circuit
27 ON nn
OFF | _ •111
-ii-Solenoid valve (No.2
purge control)
Open or short circuit
28 ON nn
OFF L Hi nr
Solenoid valve (EGR)
Open or short circuit
34 ^jmiHum
Solenoid valve (Idle speed control)
Open or short circuit
36 °FFJMI«U
Oxygen sensor relay
Open or short circuit
41 <£jimjiuM
Solenoid valve (Vari-able inertia control)
Open or short circuit
76G04C-018
Caution
a) If there is more than one failure present, the lowest number malfunction code is dis-
played first, the remaining codes are displayed sequentially.
b) After repairing a failure, turn off the ignition switch and disconnect the negative battery
cable and depress the brake pedal for at least 5 seconds to erase the memory of a mal-
function code.
4C—15

4C TROUBLESHOOTING WITH SST
Is there continuity between air flow sensor and
engine control unit?
Air flow sensor Engine control unit
D (RB wire) 2E
E (RW wire) 2B
NO
YES
Is there 12V at terminal B of air flow sensor connector? (Refer to page 4C—103)
YES
Is there continuity between terminal F of air flow sensor and ground? (Refer to page 4C-103)
YES
NO
NO
PC: Open circuit in wiring harness
PC: Open or short circuit in wiring harness from terminal B to control relay
PC: Open circuit in wiring harness
PC: • Engine control unit malfunction • Short circuit in wiring from terminal D of air flow sensor to engine control unit
76G04C-022
Code No. 09 (Water thermo sensor)
Are there poor connections in water thermo sensor circuit?
NO
Is there continuity between water thermo sensor and engine control unit?
YES
Is resistance of the water thermo sensor OK? Resistance:
YES
Water thermo sensor Enaine control unit
A (YB wire) 21
B (LgY wire) 2C
NO
Coolant temp Resistance
-20°C ( —4°F) 14.5-17.8 kfl
20°C ( 68°F) 2.2- 2.7 kfi
40°C {104°F) 1.0- 1.3 kfi
60°C (140°F) 500-640 fi
80°C (176°F) 280-350 fi
NO
YES
Is same Code No. present after performing after-repair procedure? (Refer to page 4C—12)
YES
Are engine control unit 21 and 2C terminal voltages OK? (Refer to page 4C—98)
YES
NO
NO
PC: Possible Cause
Repair or replace connector
PC: Open circuit in wiring harness from water thermo sensor to engine control unit
Replace water thermo sensor
Water thermo sensor and circuit OK
PC: Short circuit in wiring harness
PC: Engine control unit malfunction
76G04C-023
4C—18

SWITCH MONITOR FUNCTION 4C
SWITCH MONITOR FUNCTION
Individual switches can be monitored by the SST (Self-Diagnosis checker 49 G018 9A0 or Digital
code checker 49 9200 180).
Note
The test connector must be grounded and the ignition switch ON (engine stopped).
Engine control unit
76G04C-035
Switch Self-Diagnosis Checker (Monitor lamp) Remark Switch Light ON Light OFF Remark
Clutch switch Pedal released Pedal depressed In gear
Neutral switch In gear Neutral Clutch pedal released
Idle switch Pedal depressed Pedal released —
Headlight switch ON OFF —
Rear defroster switch ON OFF —
Blower switch ON OFF Blower motor position: "3" or "4"
Water thermo switch (Elec-trical fan) Terminal disconnected Terminal connected While fan not operating
4C—25

4C SWITCH MONITOR FUNCTION
Water thermo switch circuit
76G04C-043
4C-28

4C INTAKE AIR SYSTEM
REMOVAL
Caution
Before removing the following parts, release the fuel pressure from fuel system to reduce
the possibility of injury or fire. (Refer to page 4C—52.)
Remove in the sequence shown in the figure, referring to the removal note.
1. Air cleaner
2. Air flow sensor
3. Air hoses
4. Connectors (Idle switch,
ISC, Throttle sensor)
5. Water hoses
6. Vacuum hoses
7. Accelerator cable
8. Throttle body
9. Gasket
10. PCV hose
4C-32
11. Vacuum pipe assembly
(Unleaded fuel)
12. Dynamic chamber brackets
13. Connectors (Knock sensor,
Intake air thermo sensor)
14. Dynamic chamber
15. One-way check valve
16. Gasket
17. Wiring harness
(for injectors)
18. Fuel hoses
76G04C-053
19. Delivery pipe assembly
mounting bolt.
20. Heat insulator
21. Injectors
22. Delivery pipe assembly
23. EGR pipe
24. Intake manifold bracket
25. Solenoid valve
26. Intake manifold
27. Gasket
28. Air duct
29. Resonance chamber

INTAKE AIR SYSTEM 4C
76G04C-054
76G04C-055
76G04C-056
Removal Note
Water hose
Before disconnecting the water hose, drain two liters
of engine coolant.
Delivery pipe assembly.
1. Separate the fuel return pipe from the delivery pipe
assembly.
2. Remove the delivery pipe assembly and the fuel
return pipe.
PARTS INSPECTION
Air Cleaner Element
1. Check the condition of the air cleaner element.
2. Blow out the dust with compressed air, if
necessary.
Caution
a) The air cleaner must be replaced at the in-
tervals outlined in the maintenance
schedule.
b) Never drive the vehicle without the air
cleaner element, otherwise, damage to the
air flow sensor (hot wire) will occur.
c) Never use an oil permeated air cleaner ele-
ment, otherwise, contamination of the hot
wire will occur.
4C—33

4C INTAKE AIR SYSTEM
Installation Note
Water hose spring clamps
Face the clamp end as shown in the figure.
Gasket
Use new gaskets at the intake manifold, dynamic
chamber, and throttle body.
86U04A-056
• . v 1
Engine 1 Ml' ' •-
hanger ^ •
• i::£?^Solenoid valve bracket
Air cleaner. r^I. ^jUvW;
Th V
Ground harnesses
Make sure that the ground harnesses are tightened
securely at the following positions.
(1) Air cleaner upper case
(2) Solenoid valve braket
(3) Engine hanger
76G04C-062
Solenoid valve connectors
Connect the solenoid valve connectors at the posi-
tions shown in the figure.
76G04C-063
Inspection after installation
1. After completing installation, fill up the engine with
the specified engine coolant.
2. Warm up the engine and run it at idle.
3. Check for any vacuum, coolant, or fuel leaks.
76G04C-064
4C-38