ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-773
< FUNCTION DIAGNOSIS >[MR18DE]
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System readiness test (SRT) codes
Test values
ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
WORK
SUPPORTSELF-DIAGNOSTIC
RESULTS
DATA
MONI-
TORACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*
1FREEZE
FRAME
DATA*
2
SRT STA-
TUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS)×××
Camshaft position sensor (PHASE)×××
Mass air flow sensor××
Engine coolant temperature sensor××××
Heated oxygen sensor 1××××
Heated oxygen sensor 2××××
Wheel sensor×××
Accelerator pedal position sensor××
Throttle position sensor××
Intake air temperature sensor×××
Knock sensor×
EPS control unit×
Refrigerant pressure sensor×
Closed throttle position switch (accel-
erator pedal position sensor signal)×
Air conditioner switch×
Park/neutral position (PNP) switch××
Stop lamp switch××
Battery voltage×
Load signal×
ASCD steering switch××
ASCD break switch××
ASCD cluch switch××
ENGINE CONTROL COMPONENT PARTS
OUTPUT
Fuel injector××
Power transistor (Ignition timing)××
Throttle control motor relay××
Throttle control motor×
EVAP canister purge volume control
solenoid valve××××
Air conditioner relay×
Fuel pump relay×××
Cooling fan relay×××
Heated oxygen sensor 1 heater×××
Heated oxygen sensor 2 heater×××
Intake valve timing control solenoid
valve×××
Calculated load value××
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-775
< FUNCTION DIAGNOSIS >[MR18DE]
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*: The items are the same as those of 1st trip freeze frame data.
DATA MONITOR MODE
Monitored Item
×: Applicable
Monitored item Unit Description Remarks
ENG SPEED rpm Indicates the engine speed computed from the
signal of the crankshaft position sensor (POS)
and camshaft position sensor (PHASE). Accuracy becomes poor if engine
speed drops below the idle rpm.
If the signal is interrupted while the
engine is running, an abnormal value
may be indicated.
MAS A/F SE-B1 V The signal voltage of the mass air flow sensor is
displayed. When the engine is stopped, a certain
value is indicated.
When engine is running specification
range is indicated in “SPEC”.
B/FUEL SCHDL msec “Base fuel schedule” indicates the fuel injection
pulse width programmed into ECM, prior to any
learned on board correction. When engine is running specification
range is indicated in “SPEC”.
A/F ALPHA-B1 % The mean value of the air-fuel ratio feedback cor-
rection factor per cycle is indicated. When the engine is stopped, a certain
value is indicated.
When engine is running specification
range is indicated in “SPEC”.
This data also includes the data for
the air-fuel ratio learning control.
COOLAN TEMP/S°C or °F The engine coolant temperature (determined by
the signal voltage of the engine coolant tempera-
ture sensor) is displayed. When the engine coolant temperature
sensor is open or short-circuited,
ECM enters fail-safe mode. The en-
gine coolant temperature determined
by the ECM is displayed.
HO2S1 (B1) V The signal voltage of the heated oxygen sensor 1
is displayed.
HO2S2 (B1) V The signal voltage of the heated oxygen sensor 2
is displayed.
HO2S1 MNTR (B1) RICH/LEAN Display of heated oxygen sensor 1 signal during
air-fuel ratio feedback control:
RICH: means the mixture became “rich”, and
control is being affected toward a leaner mixture.
LEAN: means the mixture became “lean”, and
control is being affected toward a rich mixture. After turning ON the ignition switch,
“RICH” is displayed until air-fuel mix-
ture ratio feedback control begins.
When the air-fuel ratio feedback is
clamped, the value just before the
clamping is displayed continuously.
HO2S2 MNTR(B1) RICH/LEAN Display of heated oxygen sensor 2 signal:
RICH: means the amount of oxygen after three
way catalyst is relatively small.
LEAN: means the amount of oxygen after three
way catalyst is relatively large. When the engine is stopped, a certain
value is indicated.
VHCL SPEED SE km/h or mph The vehicle speed computed from the vehicle
speed signal sent from combination meter is dis-
played.
BATTERY VOLT V The power supply voltage of ECM is displayed.
ACCEL SEN 1
V The accelerator pedal position sensor signal volt-
age is displayed. ACCEL SEN 2 signal is converted by
ECM internally. Thus, it differs from
ECM terminal voltage signal. ACCEL SEN 2
MAIN SW ON/OFF Indicates [ON/OFF] condition from MAIN switch
signal.
CANCEL SW ON/OFF Indicates [ON/OFF] condition from CANCEL
switch signal.
THRTL SEN 1-B1
V The throttle position sensor signal voltage is dis-
played. THRTL SEN 2-B1 signal is converted
by ECM internally. Thus, it differs from
ECM terminal voltage signal. THRTL SEN 2-B1
EC-776
< FUNCTION DIAGNOSIS >[MR18DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
START SIGNAL ON/OFF Indicates start signal status [ON/OFF] computed
by the ECM according to the signals of engine
speed and battery voltage. After starting the engine, [OFF] is dis-
played regardless of the starter sig-
nal.
