EC-760
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Diagnosis DescriptionINFOID:0000000001161752
INTRODUCTION
The ECM has an on board diagnostic system, which detects malfunctions related to engine sensors or actua-
tors. The ECM also records various emission-related diagnostic information including:
The above information can be checked using procedures listed in the table below.
×: Applicable —: Not applicable
*: When DTC and 1st trip DTC simultaneously appear on the display, they cannot be clearly distinguished from each other.
The malfunction indicator (MI) on the instrument panel lights up when the same malfunction is detected in two
consecutive trips (Two trip detection logic), or when the ECM enters fail-safe mode. (Refer to EC-1017,
"FailSafe".)
TWO TRIP DETECTION LOGIC
When a malfunction is detected for the first time, 1st trip DTC and 1st trip Freeze Frame data are stored in the
ECM memory. The MI will not light up at this stage. <1st trip>
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in
the ECM memory, and the MI lights up. The MI lights up at the same time when the DTC is stored. <2nd trip>
The “trip” in the “Two Trip Detection Logic” means a driving mode in which self-diagnosis is performed during
vehicle operation. Specific on board diagnostic items will cause the ECM to light up or blink the MI, and store
DTC and Freeze Frame data, even in the 1st trip, as shown below.
×: Applicable —: Not applicable
DTC AND FREEZE FRAME DATA
DTC and 1st Trip DTC
Emission-related diagnostic information Diagnostic service
Diagnostic Trouble Code (DTC) Service $03 of ISO 15031-5
Freeze Frame data Service $02 of ISO 15031-5
System Readiness Test (SRT) code Service $01 of ISO 15031-5
1st Trip Diagnostic Trouble Code (1st Trip DTC) Service $07 of ISO 15031-5
1st Trip Freeze Frame data
Test values and Test limits Service $06 of ISO 15031-5
Calibration ID Service $09 of ISO 15031-5
DTC 1st trip DTCFreeze Frame
data1st trip Freeze
Frame dataSRT code Test value
CONSULT-III×× × × ×—
GST×× ×—××
ECM××*— — ——
ItemsMI DTC 1st trip DTC
1st trip 2nd trip
1st trip
displaying2nd trip
displaying1st trip
displaying2nd trip
display-
ing BlinkingLighting
upBlinkingLighting
up
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0304 is
being detected×———— —×—
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0304 is
being detected——×——×——
One trip detection diagnoses (Re-
fer to EC-1020, "
DTCIndex".)—×——×———
Except above — — —×—××—
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-761
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The 1st trip DTC (whose number is the same as the DTC number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously, and the 1st trip DTC did not reoccur, the 1st trip
DTC will not be displayed.
If a malfunction is detected during the 1st trip, the 1st trip DTC is stored in the ECM memory. The MI will not
light up (two trip detection logic). If the same malfunction is not detected in the 2nd trip (meeting the required
driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same malfunction is detected in the
2nd trip, both the 1st trip DTC and DTC are stored in the ECM memory and the MI lights up. In other words,
the DTC is stored in the ECM memory and the MI lights up when the same malfunction occurs in two consec-
utive trips. If a 1st trip DTC is stored and a non-diagnostic operation is performed between the 1st and 2nd
trips, only the 1st trip DTC will continue to be stored. For malfunctions that blink or light up the MI during the
1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
Procedures for clearing the DTC and the 1st trip DTC from the ECM memory are described in “HOW TO
ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION”.
For malfunctions in which 1st trip DTCs are displayed, refer to “EMISSION-RELATED DIAGNOSTIC INFOR-
MATION ITEMS”. These items are required by legal regulations to continuously monitor the system/compo-
nent. In addition, the items monitored non-continuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of ISO 15031-5. 1st trip DTC detection occurs without lighting up the
MI and therefore does not warn the driver of a malfunction. However, 1st trip DTC detection will not prevent
the vehicle from being tested, for example during Inspection/Maintenance (I/M) tests.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in Work Flow procedure Step 2, refer to EC-685, "
Work Flow". Then perform DTC CONFIR-
MATION PROCEDURE or Component Function Check to try to duplicate the malfunction. If the malfunction is
duplicated, the item requires repair.
Freeze Frame Data and 1st Trip Freeze Frame Data
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engine speed, vehicle speed, absolute throttle position, base
fuel schedule and intake air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-III or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-III screen, not on the GST.
