Lan System: Other Nissan Armada I facelift

Condition of Error Detection

"U1000" or "U1001" is indicated on SELF-DIAG RESULTS on CONSULT-III if CAN communication signal is not transmitted or received between units for 2 seconds or more.

CAN COMMUNICATION SYSTEM ERROR

1. CAN communication line open (CAN-H, CAN-L, or both)
2. CAN communication line short (ground, between CAN communication lines, other harnesses)
3. Error of CAN communication control circuit of the unit connected to CAN communication line

WHEN "U1000" OR "U1001" IS INDICATED EVEN THOUGH CAN COMMUNICATION SYSTEM IS NORMAL

1. Removal/installation of parts: Error may be detected when removing and installing CAN communication unit and related parts while turning the ignition switch ON. (A DTC except for CAN communication may be detected.)
2. Fuse blown out (removed): CAN communication of the unit may cease.
3. Voltage drop: Error may be detected if voltage drops due to discharged battery when turning the ignition switch ON (Depending on the control unit which carries out CAN communication).
4. Error may be detected if the power supply circuit of the control unit, which carries out CAN communication, malfunctions (Depending on the control unit which carries out CAN communication).
5. Error may be detected if reprogramming is not completed normally.

Note. CAN communication system is normal if "U1000" or "U1001" is indicated on SELF-DIAG RESULTS of CONSULT-III under the above conditions. Erase the memory of the self-diagnosis of each unit.

ERROR EXAMPLE

Note. Each vehicle differs in symptom of each unit under fail-safe mode and CAN communication line wiring. Refer to " ABBREVIATION LIST " for the unit abbreviation.

Example: TCM branch line open circuit

Scheme 27

SYMPTOM CHART

Example: Data link connector branch line open circuit

Scheme 28

SYMPTOM CHART

Note. When data link connector branch line is open, transmission and reception of CAN communication signals are not affected. Therefore, no symptoms occur. However, be sure to repair malfunctioning circuit. When data link connector branch line is open, "ECU list" displayed on the CONSULT-III "CAN DIAG SUPPORT MNTR" may be the same as when the CAN communication line has short-circuit. However, symptoms differ depending on the case. See below chart for the differences.

SYMPTOM DIFFERENCE

Example: Main Line Between Data Link Connector and ABS Actuator and Electric Unit (Control Unit) Open Circuit

Scheme 29

SYMPTOM CHART

Example: CAN-H, CAN-L Harness Short Circuit

Scheme 30

SYMPTOM CHART

Self-Diagnosis

DTC CHART

How to Use CAN Communication Signal Chart

The CAN communication signal chart lists the signals needed for trouble diagnosis. It is useful for detecting the root cause by finding a signal related to the symptom, and by checking transmission and reception unit.

Scheme 31

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INTERVIEW WITH CUSTOMER

Interview with the customer is important to detect the root cause of CAN communication system errors and to understand vehicle condition and symptoms for proper trouble diagnosis.

Points in interview

1. What: Parts name, system name
2. When: Date, Frequency
3. Where: Road condition, Place
4. In what condition: Driving condition/environment
5. Result: Symptom

Note. Check normal units as well as error symptoms. Example: Circuit between ECM and the combination meter is judged normal if the customer indicates tachometer functions normally. When a CAN communication system error is present, multiple control units may malfunction or go into fail-safe mode. Indication of the combination meter is important to detect the root cause because it is the most obvious to the customer, and it performs CAN communication with many units.

CREATE INTERVIEW SHEET

Fill out the symptom described by the customer, vehicle condition, and CAN system type on the interview sheet.

Interview Sheet (Example)

Scheme 33

COLLECT DATA

Collect CONSULT-III Data

Print out or save the following CONSULT-III data.

1. SELF-DIAG RESULTS
2. CAN DIAG SUPPORT MNTR ("ECU list" included)

Note. Some items may not be needed depending on CAN system type of vehicle.

