F 149 MAZDA PROTEGE 1992 Service Manual

TROUBLESHOOTING GUIDE F
26 POOR FUEL ECONOMY
DESCRIP-
l Fuel economy unsatisfactory TION
[TROUBLESHOOTING HINTS]
While fuel consumption is drastically increased by city driving, short-run operation, stop and go driving, extended winter
warm-up periods, etc., as opposed to “trip” mileage, an attempt should be made to determine these factors when con-
fronted with “poor mileage” conditions. However, since the operator is not always at fault, the following is offered.
@II Operator depressing accelerator more than usual due to
@ Air/Fuel mixture too rich
low engine power
l Poor ignition *High fuel line pressure
@ Alcohol blended fuel used
*Low intake air amount
l Electronic spark advance control system malfunction @ High vehicle load l Low tire pressure
*Clutch slipping/ATX slipping l Incorrect tire size l Exhaust component restricted l Brake dragging ;TEP
INSPECTION ACTION
1
Check factors other than engine Yes
Go to next step
l Low tire pressure = Section Q 9 Unrecommended tire srze v Section Q l Clutch slipping w Section H l Brake dragging No
0 Section P Repair
l Exhaust component restricted cz= page F-136
2
Check if air hoses are connected correctly - Yes
Go to next step CI page F-109
No
Repair 3
Check if “00” IS displayed on Self-Diagnosis
Yes
Checker with ignition switch ON Go to next step W page F-82 No
SYSTEM SELECT: 1 Service Code No. displayed Check for cause (Refer to specified
check sequence) w page F-63
“88” flashes
Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
* If OK, replace ECU CT= page F-149 e If not OK, check wiring between
ECU and Self-Diagnosis Checker 4
Check for correct intake manifold vacuum at idle
Yes Go to next step Vacuum: More than 450 mmHg (17.7 inHg) No
Check for air leakage at intake air sys-
tem components 5
Check if air cleaner element is clean Yes
Go to next step CT= page F-79
No
Replace air cleaner element
F-75

TROUBLESHOOTING GUIDE
27 MIL ALWAYS ON
DESCRIP- *Self-Diagnosis Checker does not indicate Malfunction Code No. but MIL always ON
TION
[TROUBLESHOOTING HINTS]
*Short circuit in wiring harness
l ECU malfunction
iTEF 1
1
-
s
Disconnect (Y/B) wire from ECU and check if
MIL goes off
‘YIB
ATX YIB
INSPECTION ACTION
Yes Replace ECU CT page F-149
No Check for short circuit in wiring be-
tween instrument cluster and ECU
23UOFX-042
28
MIL NEVER ON
IESCRIP- *Self-Diagnosis Checker indicates Malfunction Code No. of input device but MIL never ON
RON *Other indicator and warning lamps OK
:TROUBLESHOOTING HINTS]
b Bulb burned
‘Open circuit in wiring harness
m ECU malfunction
TEP INSPECTION
ACTION
1 Ground (Y/B) wire at ECU with jumper wire and
Yes Check connection of ECU connector
check if MIL comes on
MTX e If OK, replace ECU w page F-149
I- i -!~ !r--~r’:~;-‘;- --~_:- ,
1 i r 1 1 1 ;-.:,~;~$~& {-;&# ,$&]j 4 If not OK, repair ECU connector
! No
Check if bulb is OK
ATX 13 If OK, repair (Y/B) wire between
ECU and instrument cluster
e If not OK, replace bulb CT page T-83
23UOFX-043
29 A/C DOES NOT WORK
DESCRIP- *Blower fan operates but magnet clutch does not operate
TION
[TROUBLESHOOTING HINTS]
*Open or short circuit in wiring harness
*A/C relay, A/C switch, or magnetic clutch malfunction
l ECU malfunction
TEP/ INSPECTION ACTION
1 1 Check ECU
terminal 10 (MTX) 10 (ATX) voltage 1
Yes Check ECU terminal 1 J (MTX) 1 L (ATX)
OK
CT= page F-152
MTX
T7J++!;i”-
L
ATX
No voltage OK
CT page F-152
1-3 If OK, check A/C system
c3- page U-30
~3 If not OK, replace ECU CT page F-149
Check for cause w page F-153
F-77

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

F SELF-DIAGNOSIS FUNCTION
r C :ODE No.
03 (DISTRIBUTOR G-SIGNAL) - DOHC ¶
El
i- I
INSPECTION
Check distributor circuit for poor connection ACTION
Yes Repair or replace connector
1
2
-s-
-T-
--c
--if-
7
-ii- No
I I Go to next step
Check if Code No.02 is also present Yes
I I Go to next step
Check terminal-wire for continuity No Go to Step 5
Yes Go to next step
Check if battery voltage exists at distributor
terminal-wire No Repair of replace
Yes Go to next step
No
I I
Check for open circuit in wiring from
distributor to main relay
Check terminal-wire between distributor and
Yes Go to next step
ECU terminal 2G (MTX) 2J (ATX) for continuity
and ground
No Repair or replace
Ct$; if$CU terminal 2G (MTX) 2J (ATX) volt- Yes Replace ECU r=+ page
F-149 CT page
F-154 No
Go to next step
Check if OV or 4.5V--53 exists at distributor Yes
I I Replace distributor
terminal-wire
No
I I Go to next step
I Check if 4.5V--5.5V exists at ECU terminal 2G
(MTX) 2J (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 I 23UOFX-0: i5
F-88

