1992 MAZDA PROTEGE fuel

F SELF-DIAGNOSIS FUNCTION
Troubleshooting
If a service code number is show on the SST, check for the cause by using the chart related to the code
number shown.
r c :ODE No. -
iTEl
I 02 (DISTRIBUTOR Ne-SIGNAL)
INSPECTION I
ACTION
1
1
2
Check if Code No.03 is also present
-5- Check terminal-wire for continuity
4
Check if battery voltage exists at distributor
terminal-wire
-i-- Check terminal-wire between distributor and
ECU terminal 2E (MTX) 2A (ATX) for continuity
and ground
6
Cl$c; ,if$CU terminal 2E (MTX) 2A (ATX) volt- Yes Replace ECU
w page F-149
w page F-152 . No
Go to next step
7
I I
Check if OV or 45V--55V exists at distributor 1 Yes 1 Reolace distributor I
8
- Check distributor circuit for poor connection Yes
1 I Repair or replace connector
I
No SOHC
Go to Step 3
DOHC
Go to next step
Yes Go to next step I
No Go to Step 5
Yes
I I Go to next step
I
No
I I
Repair or replace
Yes Go to next step
No Check for open circuit in wiring from
distributor to main relay (FUEL INJ
relay)
Yes Go to next step
No Repair or replace
terminal-wire (W)
No Go to next step
Check if 4.5V-5.5V exists at ECU terminal 2E
(MTX) 2A (ATX) (With distributor connector dis-
connected) Yes Check for short circuit in wiring from
distributor to ECU
No Replace ECU CT page F-149
.-I 4
F-86

SELF-DIAGNOSIS FUNCTlON F
I
ECU
Ne-SIGNAL
Circuit Diagram
MTX
30A MAIN RELAY
Cl IEl Ihl I ra)El A”
B/W ,, ,, B/w ,, m/W ,/ +,J@ , ““l”
\ IF \ ,,
ff W Y/L
II f
II II $4
BlLG
WIG I ___ --- -i-
((
I*
- & W/R
B
t B.
DISTRIBUTOR
ATX
r
ECU
Ne-SIGNAL
MAIN RELAY .
w-w
(FUEL INJ RELAY) w-w
WIR
23UOFX-O!
F-87

SELF-DIAGNOSIS FUNCTION F
I ECU
Circuit Diagram
MTX
1
G-SIGNAL
30A
MAIN RELAY
(FUEL INJ RELAY)
BIW ,, ,, lBiW ,, BIVJ,,
W/R
\ // 1,
Y/L
WIG --- s-v ---
--w v-s
SlLG
IL--;) I/ 4
DISTRIBUTOR
23UOFX-05
ATX
ECU
G-SIGNAL
MAIN RELAY
(FUEL INJ RELAY)
WIG
WIR
DISTRISUTOR
F-89

SELF-DIAGNOSIS FUNCTION
:ODE No. 17 (Oxygen sensor-lnvarsion)
r t
INSPECTION
Check if same Code No. is present after per-
forming after-repair procedure CT- page F-704
Check monitor lamp of Self-Diagnosis Checker il-
luminate at idle after warming-up engine and
running it at 2,500-3,000 rpm
for 3 minutes
Check for correct fuel line pressure at idle CT page F-129
Fuel line pressure;
265-314 kPa (2.7-3.2 kg/cm2, 38-46 psi)
{Vacuum hose to pressure regulator
disconnected)
4 Check injectors for fuel teakage c3 page F-132
5
Disconnect each high-tension lead at idle and
check if engine speed decreases equally at each
cylinder
Circuit Oiagram
MTX
I ACTION
Yes 1 Go to next step NO
Check oxygen sensor circuit for poor
connection
r3 If OK, perform troubleshooting
Code No.15
a
If not OK, repair or replace con-
nector u page F-98
Yes Go to next step Note
l A/F mixture rich
No
I Go to Step 5 Note
l A/F mixture is lean or misfire
occurring
Yes
I Go to next step No High pressure
Check if fuel return hose is ciogged or
restricted
+ If OK, replace pressure regulator CT page F-130
c3 If not OK, repair or replace
Yes Replace injector
No Check if water thermosensor is OK
ti if OK, Go to Step 11
c3 If not OK, replace water thermo-
sensor c7 page F-168
CT page F-168
Yes
Go to next step No
Go to Step 8
23UOFX-07
OXYGEN SENSOR
I
R/L
ECU
----------h--M
23UOFX-074
F-l 00

SELF-DIAGNOSIS FUNCTION F
TEP
6
7
8
9
IO
11 INSPECTION
Check for correct fuel line pressure at idle
IV page F-122
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm’, 38-46 psi)
(Vacuum hose to pressure regulator
disconnected)
Check intake air system components for air
leakage
Check for misfire of dead cylinder from Step 5
inspection
Check for injector operating sound at idle of
dead cylinder from Step 5 inspection -
Replace injector at dead cylinder from Step 5 in-
spection
CI page F-131
Check if same Code No. is present following
performing after-repair procedure
CT page F-104
Try known good ECU and check if condition
Improves
CT page F-149 Yes
No
Yes If not clogged, check fuel pump
maximum pressure
Go to Step 11
No Replace
--
Yes Repair or replace ignition system
No
Yes
No
Yes
No
T L ACTION
Go to next step
Low pressure
Check fuel line pressure while pinching
fuel return hose
~3 If fuel line pressure quickly in-
creases, check pressure regulator
v page F-129
c3 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
CT page F-126
Go to next step
Go to next step
Check for battery voltage at injector
connector terminal-wire (W/R)
L3 If Yes, replace injector c7 page F-131
+ If No, check wire harness for short
or open
Go to next step
Removed injector at fault
Circuit Diagram
ATX
OXYGENSENSOR
R/L
ECU
-------------- ---
BILG
23UOFX-07
F-10'

