EC-42
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ENGINE CONTROL SYSTEM
TYPE 6
System Diagram
Input/output Signal Chart
T: Transmit R: Receive Engine speed signal T R R R
ESP OFF indicator lamp signal T R
MI signal TR
Stop lamp switch signal T R
Vehicle speed signalTRR
RT
SLIP indicator lamp signal T R
Parking brake switch signalRT
Steering angle sensor signal R T
ASCD SET lamp signal TR
ASCD CRUISE lamp signal TR Signals ECMESP/TCS/ABS
control unitSteering angle
sensor4WD control
unitCombination
meter
PKIA6460E
Signals ECM TCMESP/TCS/
ABS control
unitSteering
angle sensor4WD control
unitCombination
meter
4WD mode indicator lamp signalTR
4WD warning lamp signalTR
A/C compressor feedback signal TR
A/T position indicator lamp signal T R R
A/T self-diagnosis signal R T
ABS warning lamp signal T R
Accelerator pedal position signal T R R
Brake warning lamp signal T R
Closed throttle position signal T R
Engine and A/T integratedTR
RT
ENGINE CONTROL SYSTEM
EC-43
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EC
TYPE 7
System diagram
Input/output signal chart
T: Transmit R: Receive Engine coolant temperature signal TR
Engine speed signal T R R R
ESP OFF indicator lamp signal T R
MI signal TR
O/D OFF indicator signal T R
Output shaft revolution signal R T
Overdrive control switch signal R T
P·N range signal R T
SLIP indicator lamp signal T R
Steering angle sensor signal R T
Stop lamp switch signalRT
TR
Vehicle speed signalTRR
RT
Parking brake switch signalRT
Wide open throttle position signal T R
ASCD SET lamp signal TR
ASCD CRUISE lamp signal TR Signals ECM TCMESP/TCS/
ABS control
unitSteering
angle sensor4WD control
unitCombination
meter
SKIA9999E
Signals ECM ABS actuator and electric unit (control unit) Combination meter
A/C compressor feedback signal T R
ABS warning lamp signal T R
Engine coolant temperature signal T R
Engine speed signal T R
MI signal T R
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-55
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EC
*1: 1st trip DTC No. is the same as DTC No.
*2: This number is prescribed by ISO 15031-5.
*3: In Diagnostic Test Mode II (Self-diagnostic results), this number is controlled by NISSAN.
*4: The troubleshooting for this DTC needs CONSULT-II.
*5: For models with ESP
*6: For QR25DE engine models
*7: When the fail-safe operation for both self-diagnoses occur at the same time, the MI illuminates.
DTC AND 1ST TRIP DTC
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 EC-63, "
HOW
TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION" .
For malfunctions in which 1st trip DTCs are displayed, refer to EC-53, "
EMISSION-RELATED DIAGNOSTIC
INFORMATION ITEMS" . These items are required by legal regulations to continuously monitor the system/
component. In addition, the items monitored non-continuously are also displayed on CONSULT-II.
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 II, refer to EC-74, "
WORK FLOW" . Then perform DTC Confir-
mation Procedure or Overall Function Check to try to duplicate the malfunction. If the malfunction is dupli-
cated, the item requires repair.
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
With CONSULT-II
With GST
CONSULT-II or GST (Generic Scan Tool) Examples: P0340, P0740, P0745, etc.
This DTC is prescribed by ISO 15031-5.
(CONSULT-II also displays the malfunctioning component or system.)
No Tools
The number of blinks of the MI in the Diagnostic Test Mode II (Self-Diagnostic Results) indicates the DTC.
Example: 0102, 0340 etc.
This DTC is controlled by NISSAN.
1st trip DTC No. is the same as DTC No.
