1987 MAZDA 626 brake sensor

FUEL AND EMISSION
CONTROL SYSTEMS
(FUEL INJECTION FE)
OUTLINE 4B— 2
SYSTEM DIAGRAM 4B— 2
COMPONENT LOCATION 4B— 3
VACUUM HOSE ROUTING
DIAGRAM 4B— 5
SPECIFICATIONS 4B— 6
TROUBLESHOOTING GUIDE 4B— 7
TROUBLESHOOTING
PROCEDURE 4B— 7
TROUBLESHOOTING WITH SST.... 4B— 9
INSPECTION PROCEDURE 4B—10
AFTER-REPAIR PROCEDURE 4B—10
PRINCIPLE OF CODE CYCLE 4B—12
CODE NUMBER 4B—13
SWITCH MONITOR FUNCTION 4B—25
INSPECTION PROCEDURE 4B—26
IDLE SPEED 4B—29
IDLE MIXTURE 4B—29
INTAKE AIR SYSTEM 4B—30
COMPONENT DESCRIPTIONS 4B—30
REMOVAL 4B—31
PARTS INSPECTION 4B—32
INSTALLATION 4B—34
IDLE-UP SYSTEM 4B—35
COMPONENT DESCRIPTIONS 4B—36
TROUBLESHOOTING 4B—37
AIR VALVE 4B—38
AIR BYPASS SOLENOID VALVE ... 4B—39
FUEL SYSTEM 4B—42
COMPONENT DESCRIPTIONS 4B—43
TROUBLESHOOTING 4B—44
FUEL PRESSURE RELEASE AND
SERVICING FUEL SYSTEM 4B—45
MULTI-PRESSURE TESTER 4B—46
FUEL PRESSURE 4B—48
FUEL PUMP 4B—49
PULSATION DAMPER 4B—50
INJECTOR 4B—51
PRESSURE REGULATOR
CONTROL SYSTEM 4B—53
COMPONENT DESCRIPTIONS 4B—54
TROUBLESHOOTING 4B—55
REPLACEMENT 4B—57
FUEL TANK 4B—61
DECELERATION CONTROL
SYSTEM 4B—64
COMPONENT DESCRIPTIONS 4B—65
TROUBLESHOOTING 4B—66
AIR INJECTION SYSTEM 4B—68
COMPONENT DESCRIPTIONS 4B—68
TROUBLESHOOTING 4B—69
EXHAUST GAS RECIRCULATION
(EGR) SYSTEM 4B—71
COMPONENT DESCRIPTIONS 4B—71
TROUBLESHOOTING 4B—72
EVAPORATIVE EMISSION
CONTROL (EEC) SYSTEM 4B—74
COMPONENT DESCRIPTIONS 4B—74
TROUBLESHOOTING 4B—75
POSITIVE CRANKCASE
VENTILATION (PCV) SYSTEM 4B—80
COMPONENT DESCRIPTION 4B—80
EXHAUST SYSTEM 4B—81
REMOVAL AND INSTALLATION ... 4B—82
INSPECTION 4B—82
CONTROL SYSTEM 4B—83
RELATIONSHIP CHART 4B—84
EGI MAIN FUSE 4B—86
MAIN RELAY 4B—86
CIRCUIT OPENING RELAY 4B—86
ENGINE CONTROL UNIT 4B—87
NEUTRAL SWITCH 4B—91
CLUTCH SWITCH 4B—91
BRAKE LIGHT SWITCH 4B—91
P/S PRESSURE SWITCH 4B—92
INHIBITOR SWITCH 4B—92
E/L CONTROL UNIT 4B—93
AIR FLOW METER 4B—94
THROTTLE SENSOR 4B—95
WATER THERMO SENSOR 4B—97
WATER THERMO SWITCH 4B—97
OXYGEN SENSOR 4B—98
ATMOSPHERIC PRESSUFfE
SENSOR 4B—99
76G04B-001

TROUBLESHOOTING GUIDE 4B
TROUBLESHOOTING GUIDE
This troubleshooting guide shows the malfunction numbers and the symptoms of various failures.
Perform troubleshooting as described below.
Possible cause
Symptom
Input sensors and switches
o> Q.
C
0
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4B-14
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E
o
4B-1S
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0 <0 £
4B-16
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a>
.x
co
4B-17
o 10 c a) co
4B-18
o in c a> (0
o> o> a>
a) £ a VI o E
4B-19
0 <0 c a> 0) c a> 01
S? o
4B-20
E a> in (0
o 10 A •o 0) 0> u.
4B-21
Output solenoid valves
o «
3 O) 0)
0) 0) 01
0> > 10 >
•o o c V o tt)
4B-22
0)
OI

