Infiniti Q45. Manual - part 361

TROUBLE DIAGNOSIS

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WORK FLOW
Overall Sequence

PBIB2267E

EC-84

TROUBLE DIAGNOSIS

Detailed Flow

1. 

GET INFORMATION FOR SYMPTOM

Get the detailed information from the customer about the symptom (the condition and the environment when
the incident/malfunction occurred) using the 

EC-86, "DIAGNOSTIC WORKSHEET"

 .

>> GO TO 2.

2. 

CHECK DTC*

1

1.

Check DTC*

1

 .

2.

Perform the following procedure if DTC*

1

  is displayed.

–

Record DTC*

1

  and freeze frame data*

2

 . (Print them out with CONSULT-II or GST.)

–

Erase DTC*

1

 . (Refer to 

EC-61, "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION"

.)

–

Study the relationship between the cause detected by DTC*

1

  and the symptom described by the cus-

tomer. (Symptom Matrix Chart is useful. Refer to 

EC-91

 .)

3.

Check related service bulletins for information.

Is any symptom described and any DTC detected?

Symptom is described, DTC*

1

  is displayed>>GO TO 3.

Symptom is described, DTC*

1

  is not displayed>>GO TO 4.

Symptom is not described, DTC*

1

  is displayed>>GO TO 5.

3. 

CONFIRM THE SYMPTOM

Try to confirm the symptom described by the customer (except MIL ON).
DIAGNOSIS WORK SHEET is useful to verify the incident.
Connect CONSULT-II to the vehicle in “DATA MONITOR (AUTO TRIG)” mode and check real time diagnosis
results.
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.
DIAGNOSIS WORK SHEET is useful to verify the incident.
Connect CONSULT-II to the vehicle in “DATA MONITOR (AUTO TRIG)” mode and check real time diagnosis
results.
Verify relation between the symptom and the condition when the symptom is detected.

>> GO TO 6.

TROUBLE DIAGNOSIS

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5. 

PERFORM DTC CONFIRMATION PROCEDURE

Perform DTC Confirmation Procedure for the displayed DTC*

1

 , and then make sure that DTC*

1

  is detected

again.
At this time, always connect CONSULT-II to the vehicle, and check diagnostic results in real time on “DATA
MONITOR (AUTO TRIG)”.
If two or more DTCs*

1

  are detected, refer to 

EC-88, "DTC Inspection Priority Chart"

  and determine trouble

diagnosis order.
NOTE:

●

Freeze frame data*

2

  is useful if the DTC*

1

  is not detected.

●

Perform Overall Function Check if DTC Confirmation Procedure is not included on Service Manual. This
simplified check procedure is an effective alternative though DTC*

1

  cannot be detected during this check.

If the result of Overall Function Check is NG, it is the same as the detection of DTC*

1

  by DTC Confirma-

tion Procedure.

Is DTC*

1

  detected?

Yes

>> GO TO 10.

No

>> Check according to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

6. 

PERFORM BASIC INSPECTION

Perform 

EC-71, "Basic Inspection"

 .

With CONSULT-II>>GO TO 7.
Without CONSULT-II>>GO TO 9.

7. 

PERFORM DATA MONITOR (SPEC) MODE

 With CONSULT-II

Make sure that “MAS A/F SE-B1”, “B/FUEL SCHDL”, and “A/F
ALPHA-B1”, “A/F ALPHA-B2” are within the SP value using CON-
SULT-II “DATA MONITOR (SPEC)” mode. Refer to 

EC-136, "Diag-

nostic Procedure"

 .

Are they 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 

EC-135, "TROUBLE DIAGNOSIS - SPECIFICATION VALUE"

 .

Is malfunctioning part detected?

Yes

>> GO TO 11.

No

>> GO TO 9.

9. 

DETECT MALFUNCTIONING SYSTEM BY SYMPTOM MATRIX CHART

Detect malfunctioning system according to 

EC-91, "Symptom Matrix Chart"

  based on the confirmed symptom

in step 4, and determine the trouble diagnosis order based on possible causes and symptom.

>> GO TO 10.

SEF601Z

EC-86

TROUBLE DIAGNOSIS

10. 

DETECT MALFUNCTIONING PART BY DIAGNOSTIC PROCEDURE

Inspect according to Diagnostic Procedure of the system.

NOTE:
The Diagnostic Procedure in EC section described based on open circuit inspection. A short circuit inspection
is also required for the circuit check in the Diagnostic Procedure. For details, refer to Circuit Inspection in 

GI-

26, "How to Perform Efficient Diagnosis for an Electrical Incident"

 .

Is malfunctioning part detected?

Yes

>> GO TO 11.

No

>> Monitor input data from related sensors or check voltage of related ECM terminals using CON-

SULT-II. Refer to 

EC-129, "CONSULT-II Reference Value in Data Monitor Mode"

 , 

EC-105, "ECM

Terminals and Reference Value"

 .

11. 

REPAIR OR REPLACE THE MALFUNCTIONING PART

1.

Repair or replace the malfunctioning part.

2.

Reconnect parts or connectors disconnected during Diagnostic Procedure again after repair and replace-
ment.

3.

Check DTC. If DTC is displayed, erase it, refer to 

EC-61, "HOW TO ERASE EMISSION-RELATED DIAG-

NOSTIC INFORMATION"

 .

>> GO TO 12.

12. 

FINAL CHECK

When DTC was detected in step 2, perform DTC Confirmation Procedure or Overall Function Check again,
and then make sure that the malfunction have been repaired securely.
When symptom was described from the customer, refer to confirmed symptom in step 3 or 4, and make sure
that the symptom is not detected.

OK or NG

NG (DTC*

1

  is detected)>>GO TO 10.

NG (Symptom remains)>>GO TO 6.
OK

>> 1. Before returning the vehicle to the customer, make sure to erase unnecessary DTC*

1

  in ECM

and TCM (Transmission Control Module). (Refer to 

EC-61, "HOW TO ERASE EMISSION-

RELATED DIAGNOSTIC INFORMATION"

  and 

AT-39, "HOW TO ERASE DTC"

 .)

2. If the completion of SRT is needed, drive vehicle under the specific driving pattern. Refer to 

EC-

58, "Driving Pattern"

 .

3. INSPECTION END

*1: Include 1st trip DTC.
*2: Include 1st trip freeze frame data.

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.

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