
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
Engine Cylinder head
55555 55 5
EM section Cylinder head gasket 4 3
Cylinder block
66666 66 64 Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Valve
mecha-
nismTiming chain
55555 55 5 EMsection Camshaft
Intake valve
3
Exhaust valve
Exhaust Exhaust manifold/Tube/
Muffler/Gasket
55555 55 5 FEsection
Three way catalyst
Lubrica-
tionOil pan/Oil strainer/Oil
pump/Oil filter/Oil gallery
55555 55 5MA, EM and
LC sections
Oil level (Low)/Filthy oil
LC section Cooling Radiator/Hose/Radiator filler
cap
55555 55 45 Thermostat 5
Water pump
Water gallery
Cooling fan 5 EC-334
Coolant level (low)/
Contaminated coolantMA section
1 - 6: The numbers refer to the order of inspection.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONQG
Symptom Matrix Chart (Cont'd)
EC-127

DTC and MI Detection LogicNJEC0626When a malfunction is detected, the malfunction (DTC) is stored in the ECM memory.
The MI will light up each time the ECM detects malfunction. For diagnostic items causing the MI to light up,
refer to ªTROUBLE DIAGNOSIS Ð INDEXº, EC-492.
Diagnostic Trouble Code (DTC)NJEC0627HOW TO READ DTCNJEC0627S01The DTC can be read by the following methods.
Without CONSULT-II
ECM displays the DTC by a set of four digit numbers with MI illumination in the diagnostic test mode II (Self-
diagnostic results). Example: 0103, 0807, 1002, etc.
With CONSULT-II
CONSULT-II displays the DTC in ªSELF-DIAG RESULTSº mode. Examples: P0115, P0571, P1202, etc.
These DTCs are prescribed by ISO15031-6.
(CONSULT-II also displays the malfunctioning component or system.)
+Output of the trouble code means that the indicated circuit has a malfunction. However, in the Mode
II it does not indicate whether the malfunction is still occurring or occurred in the past and returned
to normal.
CONSULT-II can identify them. Therefore, using CONSULT-II (if available) is recommended.
HOW TO ERASE DTCNJEC0627S02How to Erase DTC (With CONSULT-II)NJEC0627S02011. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
5 seconds and then turn it ªONº (engine stopped) again.
2. Touch ªENGINEº.
3. Touch ªSELF-DIAG RESULTSº.
4. Touch ªERASEº. (The DTC in the ECM will be erased.)
SEF246Z
The emission related diagnostic information in the ECM can be erased by selecting ªERASEº in the ªSELF-
DIAG RESULTSº mode with CONSULT-II.
How to Erase DTC (Without CONSULT-II)NJEC0627S02021. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
5 seconds and then turn it ªONº (engine stopped) again.
2. Change the diagnostic test mode from Mode II to Mode I by using the data link connector. (See EC-524.)
The emission related diagnostic information in the ECM can be erased by changing the diagnostic test mode.
+If the battery is disconnected, the emission-related diagnostic information will be lost after approx.
24 hours.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD
DTC and MI Detection Logic
EC-522

DESCRIPTION FOR WORK FLOWNJEC0631S01
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using
the ªDIAGNOSTIC WORKSHEETº, EC-532.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II) the DTC, then erase the
DTC. Refer to EC-522.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-559.
Study the relationship between the cause, specified by DTC, and the symptom described by the customer. (The
ªSymptom Matrix Chartº will be useful. Refer to EC-541.) Also check related service bulletins for information.
STEP IIITry to confirm the symptom and under what conditions the incident occurs.
The ªDIAGNOSTIC WORK SHEETº is useful to verify the incident. Connect CONSULT-II to the vehicle in DATA
MONITOR (AUTO TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-559.
If the malfunction code is detected, skip STEP IV and perform STEP V.
STEP IVTry to detect the DTC by driving in (or performing) the ªDTC Confirmation Procedureº. Check and read the DTC
by using CONSULT-II.
During the DTC verification, be sure to connect CONSULT-II to the vehicle in DATA MONITOR (AUTO TRIG)
mode and check real time diagnosis results.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-559.
In case the ªDTC Confirmation Procedureº is not available, perform the ªOverall Function Checkº instead. The
DTC cannot be displayed by this check, however, this simplified ªcheckº is an effective alternative.
The ªNGº result of the ªOverall Function Checkº is the same as the DTC detection.
STEP VTake the appropriate action based on the results of STEP I through IV.
If the malfunction code is indicated, proceed to TROUBLE DIAGNOSIS FOR DTC PXXXX.
If the normal code is indicated, proceed to the Basic Inspection, EC-536. Then perform inspections according to
the Symptom Matrix Chart. Refer to EC-541.
STEP VIIdentify where to begin diagnosis based on the relationship study between symptom and possible causes.
Inspect the system for mechanical binding, loose connectors or wiring damage using (tracing) ªHarness Layoutsº.
Gently shake the related connectors, components or wiring harness with CONSULT-II set in ªDATA MONITOR
(AUTO TRIG)º mode.
Check the voltage of the related ECM terminals or monitor the output data from the related sensors with CON-
SULT-II. Refer to EC-554 or EC-551.
The ªDiagnostic Procedureº in EC section contains a description based on open circuit inspection. A short circuit
inspection is also required for the circuit check in the Diagnostic Procedure. For details, refer to GI-24, ªCircuit
Inspectionº.
Repair or replace the malfunction parts.
If the malfunctioning part cannot be detected, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT
INCIDENTº, EC-559.
STEP VIIOnce you have repaired the circuit or replaced a component, you need to run the engine in the same conditions
and circumstances which resulted in the customer's initial complaint.
Perform the ªDTC Confirmation Procedureº and confirm the normal code (DTC P0000 or 0505) is detected. If the
incident is still detected in the final check, perform STEP VI by using a different method from the previous one.
Before returning the vehicle to the customer, be sure to erase the unnecessary (already fixed) DTC in ECM.
(Refer to EC-522.)
TROUBLE DIAGNOSIS Ð INTRODUCTIONYD
Work Flow (Cont'd)
EC-535