0> > CO >

TJ
O c 0> o CO
4B-23
oc O u
o> > 75 >
•o o c a> o 05
4B-23
0 a. 3 1
2
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"D O
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4B-23
ffl a 3 • a>
2
a> > 10 >
"O o c a> o
CO Q. >. JO
4B-24
Fault Indicated by SST
Code No. 01 08 09 10 12 14 15 17 25 26 28 34 35
Hard start or won't start
(Cranks OK)
Engine stalls
Rough
idle
While warming up
After warming up
While warming up
After warming up
High idle speed after
warming up
TROUBLESHOOTING PROCEDURE
Note
Step 1 under symptom is to quickly determine what system or unit may be at fault by use of the SST. (Self-Diagnosis Checker 49 H018 9A1)
1st:
Check input sensors and output solenoid valves with the
SST.
(Refer
to
page 4B—10.)

2nd:
Check other switches with the
SST.
(Refer
to
page 4B—26.)

3rd:
Check the following items:

11
Poor acceleration, hesita-
tion or lack of power
Runs rough on deceleration
Afterburn in exhaust system
Poor fuel consumption
Engine stalls or rough after hot starting
Electrical system
1) Battery condition
2) Fuses

Fuel system
1) Fuel level 2) Fuel leakage
3) Fuel filter 4) Idle speed

Engine
1) Compression 2) Overheating

Ignition system

1) Ignition spark 2) Ignition timing

Intake air system
1)
Air
cleaner element 2) Vacuum
or air
leakage 3) Vacuum hose routing
4) Accelerator cable

Others
1) Clutch slippage 2) Brake dragging

Fails emission test 4th:
Check Fuel and Emission Control Systems. (Refer
to
page 4B—8.)

76G04B-003
4B—7

TROUBLESHOOTING WITH SST 4B
CODE NUMBER
Malfunction display
Self-diagnosis Fail-safe Code
No. Output signal pattern subsystem Self-diagnosis Fail-safe

01
ON
OFF

Ignition pulse
No ignition signal
08
Air flow meter
Open
or
short circuit
Maintains basic sig-
nal
at
preset value
09
1 111

Water thermo sensor
Open
or
short circuit
Maintains constant command 35°C (95 °F)
10
Intake
air
thermo sensor (air flow meter) Open
or
short circuit
Maintains constant 20°C (68°F) command
12
£_IUILJIIL

Throttle sensor
Open
or
short circuit
Maintains constant
command
of
throttle
valve fully open
14
OFF
TL
I I nil

Atmospheric pres-
sure sensor Open
or
short circuit
Maintains constant command
of
sea level pressure
15
oTp m 11 [U

Oxygen sensor Sensor output con-tinues less than 0.55V 120 sec. after engine starts (1,500 rpm)
Cancels EG
I
feed-
back operation
17
SLJlMJl

Feedback system Sensor output
not
changed
20
sec.
af-
ter engine exceeds 1,500 rpm
Cancels EGI feed-back operation
25
^JMLJl

Solenoid valve (pres-
sure regulator)
Open
or
short circuit
26
SUUBUIL

Solenoid valve (purge control)
Open
or
short circuit 28
£ mi in nr

Solenoid valve
(EGR) Open
or
short circuit
34
^jmiUTT

Air bypass solenoid
valve (Idle-up
C)

Open
or
short circuit
35
0Nnnnj OFFU u UUU
"fin nnr
Air bypass solenoid
valve (Idle-up
B)

Open
or
short circuit

76G04B-008
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 2 seconds to erase the memory of a mal-
function code.
4B-13

DECELERATION CONTROL SYSTEM 4B
COMPONENT DESCRIPTIONS
Component Function Remarks
Brake light switch Detects braking operation (deceleration);
sends signal to engine control unit
Clutch switch Detects in-gear condition;
sends signal to engine control unit Switch ON when clutch pedal released
Dashpot (MTX) Prevents sudden closing of throttle valve during deceleration or shifting Adjustment speed: 1,900—2,100 rpm
Engine control unit Detects signals from input sensors and switches; cuts fuel injection
Idle switch Detects when throttle valve fully closed; sends signal to engine control unit Installed in throttle sensor
Ignition coil (-) terminal Detects engine speed; sends signal to engine control unit
Neutral switch Detects in-gear condition; sends signal to engine control unit Switch ON when in-gear
Water thermo sensor Detects coolant temperature; sends signal to engine control unit
Water thermo switch Detects radiator coolant temperature; sends signal to engine control unit ON: above 17°C (63°F)
76G04B-089
4B—65

CONTROL SYSTEM 4B
CONTROL SYSTEM
Atmospheric
pressue sensor
Engine control unit
Brake light switch
Clutch switch
Circuti opening
relay
E/L control unit
Air flow meter
Neutral switch
76G04B-129
The control system consists of the input devices and the engine control unit. The engine control unit
controls the fuel injection amount (EGI), fuel injection pressure, bypass air amount, switch monitor func-
tion, and fail-safe function.
4B—83

