ECU MAZDA 323 1992 Suplement User Guide

SELF-DIAGNOSIS FUNCTION F3 I
Open or short crcuit
13EOFS322
Caution l If there is more than one failure present, the code numbers will be indicated in numerical or-
der, lowest number first.
l After repairing a failure, turn off the ignition switch, disconnect the negative battery cable,
and depress the brake pedal for at least twenty seconds to erase the service code from the
ECU memory. II
F3-17

F3 SELF-DIAGNOSIS FUNCTION
:ODE NO. 25 {SOLENOlD VALVE - PRESSURE REGULATOR CONTROL) (Low temperature opoeration)
INSPECTION ACTION
Disconnect connector from ECU; IS there battery Yes Check ECU termrnal connector for poor
voltage at ECU terminal 2T (G/C) wrth Ignition connection
switch ON?
4 If OK, replace ECU
CT page F3-2
c3 If not OK, repatr or replace connector
NO Go to next step
2 In same condition as rn Step 1. is there battery Yes Repair or replace wlrrng harness (G/O)
voltage at sofenord vatve (PRC low temp.) con-
nector termrnal wrre (G/O)?
NO Go to next step
3 Is solenord valve (PRC low temp ) UK7 Yes Check for a short or open crrcuit in WII-
CT page F343 ing harness (main relay [FUEL INJ re-
lay] - solenoid valve [PRC low temp.])
NO Replace solenord valve (PRC tow temp.)
1
t3EOF3-323
CODE NO. 35 (SOLENOID VALVE - PRESSURE REGULATOR CONTROL) (High temperature opoeration)
STEP lNSPECTlON ACTlON
1 Disconnect connector from ECU: is there battery Yes Check ECU terminal connector for poor
voltage a? ECU terminal 22 (G) with rgnttlon connection
swttch ON7
4 If OK, replace ECU
J page F3-2
e If not OK, repair or replace connector
No Go to next step
2 In same condrtron as In Step 1, is there battery Yes
voltage at solenoid valve (PRC high temp.) con- Repair or replace wiring harness (G)
nector terminal wire (G)?
No Go to next step
3 Is solenoid valve (PRC high temp ) OK7 Yes Check for a short or open circuit In wir-
r;r page F343 ing harness (marn relay [FUEL INJ re-
WI - sofenord valve [PRC high temp.])
No Replace solenoid valve
(PRC high temp.)
f3EOF3-324
Circuit Diagram
ECU
I
2T 22 I
G
TO MAIN RELAY
I SOLENOID
VALVE
(PRC HIGH TEMP.)
F3-18 :3EOf3 32 5
--
TRW
RELAT
c
-..


INPUT
--
KNOCH
--
DIAGM
(TEN T
--
IGNITIi
(STAR1
--
E/L SIC
-a
P/S PR
--
A/c SYI
--
NEUTR
SWITCI
--
STUPb
--
ATMDI
SENSQ
-a
THRUI
-..
INfAk.1
--
AlFlFLC
--
UXYGE
--
WATEF
--
DlSfRl

F3 TROUBLESHUOTING GUIDE
TROU8LESHOOTlNG GUIDE
RELATIONSHIP CHART
.

OUTPUT DEVICE
INPUT DEVICE

w
3
s
s
KNOCK SENSOR
0
0 0 0 DtAGNOStS CONNECTOR
(TEN TERMINAL)
0 0 0 IGNITION SWlTCH
(START POSITION) 0 0
0
0
0 0
0 0
0 0
0
0
0
0
0 0 0 0
E/L SIGNAL* 0
P/S PRESSURE SWITCH 0
0
A/C SWtTCH
NEUTRAL AND CLUTCH
SWITCHES
STOPLIGHT SWITCH
ATMOSPHERIC PRESSURE
SENSOR (IN ECU)
THROTTLE SENSOR
0 0 0 0
0
0
0 0’
0
0 0
0
0 0
0
’ 0
0
0 0 0 0 0 0 0
0 I
0 ~ INTAKE AIR THERMOSENSOR 0 0 0 0
0 -~
OXYGEN SENSOR
0 0 0 0 WATER THERMOSENSOR
A
0
* 0 0 0 c 0
13
3F3-32 IN, o . E/L SIGNAL: Blower fan control switch second position or higher, electric cooling fan operating, headlights
rear window defroster ON.
F3-19
i

