DTC and MI Detection Logic
When 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-7.
Diagnostic Trouble Code (DTC)
HOW TO READ DTC
The 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: 0102, 0407, 1004, etc.
With CONSULT-II
CONSULT-II displays the DTC in ªSELF-DIAG RESULTSº mode. Examples: ªCRANK POS SEN (TDC)º, etc.
IOutput 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 DTC
How to erase DTC (
With CONSULT-II)
1. 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.)
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)
1. 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-36.)
The emission related diagnostic information in the ECM can be erased by changing the diagnostic test mode.
SEF371Y
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
EC-33
IIf the battery is disconnected, the emission-related diagnostic information will be lost after approx.
24 hours.
IErasing the emission-related diagnostic information using CONSULT-II is easier and quicker than
switching the diagnostic test mode using the data link connector.
NATS (Nissan Anti-Theft System)
IIf the security indicator lights up with the ignition switch in
the ªONº position or ªNATS MALFUNCTIONº is displayed
on ªSELF-DIAG RESULTSº screen, perform self-diagnostic
results mode with CONSULT-II using NATS program card.
Refer to ªNATS (Nissan Anti-Theft System)º in EL section.
IConfirm no self-diagnostic results of NATS is displayed
before touching ªERASEº in ªSELF-DIAG RESULTSº mode
with CONSULT-II.
IWhen replacing ECM, initialization of NATS system and
registration of all NATS ignition key IDs must be carried out
with CONSULT-II using NATS program card.
Therefore, be sure to receive all keys from vehicle owner.
Regarding the procedures of NATS initialization and NATS
ignition key ID registration, refer to CONSULT-II operation
manual, NATS.
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 with-
out the engine running. This is a bulb check.
IIf the MI does not light up, refer to EL section (ªWARNING
LAMPS AND CHIMEº) or see EC-291.
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.
If MI illuminates or blinks irregularly after starting engine,
water may have accumulated in fuel filter. Drain water from
fuel filter. Refer to MA section.
SEF252Z
SAT652J
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
Diagnostic Trouble Code (DTC) (Cont'd)
EC-34
Relationship between MI, DTC, CONSULT-II and driving patterns
*1: When a malfunction is detected,
MI will light up.
*2: MI will not light up after ignition
switch is turned OFF.
*3: When a malfunction is detected
for the first time, the DTC will be
stored in ECM.*4: The DTC will not be displayed any
longer after vehicle is driven 40
times without the same malfunc-
tion. (The DTC still remain in
ECM.)*5: Other screens except SELF-DIAG-
NOSTIC RESULTS & DATA
MONITOR (AUTO TRIG) cannot
display the malfunction. DATA
MONITOR (AUTO TRIG) can dis-
play the malfunction at the
moment it is detected.
PBIB0589E
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
Malfunction Indicator (MI) (Cont'd)
EC-38
ENGINE CONTROL COMPONENT PARTS/CONTROL
SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
SELF-DIAG
RESULTSDATA MONI-
TORACTIVE
TEST
ENGINE CONTROL COMPONENT PARTS
INPUTEngine coolant temperature sensor X X
Vehicle speed sensor X X
Accelerator position sensor X X X
Accelerator position switch X X
Accelerator switch (F/C) X X
Crankshaft position sensor (TDC) X X
Ignition switch (start signal) X
Park/Neutral position (PNP) switch X
Battery voltage X
Air conditioner switch X
Mass air flow sensor X X
Stop lamp switch X X
Heat up switch X
Charge air pressure sensor X
OUTPUTGlow relayXX
EGR volume control valve X X X
Cooling fan relay X X X
Air conditioner relay X
Variable nozzle turbocharger control solenoid valve X
Swirl control valve control solenoid valve X X
X: Applicable
SELF-DIAGNOSTIC MODE
Regarding items detected in ªSELF-DIAG RESULTSº mode,
refer to ªTROUBLE DIAGNOSIS Ð INDEXº, EC-7.
DATA MONITOR MODE
Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
CKPS×RPM (TDC)
[rpm]qqIThe engine speed computed from the
crankshaft position sensor (TDC) signal
is displayed.
CMPS×RPM×PUMP
[rpm]qqIThe engine speed computed from the
pulse signal sent from electronic control
fuel injection pump is displayed.
COOLAN TEMP/S
[ÉC] or [ÉF]
qqIThe engine coolant temperature (deter-
mined by the signal voltage of the engine
coolant temperature sensor) is displayed.IWhen the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the ECM
is displayed.
VHCL SPEED SE
[km/h] or [mph]qqIThe vehicle speed computed from the
vehicle speed sensor signal is displayed.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
CONSULT-II (Cont'd)
EC-40
Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
FUEL TEMP SEN
[ÉC] or [ÉF]qqIThe fuel temperature (sent from elec-
tronic control fuel injection pump) is dis-
played.
ACCEL POS SEN [V]
qqIThe accelerator position sensor signal
voltage is displayed.
FULL ACCEL SW
[ON/OFF]qqIIndicates [ON/OFF] condition from the
accelerator position switch signal.
ACCEL SW (FC)
[OPEN/CLOSE]qqIIndicates [OPEN/CLOSE] condition from
the accelerator switch (FC) signal.
OFF ACCEL SW
[ON/OFF]qqIIndicates [ON/OFF] condition from the
accelerator position switch signal.
SPILL/V [ÉCA]
qIThe control position of spill valve (sent
from electronic control fuel injection
pump) is displayed.
BATTERY VOLT [V]
qqIThe power supply voltage of ECM is dis-
played.
P/N POSI SW
[ON/OFF]qqIIndicates [ON/OFF] condition from the
park/neutral position switch signal.