SELF-DIAGNOSIS FUNCTION
:ODE No. 1 25 (SOLENOID VALVE - PRESSUREREGULATORCONTROL)-BPENGINE
r (
TEP
1
-
2
-
3 I
INSPECTION
Disconnect connector from ECU and check if
battery voltage exists at ECU terminal 2T (MTX)
3M (ATX) wire (G/O) with ignition switch ON
In same condition as Step 1, check if battery
voltage exists at solenoid valve connector
terminal-wire (G/O) ACTION
Yes Check ECU terminal connector for poor -
connection
* If OK, replace ECU CT page F-149
+
If not OK, repair or replace connector
No Go to next step
Yes Repair or replace wire (G/O)
No Go to next step
Check if solenoid valve is OK Yes Check for short or open circuit in wiring
w page F-135 from main relay (FUEL INJ relay) to
solenoid valve
No Replace solenoid valve
I I I
23UOFX-077
:ODE No. 26 (SOLENOID VALVE - PURGE CONTROL)
STEP INSPECTION
Disconnect connector from ECU and check if
battery voltage exists at ECU terminal 2X (MTX)
20 (ATX) wire harness (W/L) with ignition switch
ON Yes
No
In same condition as Step 1, check if battery
Yes
voltage exists at solenoid valve connector
terminal-wire (W/L)
No
Check if solenoid valve is OK
Yes
w page F-140
t- No
--
4 ACTION
Check ECU terminal connector for poor
connection
ti If OK, replace ECU c;p page F-149
e
If not OK, repair or replace connector
Go to next step
Repair or replace wire harness (W/L)
Go to next step
Check for short or open circuit in wiring
from main relay (FUEL INJ relay) to
Circuit Diagram
MTX
I-
FROM
BATTERY
FROM
23UOFX-07 9
F-l 02

SELF-DIAGNOSIS FUNCTION F
1
CODE No. 34 (ISC VALVE)
1 ACTION
Yes Check ECU terminal connector for poor
connection INSPECTION
Disconnect connector from ECU and check if
battery voltage exists at ECU terminal 2W (MTX)
3Q (ATX) wire (L/O) with ignition switch ON
c3 If OK, replace ECU
+ If not OK, repair or replace con-
nector w page F-149
No Go to next step
In same condition as Step 1, check if battery
voltage exists at ISC valve connector terminal.
wire (L/O) Yes ) Repair or replace wire (L/O)
No Go to next step
Yes Check for short or open circuit in wiring
from main relay (FUEL INJ relay) to ISC
valve
No Replace ISC valve Check ISC valve for correct resistance
w page F-i 16
Resistance: 1 l-130 [at 20°C(68”F) ]
I 23UOFX-08( I
r C :ODE No. )
41 (SOLENOID VALVE - VICSbDOHC
I
ii
T
I
INSPECTION
ACTION
Check ECU terminal connector for poor
connection
in’
I
* If OK, replace ECU w page F-149
c3 If not OK, repair or replace con-
nector
No Go to next step Disconnect connector from ECU and check if
battery voltage exists at ECU
terminal 2S (MTX)
31 (ATX) wire (B/R) with ignition switch ON
2 In same condition as Step 1, check if battery voltage exists at solenoid valve connector
terminal-wire (B/R)
Check if solenoid valve is OK
w page F-l 18 Yes Repair or replace wire (B/R)
No Go to next step
Yes Check for short or open circuit in wiring
from main relay to solenoid valve
No
Replace solenoid valve
23UOFX-081 3
Circuit Diagram
ATX
ISC VALVE
FROM
BATTERY 4
FROM
L
IGNITION d++n.D,,
SWITCH
MAIN RELAY
(FUEL INJ RELAY) S
4\ ECU
SOLENOID VALVE
i(VICS) [DOHC]
W/R ,,
\
SOLENOID VALVE ,
(PURGE CONTROL)
23UOFX-082
F-i 03

F FUEL SYSTEM
FUEL SYSTEM
DESCRIPTION
FUEL FILTER
(HIGH PRESSURE SIDE) . TANK
FUEL PUMP
PRESSURE SIDE)
OWOFX-12
This system supplies the necessary fuel for combustion at a constant pressure to the fuel injectors. Fuel is
metered and injected into the engine intake ports according to injection control signals from the engine con-
trol unit. The system consists of the fuel tank, the fuel pump, the fuel filters, the delivery pipe, the pressure
regulator, the fuel injectors, and the circuit opening relay. ._*
F-l 20