TRUU8LESH00TlNG GUIDE F3
13EOF3-328
13EOF3-329
1
PRECAUTIONS
Fuel Pressure Release and Servicing Fuel System
Fuel
in the fuel system remains under high pressure when the engine is not running.
a) Before disconnecting any fuel line, release the fuel pres-
sure from the fuel system to reduce the possibility of injury
or fire as discribed below.
1. Start the engine.
2. Push the rear seat cushion buttons and remove the
cushion.
3. Disconnect the fuel pump connector.
4. After the engine stalls, turn off the ignition switch.
5. Reconnect the fuet pump connector and install the rear
seat cushion.
b) Use a rag as protection from fuel spray when disconnect-
ing the fuel hoses.
Plug the hoses after removal.
c) When inspecting the fuel system, use a suitable fuel pres-
sure gauge.
Caution
l install hose clamps to secure the fuet pressure
gauge to the fuei fitter and the fuel main hose to pre-
vent fuel leakage.
Pinching Hose
When pinching an air hose-or a fuel hose with pliers, wrap
the hose with a rag to prevent damage,
F3-2 t

F3 TROUBLESHOOTING GUIDE
SYMPTOM TROUSLESHOOTING
2 . CRANKS NORMALLY BUT WILL NOT START (NO COMBUSTION)
LIESCRIP-
l Engine cranks at normal speed but shows no sign of firing l Battery in normal condition
TION *Throttle valve not held fufly open while cranking (dechoke system not operating}
l Fuel in tank
UROOBLESHUOTlNG HINTS]
@ No spark
@.I low fuei tine pressure
l Ignition control malfunction @I Low engine compresslon l Ignition system component malfunction
@ No fuel injection
l Fuel pump inoperative l Ihjectors inoperative
;TEP
INSPECTION
I ACTION
1
Is strong btue spark visible at disconnected high- Yes Go to Step 3
tension lead?
NO Go to Step 2
2 Is “00” dlsplayed on Self-Dlagnosjs Checker
Yes
with ignltron switch ON? Check rgnltion system (Refer to
Troubleshooting “Misfire”)
c7 Section G
SYSTEM SELECT: 1 No
Service Code No. displayed Check for cause (Refer to specified
check sequence)
G- page
F3-16
“66” flashes
Check ECU termrnal 1F voltage
3 page W-45

Voltage: Battery vabage
(ignition switch ON)
W: SELF TEST C+ If OK, replace ECU
4 If not OK, check wiring
CT page F3-2
(ECU
- Self-Diagnosis Checker)
3
Connect diagnosis connector terminals F/P and
Yes
GND with jumper wire; IS fuel pump operating Does engine start in this condition?
sound heard wjth ignition switch ON?
4 If it does, check circuit-opening
relay
4 If it does not, go to Step 5
No Go to next step
F3-22
iTEF
6
8

__ _ 7 _-. _ , ._ _) .--.Kze - __ F3 TROU5l.ESHOOTING GUIDE
ZEP WSPECTION ACTION
9 Is engine compression correct? Yes Go to next step
e
c7 Section 82
NO Check engme condrtlon CT Section B2
Engine compression:
l Worn piston, piston rings or cylinder
1059 kPa 110.8 kgflcm2, 152 psi I-300 rpm wall
l Damaged cylr nder head gasket
*Damaged or warped cylinder head
l Improper valve seating
*Valve sticking in guide
10 Are all spark plugs OK? Yes Go to next step
c7 Section G
l Wear and carbon buildup l Plug gap l Damage No Clean, adjust
11 Try known good ECU; does condftlon rmprove’
CT page F3-2
_ -w^r- ^^<
F3-24 pc?t.
@ Air,1 l F..
et
l Irtj
TEP
2