Output of a DTC indicates a malfunction. However, GST or the Diagnostic Test Mode II do not indi-
cate whether the malfunction is still occurring or has occurred in the past and has returned to nor-
BRAKE SW/CIRCUIT P1805 1805 — —×EC-405
APP SEN 1/CIRC P2122 2122 — — —EC-409
APP SEN 1/CIRC P2123 2123 — — —EC-409
APP SEN 2/CIRC P2127 2127 — — —EC-416
APP SEN 2/CIRC P2128 2128 — — —EC-416
TP SENSOR P2135 2135 — — —EC-424
APP SENSOR P2138 2138 — — —EC-432
Items
(CONSULT-II screen terms)DTC*
1
SRT codeTe s t Va l v e /
Te s t L i m i t
(GST only)1st trip DTC Reference page
CONSULT-II
GST*
2ECM*3
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-57
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EC
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT
status will indicate “CMPLT” for each application system. Once set as “CMPLT”, the SRT status remains
“CMPLT” until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's
normal driving pattern; the SRT will indicate “INCMP” for these items.
NOTE:
The SRT will also indicate “INCMP” if the self-diagnosis memory is erased for any reason or if the ECM mem-
ory power supply is interrupted for several hours.
If, during the state emissions inspection, the SRT indicates “CMPLT” for all test items, the inspector will con-
tinue with the emissions test. However, if the SRT indicates “INCMP” for one or more of the SRT items the
vehicle is returned to the customer untested.
NOTE:
If MI is “ON” during the state emissions inspection, the vehicle is also returned to the customer untested even
though the SRT indicates “CMPLT” for all test items. Therefore, it is important to check SRT (“CMPLT”) and
DTC (No DTCs) before the inspection.
SRT Item
The table below shows required self-diagnostic items to set the SRT to “CMPLT”.
*: If completion of several SRTs is required, perform driving patterns (DTC confirmation procedure), one by one based on the priority for
models with CONSULT-II.
SRT Set Timing
SRT is set as “CMPLT” after self-diagnosis has been performed one or more times. Completion of SRT is
done regardless of whether the result is OK or NG. The set timing is different between OK and NG results and
is shown in the table below.
SRT item
(CONSULT-II
indication)Performance
Priority*Required self-diagnostic items to set the SRT to “CMPLT” Corresponding DTC No.
CATALYST 2 Three way catalyst function P0420
HO2S 1 Heated oxygen sensor 1 P0133
Heated oxygen sensor 1 P1143
Heated oxygen sensor 1 P1144
Heated oxygen sensor 2 P0139
Heated oxygen sensor 2 P1146
Heated oxygen sensor 2 P1147
HO2S HTR 1 Heated oxygen sensor 1 heater P0031, P0032
Heated oxygen sensor 2 heater P0037, P0038
Self-diagnosis resultExample
DiagnosisIgnition cycle
← ON → OFF ← ON → OFF ← ON → OFF ← ON →
All OK Case 1 P0400 OK (1) — (1) OK (2) — (2)
P0402 OK (1) — (1) — (1) OK (2)
P1402 OK (1) OK (2) — (2) — (2)
SRT of EGR “CMPLT” “CMPLT” “CMPLT” “CMPLT”
Case 2 P0400 OK (1) — (1) — (1) — (1)
P0402 — (0) — (0) OK (1) — (1)
P1402 OK (1) OK (2) — (2) — (2)
SRT of EGR “INCMP” “INCMP” “CMPLT” “CMPLT”
EC-58
[QR (WITH EURO-OBD)]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
OK: Self-diagnosis is carried out and the result is OK.
NG: Self-diagnosis is carried out and the result is NG.
—: Self-diagnosis is not carried out.