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MI on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
For example, the EGR malfunction (Priority: 2) was detected and the freeze frame data was stored in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st trip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or 1st
trip freeze frame data can be stored in the ECM). If freeze frame data is stored in the ECM memory and freeze
frame data with the same priority occurs later, the first (original) freeze frame data remains unchanged in the
ECM memory.
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM mem-
ory is erased. Procedures for clearing the ECM memory are described in “HOW TO ERASE EMISSION-
RELATED DIAGNOSTIC INFORMATION”.
How to Read DTC and 1st Trip DTC
With CONSULT-III
With GST
CONSULT-III or GST (Generic Scan Tool) Examples: P0340, P1148, P1706, etc.
These DTCs are prescribed by ISO 15031-5.
Priority Items
1Freeze frame data Misfire — DTC: P0300 - P0304
Fuel Injection System Function — DTC: P0171, P0172
2 Except the above items
3 1st trip freeze frame data
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-765
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WITH CONSULT-III
Selecting “SRT STATUS” in “DTC CONFIRMATION” mode with CONSULT-III.
For items whose SRT codes are set, a “CMPLT” is displayed on the CONSULT-III screen; for items whose
SRT codes are not set, “INCMP” is displayed.
WITH GST
Selecting Service $01 with GST (Generic Scan Tool)
MALFUNCTION INDICATOR (MI)
Description
The MI is located on the instrument panel.
1. The MI will light up when the ignition switch is turned ON without
the engine running. This is a bulb check.
If the MI does not light up, check MI circuit. Refer to MWI-15,
"WARNING LAMPS/INDICATOR LAMPS : System Diagram".
2. When the engine is started, the MI should go off.
If the MI remains on, the on board diagnostic system has
detected an engine system malfunction.
On Board Diagnostic System Function
The on board diagnostic system has the following four functions.
Diagnostic Test Mode I — Bulb Check
SAT652J
Diagnostic Test
ModeKEY and ENG.
Sta tusFunction Explanation of Function
Mode I Ignition switch in
ON position
Engine stoppedBULB CHECK This function checks the MI bulb for damage (blown, open
circuit, etc.).
If the MI does not come on, check MI circuit.
Engine running MALFUNCTION
WARNINGThis is a usual driving condition. When a malfunction is de-
tected twice in two consecutive driving cycles (two trip de-
tection logic), the MI will light up to inform the driver that a
malfunction has been detected.
The following malfunctions will light up or blink the MI in the
1st trip.
Misfire (Possible three way catalyst damage)
One trip detection diagnoses
Mode II Ignition switch in
ON position
Engine stoppedSELF-DIAGNOSTIC
RESULTSThis function allows DTCs and 1st trip DTCs to be read.
Engine running HEATED OXYGEN SENSOR 1
MONITORThis function allows the fuel mixture condition (lean or rich),
monitored by heated oxygen sensor 1, to be read.
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-769
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Explanation for Driving Patterns for “Misfire
Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
*1: When the same malfunction is de-
tected in two consecutive trips, MI will
light up.*2: MI will go off after vehicle is driven 3
times (pattern B) without any mal-
functions.*3: When the same malfunction is de-
tected in two consecutive trips, the
DTC and the freeze frame data will be
stored in ECM.
*4: The DTC and the freeze frame data
will not be displayed any longer after
vehicle is driven 80 times (pattern C)
without the same malfunction. (The
DTC and the freeze frame data still
remain in ECM.)*5: When a malfunction is detected for
the first time, the 1st trip DTC and the
1st trip freeze frame data will be
stored in ECM.*6: The 1st trip DTC and the 1st trip
freeze frame data will be cleared at
the moment OK is detected.
*7: When the same malfunction is de-
tected in the 2nd trip, the 1st trip
freeze frame data will be cleared.*8: 1st trip DTC will be cleared when ve-
hicle is driven once (pattern C) with-
out the same malfunction after DTC
is stored in ECM.
SEF392SA
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-771
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*1: When the same malfunction is de-
tected in two consecutive trips, MI will
light up.*2: MI will go off after vehicle is driven 3
times (pattern B) without any mal-
functions.*3: When the same malfunction is de-
tected in two consecutive trips, the
DTC and the freeze frame data will be
stored in ECM.
PBIB2551E
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-778
< FUNCTION DIAGNOSIS >[MR18DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to EC-760, "Diagnosis Description".