F3 TROUBLESHOOTING GUIDE
I- STEP lNSPECTlON ACTION
Yes Go to Step 8
5 In same condition as in Step 2, IS fuel ilne pres-
sfire held after Igrxtbon swatch rs turned OFF?
Fuel line pressure: More than 147 kPa
Il.5 kgflcm’, 21 Psi 1 for 5 min.
6 In same condition as in Step 3, IS fuel line pres-
sure held after lgnltron switch IS turned OFF?
Fuel line pressure: More than 147 kPa
{ t.5 kgf/cm*, 21 psi) for 5 min.
No
I Go to next step
Plug both vcuum ports of pressure regulator; IS
fuel lme pressure held after ignltlon switch is
turned OFF? Yes Replace pressure regulator
r~ page F3-3
Fuel line pressure: More than 147 kPa
{ 1.5 kgf/crn*, 21 psi] for 5 min.
NO Check fuel pump hold pressure
e If OK, check InJector for fuel
leakage
e If not OK reptace fuel pump ZF- page F3-42
T page F3-3
8 Dlscofinect water thermosensor connector, does
engtne start? Yes Check water thermosensor
e ff OK. check connectrons of water
thermosensor and ECU 2Q terminal
Q If not OK, replace water thermo-
sensor
ET page F3-13
No 1 Go to next step --~
Is “00” drsplayea on Self-Diagnosis Checker
with ignition switch ON? 9 Yes Go to next step
NO Service Code No. displayed
Check for cause (Refer to specified
check sequence)
c7 page F3-16 SYSTEM SELECT, 1
“88” flashes
Check ECU terminal IF voltage
KIT page F3-45
Voltage: Battery voltage
(ignition switch ON)
e If OK, replace ECU
ET- page F3-2
e If not OK, check wiring
(ECU - Self-Diagnosis Checker)
Y %EtECT SW: A
Yes 1 Go to next step 10 Are rf ECU termrnaf voltages are OK?
(especjaffy 1C. 2D. and 2Q)
CT page F3-45
NO Check for cause
Yes Replace ECU
=T page F3-2
No Change to another brand of fuel
13EOF3 331 Try known good ECU, does condition improve?
CT page F3-2
F3-26

TROUBLESHOOTING GUlDE F3
7 CRANKS NORMALLY BUT HARD TO START - AFTER WARM-UP
*
l Engrne cranks at normal speed but requkres excessive cranking time before starting after running and being
DESCRIP- hot soaked
TION
l Battery rn normal condition l Engine starts normatly when cold
*Engine runs normally at Idle (If idle condrtron is not OK, refer to “Rough idle” ~Nos. 8-l 21)
[ ~ROUBLESHOOTLNG HINTS1
[ i 5 ArrlFuel mixture too Rich - l Fuel rqection control malfunction l lnpector fuet leakage
I
TEP tNSPECTlON @ Vaporlock
l Fuel pressure not held rn fuel line after engrne IS
stopped
l Pressure regulator control system malfunction
I ACTION
1 Is “00” dispiayed on Self-Diagnoses
Checker wrth rgnrtron switch ON7
SYSTEM?_SELECT. 1
SELECT SW. A
Remove vacuum hose from pressure regulator
(port A) ancI plug rt. dOt?S engine start normally’-,
Remove both vacuum hoses from pressure regu-
lator (ports A and Bj and plug them; does en-
gine start normally7
@
PtUG
/ /
Are ECU terminal voltages OK
(especially 1 C, 20, 20 and 2T)?
w page F3-46 Yes Go to next step
No Service Code No. displayed
Check for cause (Refer to specified
check sequence) CT oaae F3-16
“88” flashes
Check ECU terminal 1F voltage
Voltage: Battery voltage
(ignition switch ON) w page F3-45
( cs> It OK. replace ECU
/ w page F3-2’
3 If not OK, check wlrtng
(ECU - Self-Dlagnosrs ChecKer)
Yes Check pressure regulator control sys-
.
tern (high temperature operation) w page F3-43
I NO Go to next step
Check pressure regulator control sys-
tem (low temperature operation)
No 1 Go to next step
Yes Go to next step
NO Check for cause
F3-27