When all SRT related self-diagnoses showed OK results in a single cycle (Ignition OFF-ON-OFF), the SRT will
indicate “CMPLT”. → Case 1 above
When all SRT related self-diagnoses showed OK results through several different cycles, the SRT will indicate
“CMPLT” at the time the respective self-diagnoses have at least one OK result. → Case 2 above
If one or more SRT related self-diagnoses showed NG results in 2 consecutive cycles, the SRT will also indi-
cate “CMPLT”. → Case 3 above
The table above shows that the minimum number of cycles for setting SRT as “INCMP” is one (1) for each
self-diagnosis (Case 1 & 2) or two (2) for one of self-diagnoses (Case 3). However, in preparation for the state
emissions inspection, it is unnecessary for each self-diagnosis to be executed twice (Case 3) for the following
reasons:
The SRT will indicate “CMPLT” at the time the respective self-diagnoses have one (1) OK result.
The emissions inspection requires “CMPLT” of the SRT only with OK self-diagnosis results.
When, during SRT driving pattern, 1st trip DTC (NG) is detected prior to “CMPLT” of SRT, the self-diagno-
sis memory must be erased from ECM after repair.
If the 1st trip DTC is erased, all the SRT will indicate “INCMP”.
NOTE:
SRT can be set as “CMPLT” together with the DTC(s). Therefore, DTC check must always be carried out
prior to the state emission inspection even though the SRT indicates “CMPLT”.
SRT Service Procedure
If a vehicle has failed the state emissions inspection due to one or more SRT items indicating “INCMP”, review
the flowchart diagnostic sequence on the next page.
NG exists Case 3 P0400 OK OK — —
P0402 — — — —
P1402 NG — NGNG
(Consecutive
NG)
(1st trip)
DTC1st trip DTC — 1st trip DTCDTC
(= MI “ON”)
SRT of EGR “INCMP” “INCMP” “INCMP” “CMPLT” Self-diagnosis resultExample
DiagnosisIgnition cycle
← ON → OFF ← ON → OFF ← ON → OFF ← ON →
EC-60
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
How to Set SRT Code
To set all SRT codes, self-diagnosis for the items indicated above must be performed one or more times. Each
diagnosis may require a long period of actual driving under various conditions.
WITH CONSULT-II
Perform corresponding DTC Confirmation Procedure one by one based on Performance Priority in the table
on EC-57, "
SRT Item" .
WITHOUT CONSULT-II
The most efficient driving pattern in which SRT codes can be properly set is explained on the next page. The
driving pattern should be performed one or more times to set all SRT codes.
TROUBLE DIAGNOSIS
EC-73
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EC
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS010LP
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air control system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. It is essen-
tial that both input and output signals are proper and stable. At the
same time, it is important that there are no malfunctions such as vac-
uum leaks, fouled spark plugs, or other malfunctions with the engine.
It is much more difficult to diagnose an incident that occurs intermit-
tently rather than continuously. Most intermittent incidents are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the incidents. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow EC-74, "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such incidents, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A Diagnostic Worksheet like the example
on EC-76, "
Worksheet Sample" should be used.
Start your diagnosis by looking for conventional malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
MEF036D
SEF233G
SEF234G
TROUBLE DIAGNOSIS
EC-79
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EC
Basic InspectionEBS010LS
1. INSPECTION START
1. Check service records for any recent repairs that may indicate a related malfunction, or a current need for
scheduled maintenance.
2. Open engine hood and check the following:
–Harness connectors for improper connections
–Wiring harness for improper connections, pinches and cut
–Vacuum hoses for splits, kinks and improper connections
–Hoses and ducts for leaks
–Air cleaner clogging
–Gasket
3. Confirm that electrical or mechanical loads are not applied.
–Headlamp switch is OFF.
–Air conditioner switch is OFF.
–Rear window defogger switch is OFF.
–Steering wheel is in the straight-ahead position, etc.
4. Start engine and warm it up until engine coolant temperature
indicator points the middle of gauge.
Ensure engine stays below 1,000 rpm.
5. Run engine at about 2,000 rpm for about 2 minutes under no
load.
6. Make sure that no DTC is displayed with CONSULT-II or GST.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. REPAIR OR REPLACE
Repair or replace components as necessary according to corresponding Diagnostic Procedure.
>> GO TO 3
SEF983U
SEF976U
SEF977U