SELF-DIAGNOSIS FUNCTION
:ODE No. 08 (AIRFLOW METER)
TEP INSPECTION ACTION
1 Check airflow meter circuit for poor connection Yes Repair or replace connector
No Go to next step
2 Check if Code No.10 is also present Yes Check for open circuit in wiring from
airflow meter terminal-wire (BILG) to
ground
Go to next step
3 Check if resistance of airflow meter is OK
4 Check wire harness between airflow meter and
Repair or replace wire harness
5 Check if ECU terminals voltages are OK Yes Replace ECU CT= page
F-149
MTX...2D, 2K and 20
ATX... 2B, 21 and 3D a page
F-152 No Check for short circuit in wiring from
airflow meter to ECU
23UOFX-058 .-
.- ,
F-90

SELF-DIAGNOSIS FUNCTION
:ODE No. 09 (WATER THERMOSENSOR)
iTEP INSPECTION ACTION
1 Check water thermosensor circuit for poor con-
Yes Repair or replace connector
nection
3 Check if resistance of water thermosensor is OK Yes Go to next step
Coolant temp. Resistance (kg)
No Replace water thermosensor
-20% ( -4OF) 14.6-17.8
2o”c ( 68OF) 2.21-2.69
80% (176OF) 0.29-0.35
4 Check if same Code No. is present following Yes Go to next step
after-repair procedure
w page F-104 No
Water thermosensor and circuit OK
5 Check if ECU terminals voltages are OK
Yes Replace ECU w page F-149
MTX...2D and 20
ATX...2E and 3D
w page F-152 No Check for short circuit in wiring from
water thermosensor to ECU
-- ._-..__
23Uu~X-ut
4
-’
F-92

F SELF-DIAGNOSIS FUNCTION
:ODE No.
10 (INTAKE AIR THERMOSENSOR - IN AIRFLOW METER)
TEP INSPECTION
ACTION
1 Check intake air thermosensor circuit for poor
Yes Repair or replace connector
connection
No Go to next step
2 Check if Code No.08 is also present
Yes Check for open circuit in wiring from
airflow meter terminal wires (BILG) and
(B/BR) to ground
Go to next step
3 Check wire harness between intake air
thermosensor and ECU for continuity
4 Check if resistance of airflow meter between
Yes Go to next step
terminals C (BIBR) and G (R/B) is OK
r
Temperature ~ No
Resistance (kg) Replace airflow meter
-20% 13.6-18.4
20% 2.21-2.69
60% 0.493-0.667
5 Check if same Code No. is present following
Yes Go to next step
after-repair procedure
CT page F-104 No
Intake air thermosensor and circuit OK
6 Check if ECU terminals voltages are OK Yes Replace ECU IT- page F-149
MTX...2D and 2P
ATX... 2K and 3D
CT page F-152 No Check for short circuit in wiring from
intake air thermosensor to ECU
23UOFX-06 -
F-94

F SELF-DIAGNOSIS FUNCTION
:ODE No. 12 (THROTTLE SENSOR - ATX)
iTEP INSPECTION ACTION
1 Check throttle sensor circuit for poor connection Yes Repair or replace connector
No Go to next step
2 Check wire harness between throttle sensor and Yes Go to next step
ECU for continuity
Throttle sensor ECU - No Repair or replace
A (LG/R) 2K (MTX) 21 (ATX)
B U-4 2M (MTX) 2F (ATX)
D (BIBR)
20 (MTX) 3D (ATX)
3 Check if resistances between terminals B (LGIW)
Adjust or replace throttle sensor w page F-169
4
r.%$ if$CU terminal 2M (MTX) 2F (ATX) volt- Yes Replace ECU w page F-149
w page F-154 NO
Check for short circuit in wiring from
throttle sensor to ECU
23UOFX-06
.-’

F SELF-DIAGNOSIS FUNCTION
CODE No.
STEP
1
Repiace ECU -- -.. - 14 (ATMOSPHERIC PRESSURE SENSOR - IN ECU)
ACTION
m page F-149 -.
23UOFX-069
:ODE No. 15 (OXYGEN SENSOR - INACTIVATION)
Note
l If Code Nos. 15 and 17 are both present, first perform the checking procedure for Code No.17
iTEP
INSPECTION ACTION
1 Check oxygen sensor circuit for poor connection
YeSi Repair or replace connector
No Go to next step
2 Check if oxygen sensor output voltage is OK Yes
Go to next step
rr5+ page F-171
No Replace oxygen sensor
3 Check wire harness between oxygen sensor and Yes Go to next step
ECU terminal 2N (MTX) 2C (ATX) for continuity
NO Repair or replace
4 Check if ECU terminal 2N (MTX) 2C (ATX) volt-
Yes Go to next step
age is OK
w page F-154
No
Check for short circuit in wiring from
oxygen sensor to ECU
5 Check if sensitivity of oxygen sensor is OK
Yes Replace ECU
w page F-149
CT page F-171
No Try known good oxygen sensor and
check if condition improves w page F-172
23UOFX-07C
F-98

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'