Symptom Matrix ChartNJEC1257
SYSTEM Ð Basic engine
control systemSYMPTOM
Reference page
Feature of symptom, Check pointHARD/NO START/RESTART
(EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
KNOCK/DETONATION
LACK OF POWER
POOR ACCELERATION
HI IDLE
LOW IDLE NO START (with first firing)
NO START (without first firing)
HARD TO START WHEN ENGINE IS COLD
HARD TO START WHEN ENGINE IS HOT
AT IDLE
DURING DRIVING
WHEN DECELERATINGWarranty symptom code AA AB AC AD AE AF
Electronic control fuel injec-
tion pump mainframe4444444445544 Ð *1
Injection nozzle3333333334433EC-509 *2
Glow system1111 1EC-677
Engine body3333333 344 3EMsection *3
EGR system3 3 EC-686
Air cleaner and ducts 3 3 MA section *4
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*1: Fuel injection system malfunction or fuel injection timing control system malfunction may be the cause.
*2: Depends on open-valve pressure and spray pattern.
*3: Caused mainly by insufficient compression pressure.
*4: Symptom varies depending on off-position of air duct, etc.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart
EC-541

SYSTEM Ð Basic engine control
systemSYMPTOM
Reference page
Feature of symptom, Check pointROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEAT/HIGH ENGINE COOLANT TEMPERATURE
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
ABNORMAL SMOKE COLOR
DEAD BATTERY (UNDER CHARGE)
Malfunction indicator illuminates.
Can be detected by CONSULT-II?BLACK SMOKE
WHITE SMOKEWarranty symptom code AG AH AJ AK AL AM AP HA
Electronic control fuel injection
pump mainframe44345433Ð*1
Injection nozzle 3 3 3 4 3 EC-509 *2
Glow system 1 1 EC-677
Engine body 3 3 3 3 3 3 EM section *3
EGR system 3 EC-686
Air cleaner and ducts 3 3 MA section *4
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*1: Fuel injection system malfunction or fuel injection timing control system malfunction may be the cause.
*2: Depends on open-valve pressure and spray pattern.
*3: Caused mainly by insufficient compression pressure.
*4: Symptom varies depending on off-position of air duct, etc.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-542

SYSTEM Ð ENGINE CONTROL system
Malfunction
SYMPTOM
Reference page
Feature of symptom, Check pointHARD/NO START/RESTART
(EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
KNOCK/DETONATION
LACK OF POWER
POOR ACCELERATION
HI IDLE
LOW IDLE NO START (with first firing)
NO START (without first firing)
HARD TO START WHEN ENGINE IS COLD
HARD TO START WHEN ENGINE IS HOT
AT IDLE
DURING DRIVING
WHEN DECELERATINGWarranty symptom code AA AB AC AD AE AF
ENGINE CONTROL
Electronic control fuel injection
pump circuit*a, *b 1 1
111111111
Ð
*c, *d
Mass air flow sensor circuit*a, *c
111
EC-566
*b
Engine coolant temperature sensor
circuit*a, *b 1 1 1 1 EC-572 *1
Vehicle speed sensor circuit *a, *b 1 EC-593
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*1: Compensation according to engine coolant temperature does not function.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-543

SYSTEM Ð ENGINE CONTROL system
Malfunction
SYMPTOM
Reference page
Feature of symptom, Check pointROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEAT/HIGH ENGINE COOLANT TEMPERATURE
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
ABNORMAL SMOKE COLOR
DEAD BATTERY (UNDER CHARGE)
Malfunction indicator illuminates.
Can be detected by CONSULT-II?BLACK SMOKE
WHITE SMOKEWarranty symptom code AG AH AJ AK AL AM AP HA
ENGINE CONTROL
Electronic control fuel injection pump
circuit*a, *b 1 1 1
11 Ð
*c, *d 1
Mass air flow sensor circuit*a, *c
1 EC-566
*b 1
Engine coolant temperature sensor cir-
cuit*a, *b 1 1 1 1 1 EC-572 *1
Vehicle speed sensor circuit *a, *b 1 EC-593
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*1: Compensation according to engine coolant temperature does not function.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-544

SYSTEM Ð ENGINE CONTROL system
Malfunction
SYMPTOM
Reference page
Feature of symptom, Check pointHARD/NO START/RESTART
(EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
KNOCK/DETONATION
LACK OF POWER
POOR ACCELERATION
HI IDLE
LOW IDLE NO START (with first firing)
NO START (without first firing)
HARD TO START WHEN ENGINE IS COLD
HARD TO START WHEN ENGINE IS HOT
AT IDLE
DURING DRIVING
WHEN DECELERATINGWarranty symptom code AA AB AC AD AE AF
ENGINE CONTROL
Fuel cut system line*a, *c
EC-612
*b 1 1 1 1 *2
Accelerator position sensor circuit *a, *b 1 1 1 EC-577
Crankshaft position sensor (TDC)
circuit*a, *b
111111111EC-587
*d
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*2: Engine runs on after turning ignition switch OFF.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-545