Nissan Pathfinder (2012 year). Instruction — part 313
ENGINE CONTROL SYSTEM
EC-585
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ABBIA1111GB
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2012 Pathfinder
EC-586
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ENGINE CONTROL SYSTEM
ABBIA0440GB
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2012 Pathfinder
DIAGNOSIS AND REPAIR WORK FLOW
EC-587
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BASIC INSPECTION
DIAGNOSIS AND REPAIR WORK FLOW
Trouble Diagnosis Introduction
INFOID:0000000007799379
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 (or GST) or a circuit tester connected should be
performed. Follow the Work Flow on “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 “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.
WORK FLOW
MEF036D
SEF233G
SEF234G
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DIAGNOSIS AND REPAIR WORK FLOW
Overall Sequence
Detailed Flow
1.
GET INFORMATION FOR SYMPTOM
1. Get the detailed information from the customer about the symptom (the condition and the environment
when the incident/malfunction occurred) using the “Diagnostic Work Sheet”.
2. Ask if the customer requests I/M examination.
Malfunction information, obtained>>GO TO 2.
JSBIA0123GB
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DIAGNOSIS AND REPAIR WORK FLOW
EC-589
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No malfunction information, but a request for I/M examination>>GO TO 13.
2.
CHECK DTC
1. Check DTC.
2. Perform the following procedure if DTC is displayed.
-
Record DTC and freeze frame data. (Print them out with CONSULT or GST.)
-
Erase DTC.
-
Study the relationship between the cause detected by DTC and the symptom described by the customer.
(Symptom Matrix Chart is useful. Refer to
EC-947, "Symptom Matrix Chart"
3. Check related service bulletins for information.
Are any symptoms described and any DTCs detected?
Symptom is described, DTC is detected>>GO TO 3.
Symptom is described, DTC is not detected>>GO TO 4.
Symptom is not described, DTC is detected>>GO TO 5.
3.
CONFIRM THE SYMPTOM
Try to confirm the symptom described by the customer (except MIL ON).
Also study the normal operation and fail-safe related to the symptom. Refer to
No Load and High Engine Speed)"
.
Diagnosis Work Sheet is useful to verify the incident.
Verify relation between the symptom and the condition when the symptom is detected.
>> GO TO 5.
4.
CONFIRM THE SYMPTOM
Try to confirm the symptom described by the customer.
Also study the normal operation and fail-safe related to the symptom. Refer to Refer to
Control (at No Load and High Engine Speed)"
.
Diagnosis Work Sheet is useful to verify the incident.
Verify relation between the symptom and the condition when the symptom is detected.
>> GO TO 6.
5.
PERFORM DTC CONFIRMATION PROCEDURE
Perform DTC CONFIRMATION PROCEDURE for the displayed DTC, and then check that DTC is detected
again.
If two or more DTCs are detected, refer to
EC-555, "DTC Inspection Priority Chart"
diagnosis order.
NOTE:
• Freeze frame data is useful if the DTC is not detected.
• Perform Component Function Check if DTC CONFIRMATION PROCEDURE is not included on Service
Instruction. This simplified check procedure is an effective alternative though DTC cannot be detected during
this check.
If the result of Component Function Check is NG, it is the same as the detection of DTC by DTC CONFIR-
MATION PROCEDURE.
Is DTC detected?
YES
>> GO TO 10.
NO
>> Check according to
GI-37, "Intermittent Incident"
.
6.
PERFORM BASIC INSPECTION
Perform
Will CONSULT be used?
YES
>> GO TO 7.
NO
>> GO TO 9.
7.
PERFORM SPEC IN DATA MONITOR MODE
With CONSULT
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DIAGNOSIS AND REPAIR WORK FLOW
Check that “MAS A/F SE-B1”, “MAS A/F SE-B2”, “B/FUEL SCHDL”, “A/F ALPHA-B1” and “A/F ALPHA-B2”
are within the SP value using “SPEC” in “DATA MONITOR” mode with CONSULT. Refer to
,
EC-612, "Inspection Procedure"
.
