1987 MAZDA 626 engine coolant

4C CONTROL SYSTEM
E/L CONTROL UNIT
Inspection
1. Connect a voltmeter between the E/L control unit
and a ground.
2. Start the engine and check the terminal voltages
as described below.
76G04C-180
Terminal Input Output Connection to Voltage (after warm-up) Remarks Terminal Input Output Connection to Ignition switch: ON Idle Remarks
A
(BW) — — Ignition switch Approx. 12V
B — — — — — —
C
(B) — — Ground OV
D (LY) O Electrical fan relay Approx. 12V Coolant temp.: below 97°C (207°F) D (LY) O Electrical fan relay
Below 1,5V Coolant temp.:
above 97°C (207°F)
E (GY) Control unit (11) OV E/L: ON E (GY) Control unit (11)
Approx. 12V E/L: OFF
F (W) O Headlight switch Approx. 12V Headlight switch:
ON F (W) O Headlight switch
Below 1,5V Headlight switch:
OFF
G (LB) o Blower motor switch Below 1.5V Blower motor switch: ON (3rd or 4th position) G (LB) o Blower motor switch
Approx. 5V Others
H
(BL) o Rear defroster
switch
Below 1.5 V Rear defroster
switch: ON H
(BL) o Rear defroster
switch Approx. 12V Rear defroster switch: OFF
76G04C-181
Replacement
1. Replace the E/L control unit.
2. Install in the reverse order of removal.
76G04C-182
4C—102

CONTROL SYSTEM 4C
WATER THERMO SENSOR
Inspection
1. Remove the water thermo sensor.
76G04C-199
86U04A-203
2. Place the sensor in water with a thermometer and
heat the water gradually.
3. Check resistance of the sensor with an ohmmeter.
Coolant Resistance
-20°C ( —4°F) 14.5—17.8 kfl
20°C ( 68°F) 2.2-2.7 kQ
40°C (104°F) 1.0—1.3 kQ
60°C (140°F) 500—640 O
80°C (176°F) 280—350 fl
4. If not correct, replace the water thermo sensor.
OXYGEN SENSOR
Inspection of Output Voltage
1. Warm up the engine and run it at idle.
2. Disconnect the oxygen sensor connector.
3. Connect a voltmeter between the oxygen sensor
and a ground.
4. Run the engine at 4,500 rpm until the voltmeter
indicates approx. 0.7V.
76G04C-200
5. Increase and decrease the engine speed suddenly
several times. Check to see that when the speed
is increased the meter reads between 0.5V—1 .OV,
and when the speed is decreased it reads between
OV—0.4V.
6. If the voltmeter dosen't indicate as specified, re-
place the oxygen sensor.
86U04A-206
4C—107

QUICK START SYSTEM (QSS) 5
SYSTEM OPERATION
The Quick Start System has three functions: Pre-heating, Chopping, and After-glow; as used in
the previous model. Each function operates as follows:
1. Pre-heating After ignition switch is turned to ON position, current flows to glow plug for 6
sec.
2. Chopping While engine switch is in START position, current flows to glow plug con-
tinuously.
3. After-glow (coolant temperature below 30°C (86°F):
a) When engine switch is kept in ON position after pre-heating, current flows to
glow plug continuously for 15 sec.
b) After engine has stared, current flows to glow plug continuously for 15 sec.
Indicator lamp: Indicator illuminates for 3 sec. after ignition is ON position.
When ignition switch is ON-START-ON position
When ignition switch is kept in ON position
76G05X-050
5-77

QUICK START SYSTEM (QSS) 5
CONTROL UNIT
Inspection
1. Connect a voltmeter to the control unit as shown
in the figure.
2. Check the voltage of the terminal.
3. Replace the control unit if necessary.
Caution
If the proper voltage is not indicated on the
voltmeter, check all wiring connections and
finally, check that component.
63G05X-337
Control Unit Connector
Terminal Input Output Connection to Operation condition Voltage Remark
for 6 sec. approx. 12V
L (GW) O Glow plug relay Engine switch: ON (No cranking) after 6 sec.
OV 12V Coolant temperature; below 30°C (86°F) after 6 sec.
OV Coolant temperature; above 30°C (86°F)
H
(B) — — Ground OV
E (BW) 0 Engine switch (ON) Engine switch: ON approx. 12V
F
(BR) O Engine switch (START) Engine switch: START approx. 12V
C o
Water
temperature switch
Engine switch: ON (No cranking)
approx. 12V Coolant temperature; below 30°C (86°F)
(BrB) o
Water
temperature switch
Engine switch: ON (No cranking)
approx. OV Coolant temperature;
above 30°C (86°F)
At cranking OV <- 12V
B 0 Glow plug
For 15 sec. after engine has started OV <-> 12V Coolant temperature;
(Gr) 0 Glow plug After 15 sec. OV below 30°C (86 °F)
After engine has started OV Coolant temperature; above 30°C (86°F)
K o Indicator Engine switch: ON
For 3 sec. OV
(WR) o Indicator Engine switch: ON after 3 sec. approx. 12V
76G05X-052
u® x y i © © X 1
© © X ®
5-79