F3 TROU8LESliOOTING GUIDE
iTEP INSPECTION
ACTtUN
5 Run engine at idle; is fuel line pressure held af-
Yes Go to next step
ter ignition switch is turned OFF?
Fuet Ijne pressure: More than 147 kPa No Plug both vacuum potts of pressure
{1,5 kgflcd, 21 pdf for 5 min. regulator;
and check if fuel line pres-
sure is held after ignition switch is
turned OFF
NSTAtl CLAMPS 4 If it is, replace pressure regulator
c3 If it is not, check fuel pump hold CT page F3-3
pressure
If fuel pump is OK, check injectors
for fuet leakage
CT- page F3-4
6 Warm up engine to normal operating tempera-
Yes
ture and stop it Change to another brand of fuel
Connect diagnosis connector terminals F/P and
GND with jumper wire for 3 minutes with rgnitlon
switch ON; does engine start easily?
No Go to next step
7 Try known good ECU; does condition improve?
Yes Replace ECU
CT page F3-3 w- page F3-3
No Change to another brand of fuel
t3EOF3
F3-28

TROUBLESHOOTING GUIDE F3
8
1 ROUGH IDLE/ENGINE STALLS AT IDLE - ALWAYS
DESCRtP- 1 l Engine starts normally but stalls or vibrates excessively at idle in every condition
TION
[TROUBLESHOOTiNG HlNTSJ @ Air/Fuel mixture tw lean @ Incorrect idle-speed l ldiespeed misadjustment l Idle-speed control malfunction
$I One or more spark plugs not firing
9 Low engine compression
B Airflow meter stuck l Air leakage l Fuel injection control malfunction
*Low fuel line pressure
@ One or more injectors clogged or not
@ Low intake air amount operating
INSPECTION
Is “00” displayed on Self-Diagnosis
Checker with ignition switch ON?
1
SYSTEM SELECT: 1
ACTION
Go to next step
Service Code No. displayed Check for cause (Refer to specified
check sequence) c7 page F3-16
“88” flashes
Check ECU terminal IF voltage
(17 page F345
--.
‘\.
Voltage: Battery v&age
(Ignition switch ON)
4 If UK, replace ECU IT page F3-2 c3 If not OK, check wiring
(ECU - Self-Diagnosis Checker) Y -SELECT SW: A
Are ECU terminal voltages OK
(especially 20, 20, and ZQ)?
D page F3-45 Yes
Gu to next step
NO Check for cause
Disconnect each high-tens&on lead at idle: does
engine speed decrease equally at each cylindeR Yes Go to Step 9
NO Go to next step
Is injector operating sound heard at idle? [ Yes Go to Step 7
t- NO Stop engine and go to next step
Yes Check if injector resistance is OK
CT page F3-41 Is there battery voltage at each injector connec-
tor (No.1 (P), No.2 (R), No.3 QV), No.4 (0)) with
ignition switch ON?
Resktance: Approx. 2.110
(at 20*C [68*F))
4 if it is, check wiring
(ECU - Injector)
c3 If it is not, replace itijector
Go to next step
NO
Is there battery v&age at injector resistor (W/R)
I .Yes
with ignition switch ON? Check mjeotor resistor
4 tf OK, check for short circuit in wir-
ing (Injector resistor-Injector)
e3 If not OK,’ replace injector resistor
Check for open circuit in wiring (Main
relay (FUEL INJ relay)-Injector resistor)
Go to next step
t NO 1
Is strong blue soark visible at each disconnected Yes
‘Check ‘high-tension lead
4 If UK. check distributor cap and
rotor .
c3 If not OK, replace high-tension lead
‘-F3-29