Is the measurement value within the SP value?
YES
>> GO TO 9.
NO
>> GO TO 8.
8.
DETECT MALFUNCTIONING PART BY TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Detect malfunctioning part according to
.
Is a malfunctioning part detected?
YES
>> GO TO 11.
NO
>> GO TO 9.
9.
DETECT MALFUNCTIONING SYSTEM BY SYMPTOM TABLE
Detect malfunctioning system according to
EC-947, "Symptom Matrix Chart"
based on the confirmed symptom
in step 4, and determine the trouble diagnosis order based on possible causes and symptoms.
>> GO TO 10.
10.
DETECT MALFUNCTIONING PART BY DIAGNOSIS PROCEDURE
Inspect according to Diagnosis Procedure of the system.
NOTE:
The Diagnosis Procedure in EC section described based on open circuit inspection. A short circuit inspection
is also required for the circuit check in the Diagnosis Procedure. For details, refer to
.
Is a malfunctioning part detected?
YES
>> GO TO 11.
NO
>> Monitor input data from related sensors or check voltage of related ECM terminals using CON-
SULT. Refer to
EC-542, "CONSULT Reference Value in Data Monitor Mode"
,
.
11.
REPAIR OR REPLACE THE MALFUNCTIONING PART
1. Repair or replace the malfunctioning part.
2. Reconnect parts or connectors disconnected during Diagnosis Procedure again after repair and replace-
ment.
3. Check DTC. If DTC is displayed, erase it.
>> GO TO 12.
12.
FINAL CHECK
When DTC was detected in step 2, perform DTC CONFIRMATION PROCEDURE or Component Function
Check again, and then check that the malfunction have been completely repaired.
When symptom was described from the customer, refer to confirmed symptom in step 3 or 4, and check that
the symptom is not detected.
Is DTC detected and does symptom remain?
YES-1 >> DTC is detected: GO TO 10.
YES-2 >> Symptom remains: GO TO 6.
NO-1 >> Before returning the vehicle to the customer, always erase unnecessary DTC in ECM and TCM
(Transmission Control Module). If the completion of SRT is needed, drive vehicle under the spe-
cific driving pattern. Refer to
NO-2 >> I/M examination, requested from the customer: GO TO 13.
13.
PREPARE FOR I/M EXAMINATION
1. Set SRT codes. Refer to
2. Erase permanent DTCs. Refer to
.
>> INSPECTION END
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DIAGNOSIS AND REPAIR WORK FLOW
EC-591
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DIAGNOSTIC WORKSHEET
Description
There are many operating conditions that lead to the malfunction of
engine components. A good grasp of such conditions can make trou-
bleshooting faster and more accurate.
In general, each customer feels differently about a incident. It is
important to fully understand the symptoms or conditions for a cus-
tomer complaint.
Utilize a diagnostic worksheet like the one on the next page in order
to organize all the information for troubleshooting.
Some conditions may cause the MIL to come on steady or blink and
DTC to be detected. Examples:
• Vehicle ran out of fuel, which caused the engine to misfire.
• Fuel filler cap was left off or incorrectly screwed on, allowing fuel to
evaporate into the atmosphere.
Worksheet Sample
SEF907L
MTBL0017
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EC-592
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INSPECTION AND ADJUSTMENT
INSPECTION AND ADJUSTMENT
Basic Inspection
INFOID:0000000007358456
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 leakage
-
Air cleaner clogging
-
Gasket
3. Check that electrical or mechanical loads are not applied.
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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 to the middle of gauge.
Check that engine stays below 1,000 rpm.
5. Run engine at approximately 2,000 rpm for approximately 2 min-
utes under no load.
6. Check that no DTC is displayed with CONSULT 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.
3.
CHECK TARGET IDLE SPEED
With CONSULT
1. Run engine at approximately 2,000 rpm for approximately 2 minutes under no load.
SEF983U
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