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
DTC WORK SUPPORT Mode
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJECTION Engine: Return to the original
trouble condition
Change the amount of fuel injec-
tion using CONSULT-III.If trouble symptom disappears, see
CHECK ITEM. Harness and connectors
Fuel injector
Heated oxygen sensor 1
IGNITION TIMING Engine: Return to the original
trouble condition
Timing light: Set
Retard the ignition timing using
CONSULT-III.If trouble symptom disappears, see
CHECK ITEM. Perform Idle Air Volume Learning.
POWER BALANCE Engine: After warming up, idle
the engine.
A/C switch OFF
Shift lever:Neutral
Cut off each fuel injector signal
one at a time using CONSULT-
III.Engine runs rough or dies. Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
COOLING FAN* Ignition switch: ON
Turn the cooling fan “LOW”, “HI”
and “OFF” CONSULT-III.Cooling fan moves and stops. Harness and connectors
IPDM E/R (Cooling fan relay)
Cooling fan motor
ENG COOLANT
TEMP Engine: Return to the original
trouble condition
Change the engine coolant tem-
perature using CONSULT-III.If trouble symptom disappears, see
CHECK ITEM. Harness and connectors
Engine coolant temperature sen-
sor
Fuel injector
FUEL PUMP RELAY Ignition switch: ON (Engine
stopped)
Turn the fuel pump relay “ON”
and “OFF” using CONSULT-III
and listen to operating sound.Fuel pump relay makes the operat-
ing sound. Harness and connectors
Fuel pump relay
PURG VOL CONT/V Engine: After warming up, run
engine at 1,500 rpm.
Change the EVAP canister
purge volume control solenoid
valve opening percent using
CONSULT-III.Engine speed changes according
to the opening percent. Harness and connectors
Solenoid valve
V/T ASSIGN ANGLE Engine: Return to the original
trouble condition
Change intake valve timing us-
ing CONSULT-III.If trouble symptom disappears, see
CHECK ITEM. Harness and connectors
Intake valve timing control sole-
noid valve
Test mode Test item Condition Reference page
HO2S1HO2S1 (B1) P0133
Refer to corresponding
trouble diagnosis for DTC.EC-817
HO2S1 (B1) P0134EC-823
HO2S1 (B1) P1143EC-823
HO2S1 (B1) P1144EC-901
HO2S2HO2S2 (B1) P0139EC-835HO2S2 (B1) P1146EC-906
HO2S2 (B1) P1147EC-912
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-781
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COMPONENT DIAGNOSIS
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DescriptionINFOID:0000000001161755
The specification (SP) value indicates the tolerance of the value that is displayed in “SPEC” of “DATA MONI-
TOR” mode of CONSULT-III during normal operation of the Engine Control System. When the value in “SPEC”
of “DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When the
value in “SPEC” of “DATA MONITOR” mode is NOT within the SP value, the Engine Control System may have
one or more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the
MI.
The SP value will be displayed for the following three items:
B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board correc-
tion)
A/F ALPHA-B1 (The mean value of air-fuel ratio feedback correction factor per cycle)
MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Component Function CheckINFOID:0000000001161756
1.START
Make sure that all of the following conditions are satisfied.
Vehicle driven distance: More than 5,000 km (3,107 miles)
Barometric pressure: 98.3 - 104.3 kPa (0.983 - 1.043 bar, 1.003 - 1.064 kg/cm
2, 14.25 - 15.12 psi)
Atmospheric temperature: 20 - 30°C (68 - 86°F)
Engine coolant temperature: 75 - 95°C (167 - 203°F)
Transmission: Warmed-up
- After the engine is warmed up to normal operating temperature, drive vehicle for 5 minutes.
Electrical load: Not applied*
Engine speed: Idle
*: Rear window defogger switch, air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
>> GO TO 2.
2.PERFORM “SPEC” OF “DATA MONITOR” MODE
With CONSULT-III
NOTE:
Perform “SPEC” in “DATA MONITOR” mode in maximum scale display.
1. Perform EC-689, "
BASIC INSPECTION : Special Repair Requirement".
2. Select “B/FUEL SCHDL”, “A/F ALPHA-B1” and “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode
with CONSULT-III.
3. Make sure that monitor items are within the SP value.
Is the inspection result normal?
YES >> END
NO >> Go to EC-782, "
Diagnosis Procedure".