4B CONTROL SYSTEM
RELATIONSHIP CHART
Input Devices and Output Devices
BRAKE LIGHT SWITCH O X X X X X X X X X
ELECTRICAL LOAD CONTROL UNIT X X X X X X X X O X
P/S PRESSURE SWITCH* X X X X X X X X O X
A/C SWITCH O X X X X O O X X O
IGNITION SWITCH
(STA

POSITION) O O X O X X X X O O
INHIBITOR SWITCH o X X X O X X X X O
NEUTRAL
AND
CLUTCH SWITCH o X X X X X X X X O
OXYGEN SENSOR o X X X X X X X X X
WATER THERMO SWITCH (RADIATOR) o X X X O X X X X X
ATMOSPHERIC PRESSURE SENSOR o X X X X O X O O X
INTAKE
AIR
THERMO SENSOR o X X O X X X O O X
WATER THERMO SENSOR o X X O O O X X o X
IDLE SWITCH o o X O X X X X o X
THROTTLE SENSOR o O X X O X X X X O
AIR FLOW METER o X X X X O X X X X
IGNITION COIL o O X O O O X X o O

INPUT
DEVICES
OUTPUT
DEVICES
FUEL
INJECTION
AMOUNT FUEL
INJECTION

TIMING
PRESSURE
REGULATOR
EGR
PURGE
IDLE-UP
(A)*
IDLE-UP
(B)

IDLE-UP

(C)

rr

INPUT
DEVICES
OUTPUT
DEVICES
INJECTOR
AIR

VALVE
SOLENOID
VALVE
AIR

BYPASS
SOLENOID
VALVE
AIR

CONDITIONEI

76G04B-108
4B-84

TROUBLESHOOTING GUIDE 4C
TROUBLESHOOTING GUIDE
This troubleshooting guide shows the malfunction numbers and the symptoms of various failures.
Perform troubleshooting as described below.
Input sensors and switches
Possible cause
Page
Symptom and No. CO
T O
a c OI '35
O
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o in
a> in
8 c
o
o (A C 0) in
S o
I o
c $
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00 T-I O
T o I-ij
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2 a
o>
o
e o •C H
I O
o at e 0) o>
o CM I o
E a> «-» in >• in a o (0 A •o a> d>
CM I o
Output solenoid valve
o> > <0 >
2
—.

§8 £ c
O O
(0
O

CVI I o
c 0 u « 01 w 3 a
o z «
> 73 >
"O o c a> o (/)
CM CM
o
O o 0) o>
Q. CM
V >
CB >
•o o c 4) o CO
CM CM
O
oc (9 UJ, g
n >
•o o c a> o <0
CO CM
O
o o •o w « a in «
2
s
5 •o o c »
o CO
CO CM
o
n
£
o in c a* (A c a> o>
o
CM
O
w q) t « s > c w QJ O)
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a >
T3 O C ai o CO
TT CM
o
Fault Indicated by SST
Code No. 02 03 05 *i 08 09 11 12 *2 15 • 2 17 *2 25 26 *2 27 *2 28 • 2 34 36 • 2 41
Hard start or won't start
(Cranks OK)
Engine stalls
Rough
Idle
During warm up
After warm up
During warm up
After warm up
High idle speed after warm up
Poor acceleration, hesita-tion or lack of power
TROUBLESHOOTING PROCEDURE
Note
Code No. Is to quickly determine which system or unit may be at fault by use of the SST. (Self-Diagnosis Checker 49 H018 9A1 or Digital Code Checker 49 G018 9A0 with Adaptor harness 49 9200 180)
1st: Check input sensors and output solenoid valves with the SST. (Refer to
page
AC—11.)

2nd: Check other switches with the SST. (Refer to page AC—25.)
3rd: Check the following items:
Electrical system
1) Battery condition 2) Fuses
Runs rough on deceleration
Afterburn in exhaust
system
9
10
Poor fuel consumption
Engine stalls or runs
rough after hot starting
11
12
Knocking
Fuel system
1) Fuel level
2) Fuel leakage 3) Fuel filter 4) Idle speed (with test connec-tor grounded)
Engine
1) Compression 2) Overheating
Ignition system 1) Ignition spark
2) Ignition timing (with test connec-tor grounded)
Intake air system 1) Air cleaner element 2) Vacuum or air leakage 3) Vacuum hose routing 4) Accelerator cable
Others 1) Clutch slippage
2) Brake dragging
Fails emission test 4th: Check Fuel and Emission Control Systems. (Refer to page 4C—10.)
*1..
*2„
.Leaded fuel
.Unleaded fuel
76G04C-009
4C—9

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