TROUBLESHOOTING (G4A-EL) 7B
STEP 4 (STALL TEST)
This step is performed to determine if there is slippage of the friction elements or malfunction of the
hydraulic components.
Preparation
Check the following items prior to testing:
1. Engine coolant, engine oil and ATF levels.
2. Warm the engine thoroughly to raise the ATF temperature to operating level (50—80°C, 122—176°F).
3. Engage the parking brake and use wheel chocks at the front and rear wheels.
Pull the parking brake Water temperature
ATF
79G07C-084
7B-27

7B TROUBLESHOOTING (G4A-EL)
STEP 7 (ROAD TEST)
This step is performed to inspect for problems at the various ranges. If these tests show any problems,
adjust or replace by referring to the electronic system component or mechanical sections.
Caution
Perform the test at normal ATF operating temperature (50—80°C, 122—176°F).
D Range Test
Shift point, shift pattern, and shift shock
1. Shift the selector lever to D range and select the Power mode.
2. Accelerate the vehicle with half and full throttle valve opening.
Note
Throttle sensor voltage of the EC-AT Tester represents the throttle valve opening.
3. Check that 1-2, 2-3 and 3-OD up-shifts and downshifts and lock-up are obtained. The shift points
must be as shown in the D range (Power) shift diagram.
Note
a) Drum speed (rpm) of the EC-AT Tester represents the shift point.
b) Vehicle speed of the EC-AT Tester and speedometer and vehicle speed on a chassis
roller may not meet the specified shift pattern because of tire size. Therefore, check
the shift points with the Drum speed.
c) There is no lock-up when the coolant temperature is below 72°C (162°F).
d) There is no overdrive when the cruise control is operating and there is a 3 km/h (1.9
mph) difference between the pre-set cruise speed and vehicle speed, or set or resume
switch is ON.
e) There is no lock-up when the brake pedal is depressed.
4. Check the up-shifts for shift shock or slippage in the same manner.
5. While driving in OD, shift the selector lever to S range and check that 4-3 downshift immediately
occurs, then decelerate and check that engine braking effect is felt in only 3rd gear.
7B—34

TROUBLESHOOTING (G4A-HL) 7B
STEP 3 (STALL TEST)
This step is performed to determine if there is slippage of the friction elements or malfunction of the
hydraulic components.
Preparation
Check the following items prior to testing:
1. Engine coolant, engine oil and ATF levels.
2. Warm the engine thoroughly to raise the ATF temperature to operating level (50—80°C, 122—176°F).
3. Engage the parking brake and use wheel chocks at the front and rear wheels.
Pull the parking brake Water temperature
ATF
83U07B-038
7B—49

TROUBLESHOOTING (G4A-HL) 7B
STEP 5 (ROAD TEST)
This step is performed to inspect for problems at the various ranges.
If
these tests show any problems,
adjust or replace by referring to the mechanical sections.
Perform the test at normal ATF operating temperature (50—80°C, 122—176°F).
D Range Test
Shift point, shift pattern, and shift shock
1. Shift the selector lever to D range and depress the OD OFF switch.
2. Accelerate the vehicle with half (4/8) and full (8/8) throttle valve opening.
3. Check that 1-2, 2-3 and 3-OD up-shifts and downshifts and lock-up are obtained. The shift points
must be as shown in the D range shift diagram.
Note
a) Vehicle speed on a chassis roller may not meet the specified shift diagram because of
tire size.
b) There is no lock-up or OD when the coolant temperature is below 72°C (162°F), and when
the OD OFF switch is depressed.
4. Check the up and down shifts for shift shock or slippage.
5. While driving in 3rd (50—60 km/h, 31—37 mph) shift the selector lever to 2 range and check that
3-2 downshift immediately occurs, then decelerate and check that engine braking effect is felt in
2nd gear.
D range shift diagram
FE engine
Caution
8/8 n
-OD
0 20(12) 40(25) 60(37) 80(50) 100(63) 120(74) 140(87)
Vehicle speed km/h (mph)
76GC7B-057
7B—53