Scheme 34

Create On-board Diagnosis Copy Sheet

Display the trouble diagnosis result of CAN communication with the on-board diagnosis function on the vehicle monitor, etc. Copy them on the on-board diagnosis copy sheet.

Note. For some models, CAN communication diagnosis result is received from the vehicle monitor. (CONSULT-III is not available.)

Scheme 35

DETECT THE ROOT CAUSE

Identify the root cause using the created diagnosis sheet.

Identifying the root cause

1. Draw a line on the diagnosis sheet to indicate the possible cause. Narrow the search. NOTE: Color-code when drawing lines. Do not draw a line onto a existing line.
2. Drawing a line is not necessary if the circuit is shorted. Refer to "PRESENT ERROR - SHORT CIRCUIT -", "PAST ERROR - SHORT CIRCUIT -".

Refer to the following for details of the trouble diagnosis procedure.

1. "PRESENT ERROR - OPEN CIRCUIT -"
2. "PRESENT ERROR - SHORT CIRCUIT -"
3. "PAST ERROR - OPEN CIRCUIT -"
4. "PAST ERROR - SHORT CIRCUIT -"

Note. When the root cause appears to be a branch line or short circuit, be sure to check the control unit as well as the communication line.

Present Error - Open Circuit

Identify the error circuit using information from the "CAN DIAG SUPPORT MNTR" ("ECU list" included).

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Scheme 38

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Scheme 40

Scheme 41

1. ECU list: Check the items indicated in "ECU list". Draw a line on the diagnosis sheet to indicate the error circuit. NOTE: CAN communication line has no error if units other than Diag on CAN units are not indicated. An error may be on the power supply of the control unit, DDL1 line or DDL2 line. "TCM" which is Diag on CAN unit, is not indicated on "ECU list". This indicates that DLC is not receiving a signal from TCM. Draw a line to indicate an error between DLC and TCM (line 1-a in the figure below). NOTE: Diag on CAN units are not indicated on the "ECU list" when the CAN line between Diag on CAN unit and the data link connector is open. For a description of Diag on CAN, refer to " «DESCRIPTION»(ref-320184-S05838678002009071300000) ".
2. CAN DIAG SUPPORT MNTR: Check each item on "CAN DIAG SUPPORT MNTR". Draw a line on the diagnosis sheet to indicate the error circuit. Reception item of "ECM": On "TCM", "UNKWN" is indicated. This means ECM cannot receive the signal from TCM. Draw a line to indicate an error between ECM and TCM (line 2-a in (Scheme 38) ). NOTE: If "UNKWN" is indicated on "TRANSMIT DIAG", then the control unit cannot transmit CAN communication signal to each unit. Draw a line between the control unit and the splice. Reception item of "AFS": On "TCM", "UNKWN" is indicated. This means AFS cannot receive the signal from TCM. Draw a line to indicate an error between AFS and TCM (line 2-b in (Scheme 38) ). Reception item of "AV": "UNKWN" is not indicated. This indicates normal communication between AV and its receiving units. Do not draw any line. Reception item of "BCM": On "TCM", "UNKWN" is indicated. This means BCM cannot receive the signal from TCM. Draw a line to indicate an error between BCM and TCM (line 2-d in (Scheme 39) ). Reception item of "EPS" and "I-KEY": "UNKWN" is not indicated. This indicates normal communication between EPS and I-KEY and their receiving units. Do not draw any line. NOTE: On CAN DIAG SUPPORT MNTR (without PAST), "UNKWN" is indicated even though the item is not used in the trouble diagnosis. For the details of each item on CAN diagnostic support monitor, refer to " «CAN DIAGNOSTIC SUPPORT MONITOR»(ref-320184-S17255580442009071300000) ". Reception item of "M&A": On "TCM", "UNKWN" is indicated. This means M&A cannot receive the signal from TCM. Draw a line to indicate an error between M&A and TCM (line 2-f in (Scheme 40) ). Reception item of "ADP": On "TCM", "UNKWN" is indicated. This means ADP cannot receive the signal from TCM. Draw a line to indicate an error between ADP and TCM (line 2-g in (Scheme 40) ). Reception item of "ABS": "UNKWN" is not indicated. This indicates normal communication between ABS and its receiving units. Do not draw any line. Reception item of "IPDM-E": "UNKWN" is not indicated. This indicates normal communication between IPDM-E and its receiving units. Do not draw any line.
3. Based on information received from "CAN DIAG SUPPORT MNTR", place a check mark on the known good CAN communication line between ECM and IPDM-E. Through the previous procedure, the circuit between ADP splice and TCM has the most amount of lines (shade 3-a in the figure below). Place a check mark on the known good lines to establish the error circuit. Reception item of "IPDM-E": On "ECM", "OK" is indicated. IPDM-E communicates normally with ECM. Put a check mark on the normal circuit between ECM and IPDM-E (check mark 3-b in (Scheme 41) ).
4. Through the above procedure, the error is detected in the TCM branch line (shaded in the figure below). NOTE: For abbreviations, refer to " «ABBREVIATION LIST»(ref-320184-S14512171892009071300000) ".
5. Perform the inspection for the detected error circuit. For the inspection procedure, refer to " «MALFUNCTION AREA CHART»(ref-320184-S30629379402009071300000) ".