CLSD THL POS ON/OFF Indicates idle position [ON/OFF] computed by
ECM according to the accelerator pedal position
sensor signal.
RESUME/ACC SW ON/OFF Indicates [ON/OFF] condition from RESUME/AC-
CELERATE switch signal.
SET SW ON/OFF Indicates [ON/OFF] condition from SET/COAST
switch signal.
BRAKE SW1 ON/OFF Indicates [ON/OFF] condition from ASCD brake
switch signal or ASCD clutch switch signal.
BRAKE SW2 ON/OFF Indicates [ON/OFF] condition of stop lamp switch
signal.
VHCL SPD CUT NON/CUT Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the ASCD
set speed.
CUT: Vehicle speed decreased to excessively
low compared with the ASCD set speed, and
ASCD operation is cut off.
LO SPEED CUT NON/CUT Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the ASCD
set speed.
CUT: Vehicle speed decreased to excessively
low, and ASCD operation is cut off.
CRUISE LAMP ON/OFF Indicates [ON/OFF] condition of CRUISE lamp
determined by the ECM according to the input
signals.
SET LAMP ON/OFF Indicates [ON/OFF] condition of SET lamp deter-
mined by the ECM according to the input signals.
AIR COND SIG ON/OFF Indicates [ON/OFF] condition of the air condition-
er switch as determined by the air conditioner sig-
nal.
P/N POSI SW ON/OFF Indicates [ON/OFF] condition from the park/neu-
tral position (PNP) switch signal.
PW/ST SIGNAL ON/OFF [ON/OFF] condition of the power steering system
(determined by the signal sent from EPS control
unit) is indicated.
LOAD SIGNAL ON/OFF Indicates [ON/OFF] condition from the electrical
load signal.
ON: Rear window defogger switch is ON and/or
lighting switch is in 2nd position.
OFF: Both rear window defogger switch and light-
ing switch are OFF.
IGNITION SW ON/OFF Indicates [ON/OFF] condition from ignition switch
signal.
HEATER FAN SW ON/OFF Indicates [ON/OFF] condition from the heater fan
switch signal.
BRAKE SW ON/OFF Indicates [ON/OFF] condition from the stop lamp
switch signal.
INJ PULSE-B1 msec Indicates the actual fuel injection pulse width
compensated by ECM according to the input sig-
nals. When the engine is stopped, a certain
computed value is indicated.
CAL/LD VALUE % “Calculated load value” in the current airflow di-
vided by peak airflow. Monitored item Unit Description Remarks
EC-844
< COMPONENT DIAGNOSIS >[MR18DE]
P0171 FUEL INJECTION SYSTEM FUNCTION
P0171 FUEL INJECTION SYSTEM FUNCTION
DTC LogicINFOID:0000000001161814
DTC DETECTION LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MI (2 trip detection logic).
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Clear the mixture ratio self-learning value. Refer to EC-696, "
MIXTURE RATIO SELF-LEARNING VALUE
CLEAR : Special Repair Requirement".
2. Start engine.
Is it difficult to start engine?
YES >> GO TO 3.
NO >> GO TO 4.
3.RESTART ENGINE
If it is difficult to start engine, the fuel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
Does engine start?
YES >> Go to EC-845, "Diagnosis Procedure".
NO >> Check exhaust and intake air leak visually.
4.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Start engine and let it idle for at least 10 minutes.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-845, "Diagnosis Procedure".
NO >> GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-III
1. Turn ignition switch OFF and wait at least 10 seconds.
Sensor Input signal to ECM ECM function Actuator
Heated oxygen sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection control Fuel injector
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0171Fuel injection system too
lean Fuel injection system does not operate properly.
The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.) Intake air leaks
Heated oxygen sensor 1
Fuel injector
Exhaust gas leaks
Incorrect fuel pressure
Lack of fuel
Mass air flow sensor
Incorrect PCV hose connection
EC-848
< COMPONENT DIAGNOSIS >[MR18DE]
P0172 FUEL INJECTION SYSTEM FUNCTION
P0172 FUEL INJECTION SYSTEM FUNCTION
DTC LogicINFOID:0000000001161816
DTC DETECTION LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MI (2 trip detection logic).
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Clear the mixture ratio self-learning value. Refer to EC-696, "
MIXTURE RATIO SELF-LEARNING VALUE
CLEAR : Special Repair Requirement".
2. Start engine.
Is it difficult to start engine?
YES >> GO TO 3.
NO >> GO TO 4.
3.RESTART ENGINE
If it is difficult to start engine, the fuel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
Does engine start?
YES >> Go to EC-849, "Diagnosis Procedure".
NO >> Remove spark plugs and check for fouling, etc.
4.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Start engine and let it idle for at least 10 minutes.
Is 1st trip DTC detected?
YES >> Go to EC-849, "Diagnosis Procedure".