START SIGNAL
[ON/OFF]qqIIndicates [ON/OFF] condition from the
starter signal.IAfter starting the engine, [OFF] is dis-
played regardless of the starter signal.
AIR COND SIG
[ON/OFF]qqIIndicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
BRAKE SW [ON/OFF]
qqIIndicates [ON/OFF] condition from the
stop lamp switch signal.
IGN SW
[ON/OFF]qqIIndicates [ON/OFF] condition from igni-
tion switch signal.
WARM UP SW
[ON/OFF]qIIndicates [ON/OFF] condition from the
heat up switch signal.
MAS AIR/FL SE [V]
qqIThe signal voltage of the mass air flow
sensor is displayed.IWhen the engine is stopped, a certain
value is indicated.
DECELER F/CUT
[ON/OFF]qIThe [ON/OFF] condition from decelera-
tion fuel cut signal (sent from electronic
control fuel injection pump) is displayed.
INJ TIMG C/V [%]
qIThe duty ratio of fuel injection timing
control valve (sent from electronic control
fuel injection pump) is displayed.
AIR COND RLY
[ON/OFF]qIIndicates the control condition of the air
conditioner relay (determined by ECM
according to the input signals).
GLOW RLY [ON/OFF]
qIThe glow relay control condition (deter-
mined by ECM according to the input
signal) is displayed.
COOLING FAN
[ON/OFF]
qIIndicates the control condition of the
cooling fans (determined by ECM
according to the input signal).
ION ... Operates.
OFF ... Stopped.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
CONSULT-II (Cont'd)
EC-41
Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
EGR VOL CON/V
[step]
qIIndicates the EGR volume control value
computed by the ECM according to the
input signals.
IThe opening becomes larger as the
value increases.
VNT S/V 1 [%]IIndicates the variable nozzle turbo-
charger control solenoid valve control
value computed by the ECM according
to the input signals.
BARO SEN [kPa]
qIThe barometric pressure (determined by
the signal voltage from the barometric
pressure sensor built into the ECM) is
displayed.
SWRL CON S/V 1
[ON/OFF]
qIThe control condition of the swirl control
valve control solenoid valve (determined
by ECM according to the input signals) is
indicated.
ION ... Swirl control valve is closed.
IOFF ... Swirl control valve is opened.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
CONSULT-II (Cont'd)
EC-42
REAL TIME DIAGNOSIS IN DATA MONITOR MODE
CONSULT-II has two kinds of triggers and they can be selected by
touching ªSETTINGº in ªDATA MONITORº mode.
1) ªAUTO TRIGº (Automatic trigger):
IThe malfunction will be identified on the CONSULT-II screen in
real time.
In other words, DTC will be displayed if the malfunction is
detected by ECM.
At the moment a malfunction is detected by ECM, ªMONITORº
in ªDATA MONITORº screen is changed to ªRecording Data ...
xx%º as shown at left, and the data after the malfunction detec-
tion is recorded. Then when the percentage reached 100%,
ªREAL-TIME DIAGº screen is displayed. If ªSTOPº is touched
on the screen during ªRecording Data ... xx%º, ªREAL-TIME
DIAGº screen is also displayed.
The recording time after the malfunction detection and the
recording speed can be changed by ªTRIGGER POINTº and
ªRecording Speedº. Refer to CONSULT-II OPERATION
MANUAL.
2) ªMANU TRIGº (Manual trigger):
IDTC will not be displayed automatically on CONSULT-II screen
even though a malfunction is detected by ECM.
DATA MONITOR can be performed continuously even though
a malfunction is detected.
Use these triggers as follows:
1) ªAUTO TRIGº
IWhile trying to detect the DTC by performing the ªDTC Confir-
mation Procedureº, be sure to select to ªDATA MONITOR
(AUTO TRIG)º mode. You can confirm the malfunction at the
moment it is detected.
IWhile narrowing down the possible causes, CONSULT-II
should be set in ªDATA MONITOR (AUTO TRIG)º mode, espe-
cially in case the incident is intermittent.
When you are inspecting the circuit by gently shaking (or twist-
ing) the suspicious connectors, components and harness in the
ªDTC Confirmation Procedureº, the moment a malfunction is
found the DTC will be displayed. (Refer to GI section, ªIncident
Simulation Testsº in ªHOW TO PERFORM EFFICIENT DIAG-
NOSIS FOR AN ELECTRICAL INCIDENTº.)
2) ªMANU TRIGº
IIf the malfunction is displayed as soon as ªDATA MONITORº is
selected, reset CONSULT-II to ªMANU TRIGº. By selecting
ªMANU TRIGº you can monitor and store the data. The data
can be utilized for further diagnosis, such as a comparison with
the value for the normal operating condition.
SEF373Y
SEF707X
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
CONSULT-II (Cont'd)
EC-44
DESCRIPTION FOR WORK FLOW
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using
the ªDIAGNOSTIC WORKSHEETº, EC-46.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II) the DTC, then erase the
DTC. Refer to EC-33.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-78.
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-56.) 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-78.
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-78.
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 XXXX.
If the normal code is indicated, proceed to the Basic Inspection, EC-50. Then perform inspections according to
the Symptom Matrix Chart. Refer to EC-56.
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-69 or EC-66.
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 section (ªCir-
cuit Inspectionº, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº).
Repair or replace the malfunction parts.
If the malfunctioning part cannot be detected, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT
INCIDENTº, EC-78.
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 No. 0505) is detected. If the inci-
dent 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-33.)
TROUBLE DIAGNOSIS Ð INTRODUCTIONZD30DDTi
Work Flow (Cont'd)
EC-49