Present Error - Short Circuit

When the symptoms listed below exist, a short circuit of the CAN communication line is a possible cause.

Received data

SYMPTOMS LIST

Error symptom

1. Most the units connected to the CAN communication system go into fail-safe mode or are deactivated.

Inspection procedure

Scheme 42

1. Refer to " «MALFUNCTION AREA CHART»(ref-320184-S30629379402009071300000) ".

Past Error - Open Circuit

Review CAN communication signal chart based on information received from the interview with the customer and on past error information from SELF-DIAG RESULTS and CAN DIAG SUPPORT MNTR.

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Scheme 47

Scheme 48

1. SELF-DIAG RESULTS: Inspect the control units indicating "U1000" or "U1001" on SELF-DIAG RESULTS.
2. CAN DIAG SUPPORT MNTR (with PAST): Check the CAN DIAG SUPPORT MNTR (with PAST) of units indicating "U1000" or "U1001" on SELF-DIAG RESULTS. Draw a line on the diagnosis sheet to indicate the possible error circuit. NOTE: For the details of each indication on CAN DIAG SUPPORT MNTR, refer to " «CAN DIAGNOSTIC SUPPORT MONITOR»(ref-320184-S17255580442009071300000) ". Reception item of "ECM": "VDC/TCS/ABS", "3" is indicated in the "PAST". This means ECM could not receive the signal from ABS in the past. Draw a line between ECM and ABS (line 2-a in the figure below). Reception item of "M&A": "VDC/TCS/ABS", "3" is indicated in the "PAST". This means M&A could not receive the signal from ABS in the past. Draw a line between M&A and ABS (line 2-b in the figure below). Reception item of "TCM": "VDC/TCS/ABS", "3" is indicated in the "PAST". This means TCM could not receive the signal from ABS in the past. Draw a line between TCM and ABS (line 2-c in (Scheme 45) ).
3. CAN DIAG SUPPORT MNTR (without PAST): Check the CAN DIAG SUPPORT MNTR (without PAST) of units indicating "U1000" or "U1001" on SELF-DIAG RESULTS. Draw a line on the diagnosis sheet to indicate the possible error circuit. NOTE: While an error occurred in the past according to SELF-DIAG RESULTS, it is unclear which signal is not received. Assume that errors were detected from all reception items. Draw a single line among the unit and all reception items. (Work flow differs from CAN DIAG SUPPORT MNTR (with PAST).) Reception item of "EPS": Assume that the unit could not receive the signals from ECM, ABS, and M&A. Draw a line among EPS, ECM, ABS, and M&A (line 3-a in (Scheme 46) ). Reception item of "ABS": Assume that the unit could not receive the signal from ECM. Draw a line between ABS and ECM (line 3-b in (Scheme 46) ).
4. Search for the possible cause using CAN communication signal chart using information from the interview with the customer. NOTE: For the details of CAN communication signal, refer to " «CAN COMMUNICATION SIGNAL CHART»(ref-320184-S14929194302009071300000) ". ABS warning lamp turned ON and speedometer did not move: This means that "ABS warning lamp signal" and "Vehicle speed signal" could not communicate between M&A and ABS (4-a in (Scheme 47) ). The tachometer moved normally: This means that "Engine speed signal" could communicate normally between ECM and M&A (4-b in (Scheme 47) ).
5. Fill out the diagnosis sheet based on information from step 4. The ABS warning lamp turned ON and speedometer did not move: Assume that a possible cause is no communication between M&A and ABS. Draw a line between M&A and ABS. (Line 5-a in (Scheme 48) ). The tachometer moved normally: Put check marks between ECM and M&A. The circuit between ECM and M&A is functioning properly (check marks 5-b in (Scheme 48) ).
6. The circuit which has the most amount of lines are the possible cause. Error is detected from ABS actuator and electric unit (control unit) branch line (shaded in (Scheme 49) ). NOTE: For abbreviations, refer to " «ABBREVIATION LIST»(ref-320184-S14512171892009071300000) ".
7. Perform the inspection procedure for the possible cause. Refer to " «MALFUNCTION AREA CHART»(ref-320184-S30629379402009071300000) ".