NO >> GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-III
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for 10 min-
utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
Sensor Input signal to ECM ECM function Actuator
Heated oxygen sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection control Fuel injector
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0172Fuel injection system too
rich Fuel injection system does not operate properly.
The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.) Heated oxygen sensor 1
Fuel injector
Exhaust gas leaks
Incorrect fuel pressure
Mass air flow sensor
ECM
EC-1019
< ECU DIAGNOSIS >[MR18DE]
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DTC Inspection Priority ChartINFOID:0000000001161993
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
P1124
P1126Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1128 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1229 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1805 Brake switch ECM controls the electric throttle control actuator by regulating the throttle opening to a
small range.
Therefore, acceleration will be poor.
Vehicle condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
P2122
P2123
P2127
P2128
P2138Accelerator pedal position
sensorThe ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor. DTC No. Detected items Engine operating condition in fail-safe mode
Priority Detected items (DTC)
1 U1000 U1001 CAN communication line
U1010 CAN communication
P0102 P0103 Mass air flow sensor
P0112 P0113 P0127 Intake air temperature sensor
P0117 P0118 P0125 Engine coolant temperature sensor
P0122 P0123 P0222 P0223 P1225 P1226 P2135 Throttle position sensor
P0327 P0328 Knock sensor
P0335 Crankshaft position sensor (POS)
P0340 Camshaft position sensor (PHASE)
P0500 Vehicle speed sensor
P0605 ECM
P1229 sensor power supply
P1610 P1611 P1614 NATS
P1706 Park/Neutral position (PNP) switch
P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor
2 P0132 P0133 P0134 P1143 P1144 Heated oxygen
P0135 Heated oxygen sensor 1 heater
P0138 P0139 P1146 P1147 Heated oxygen sensor 2
P0141 Heated oxygen sensor 2 heater
P0444 EVAP canister purge volume control solenoid valve
P 1111 I n t a k e v a l v e t i m i n g c o n t r o l s o l e n o i d v a l v e
P1122 Electric throttle control function
P1124 P1126 Throttle control motor relay
P1128 Throttle control motor
P1217 Engine over temperature (OVERHEAT)
P1805 Brake switch
3 P0011 Intake valve timing control
P0171 P0172 Fuel injection system function
P0300 - P0304 Misfire
P0420 Three way catalyst function
P1121 Electric throttle motor actuator
P1211 TCS control unit
P1212 TCS communication line
P1564 ASCD steering switch
P1572 ASCD brake switch
P1574 ASCD vehicle speed sensor
EC-1024
< SYMPTOM DIAGNOSIS >[MR18DE]
ENGINE CONTROL SYSTEM
SYMPTOM DIAGNOSIS
ENGINE CONTROL SYSTEM
Symptom TableINFOID:0000000001161997
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 11232 22 3 2EC-978
Fuel pressure regulator system 334444444 4EC-1035
Fuel injector circuit 11232 22 2EC-975
Evaporative emission system 334444444 4EC-745
Air Positive crankcase ventilation sys-
tem
334444444 41EC-987
Incorrect idle speed adjustment 1 1 1 1 1EC-692
Electric throttle control actuator 112332222 2 2EC-885,
EC-887
IgnitionIncorrect ignition timing adjustment33111 11 1EC-693
Ignition circuit 11222 22 2EC-981
Main power supply and ground circuit 22333 33 23EC-789
Mass air flow sensor circuit
1
122
222 2EC-799
Engine coolant temperature sensor circuit
333EC-807
Heated oxygen sensor 1 circuitEC-813
,
EC-817
,
EC-823
,
EC-896
,
EC-901
Throttle position sensor circuit
22EC-810
,
EC-852
,
EC-924
,
EC-926
,
EC-956
Accelerator pedal position sensor circuit 3 2 1EC-948
,
EC-952
,
EC-956
Knock sensor circuit 2 3EC-860
Crankshaft position sensor (POS) circuit 2 2EC-862
EC-1032
< PRECAUTION >[MR18DE]
PRECAUTIONS
When measuring ECM signals with a circuit tester, never allow
the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
Do not use ECM ground terminals when measuring input/out-
put voltage. Doing so may result in damage to the ECM’s tran-
sistor. Use a ground other than ECM terminals, such as the
ground.
Do not operate fuel pump when there is no fuel in lines.
Tighten fuel hose clamps to the specified torque.
Do not depress accelerator pedal when starting.
Immediately after starting, do not rev up engine unnecessar-
ily.
Do not rev up engine just prior to shutdown.
When installing C.B. ham radio or a mobile phone, be sure to
observe the following as it may adversely affect electronic
control systems depending on installation location.
-Keep the antenna as far as possible from the electronic con-
trol units.
-Keep the antenna feeder line more than 20 cm (8 in) away
from the harness of electronic controls.
Do not let them run parallel for a long distance.
-Adjust the antenna and feeder line so that the standing-wave
ratio can be kept smaller.
-Be sure to ground the radio to vehicle body.
SEF348N
SEF709Y
SEF708Y