Diagnosis and Repair Work Flow

Diagnostic Work Sheet

Diagnostic Work Sheet

DESCRIPTION

There are many operating conditions that lead to the malfunction of engine components. A good grasp of such conditions can make troubleshooting faster and more accurate.

In general, each customer feels differently about symptoms. It is important to fully understand the symptoms or conditions for a customer complaint.

Utilize a diagnostic worksheet like the WORKSHEET SAMPLE below in order to organize all the information for troubleshooting.

Some conditions may cause the MIL to illuminate or blink, and DTC to be detected. Examples:

• Nissan Sentra 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

Work Flow

Work Flow

OVERALL SEQUENCE

*1: Include 1st trip DTC.

*2: Include 1st trip freeze frame data.

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 “Diagnostic Work Sheet”. (Refer to Diagnostic Work Sheet.)

   Malfunction information, obtained>>

   GO TO 2.

2. CHECK DTC

   1. Check DTC of “ALL DTC Reading”.

   2. Perform the following procedure if DTC is displayed.

      • Record DTC and freeze frame data. (Print them out with CONSULT or GST.)

      • Erase only DTC of “ENGINE”. Refer to How to Erase DTC and 1st Trip DTC in Diagnosis Description.

      • Study the relationship between the cause detected by DTC and the symptom described by the customer. (Symptom Table is useful. Refer to Symptom Table. )

   Is any symptom described and is any DTC 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 Symptom Description and Fail-safe.

   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 Symptom Description and Fail-safe.

   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 DTC Inspection Priority Chart and determine trouble 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 Manual. 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 CONFIRMATION PROCEDURE.

   Is DTC detected?

   YES >>

   GO TO 10.

   NO >>

   Check according to Intermittent Incident.

6. PERFORM BASIC INSPECTION

   Refer to Work Procedure.

   Do you have CONSULT?

   YES >>

   GO TO 7.

   NO >>

   GO TO 9.

7. PERFORM SPEC IN DATA MONITOR MODE

   With CONSULT

   Check that “MASS AIR FLOW SENSOR (Hz) B1”, “B/FUEL SCHDL”, and “A/F ALPHA-B1” are within the SP value using “SPEC” in “DATA MONITOR” mode with CONSULT. Refer to Component Function Check.

   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 Diagnosis Procedure.

   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 Symptom Table. 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 Circuit Inspection.

    Is a malfunctioning part detected?

    YES >>

    GO TO 11.

    NO >>

    Monitor input data from related sensors or check voltage of related ECM terminals using CONSULT. Refer to Physical Values.

11. REPAIR OR REPLACE THE MALFUNCTIONING PART

    With CONSULT

    1. Repair or replace the malfunctioning part.

    2. Reconnect parts or connectors disconnected during Diagnosis Procedure again after repair and replacement.

    3. Check DTC. If DTC is displayed, erase it. Refer to How to Erase DTC and 1st Trip DTC in Diagnosis Description.

    >>

    GO TO 12.

12. FINAL CHECK

    When DTC was detected in step 2, perform DTC CONFIRMATION PROCEDURE or Component 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.

    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 Nissan Sentra vehicle to the customer, make sure to erase unnecessary DTC in ECM. (Refer to “How to Erase DTC and 1st Trip DTC” in Diagnosis Description.)

    NO-2 >>

    I/M examination, requested from the customer: GO TO 13.

13. PREPARE FOR I/M EXAMINATION

    1. Set SRT codes. Refer to Work Procedure.

    2. Erase permanent DTCs. Refer to Work Procedure.

    >>

    INSPECTION END.

Additional Service When Replacing Ecm

Work Procedure

Work Procedure

Description

When replacing ECM, the following procedure must be performed.

CAUTION:

When replacing the ECM, always replace it with a new one.

The functions controlled by the ECM does not operate properly in case of reuse of the ECM from another Nissan Sentra vehicle.

PROGRAMMING OPERATION

Note:

After replacing with a blank ECM, programming is required to write ECM information. Be sure to follow the procedure to perform the programming.

Work Procedure