Past Error - Short Circuit

When the symptoms listed below exist, a short circuit of the CAN communication line is a possible cause.

SYMPTOMS LIST

Scheme 49

Caution

1. This Service Information describes information peculiar to a vehicle, sheets for trouble diagnosis, and inspection procedures.
2. For trouble diagnosis procedure, refer to " «TROUBLE DIAGNOSIS PROCEDURE»(ref-320184-S11226594202009071300000) ".

Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT PRE-TENSIONER"

The Supplemental Restraint System such as "AIR BAG" and "SEAT BELT PRE-TENSIONER", used along with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.

Information necessary to service the system safely is included in SRS AIRBAG and SEAT BELTS articles.

CAN Communication Signal Chart

Refer to " HOW TO USE CAN COMMUNICATION SIGNAL CHART " for how to use CAN communication signal chart.

Note. Refer to " ABBREVIATION LIST " for the abbreviations of the connecting units.

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Note. CAN data of the air bag diagnosis sensor unit is not used by usual service work, thus it is omitted.

MONITOR ITEM LIST (CONSULT-III)

ECM

MONITOR ITEM LIST - ECM

TCM

Note. Replace the unit when "NG" is indicated on the "INITIAL DIAG".

MONITOR ITEM LIST - TCM

Driver Seat Control Unit

MONITOR ITEM LIST - DRIVER SEAT CONTROL UNIT

AV Control Unit

MONITOR ITEM LIST - AV CONTROL UNIT

BCM

Note. Replace the unit when "NG" is indicated on the "INITIAL DIAG".

MONITOR ITEM LIST - ECM

A/C Auto Amp

MONITOR ITEM LIST - A/C AUTO AMP

Intelligent Key Unit

MONITOR ITEM LIST - INTELLIGENT KEY UNIT

Combination Meter

MONITOR ITEM LIST - COMBINATION METER

Transfer Control Unit

MONITOR ITEM LIST - COMBINATION METER

ABS Actuator and Electric Unit (Control Unit)

MONITOR ITEM LIST - ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)

IPDM E/R

MONITOR ITEM LIST - IPDM E/R

Main Line

MALFUNCTION REFERENCE CHART

Branch Line

MALFUNCTION REFERENCE CHART

Short Circuit

MALFUNCTION REFERENCE CHART