INFINITI QX56 2008 Factory Service Manual

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DIAGNOSIS AND REPAIR WORKFLOW
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 the figure below).
4. Through the above procedure, the error is detected in the TCM branch line (shaded in the figure below). NOTE:
For abbreviations, refer to LAN-36, "
Abbreviation List".
PKID1218E
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5. Perform the inspection for the detected error circui
t. For the inspection procedure, refer to “MALFUNC-
TION AREA CHART”.
Present Error — Short Circuit —
When the symptoms listed below exist, a short circui t of the CAN communication line is a possible cause.
Received data
Error symptom• Most the units connected to the CAN communication system go into fail-safe mode or are deactivated.
Inspection procedure
PKID1219E
Item (CONSULT-III) Indication
ECU list (on the CAN DIAG SUPPORT MNTR) A ll Diag on CAN units are not indicated.
CAN DIAG SUPPORT MNTR “UNKWN” is indicated under “TRANSMIT DIAG” and most reception items.
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DIAGNOSIS AND REPAIR WORKFLOW
• Refer to “MALFUNCTION AREA CHART”.
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.
PKID1220E
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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 LAN-47, "
CAN Diagnostic Sup-
port Monitor".
a. 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).
b. 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).
PKID1221E
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DIAGNOSIS AND REPAIR WORKFLOW
c. 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 the figure below).
3. CAN DIAG SUPPORT MNTR (without PAST): Chec k 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 indi-
cate the possible error circuit.
NOTE:
• While an error occurred in the past according to SE LF-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 it ems. (Work flow differs from CAN DIAG SUPPORT
MNTR (with PAST).)
a. 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 the figure below).
PKID1222E
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b. 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 the figure below).
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 LAN-44, "
CAN Communication Signal Chart".
a. 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 the figure below).
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DIAGNOSIS AND REPAIR WORKFLOW
b. The tachometer moved normally: This means that “Engine speed signal” could communicate normally
between ECM and M&A (4-b in the figure below).
5. Fill out the diagnosis sheet based on information from step 4.
a. 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 the figure
below).
SKIB8895E
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b. 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 the figure below).
6. The circuit which has the most amount of lines are the possible cause. Error is detected from ABS actua- tor and electric unit (control unit) branch line (shaded in the figure below).
NOTE:
For abbreviations, refer to LAN-36, "
Abbreviation List".
SKIB8735E
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DIAGNOSIS AND REPAIR WORKFLOW
7. Perform the inspection procedure for the possi
ble cause. Refer to “MALFUNCTION AREA CHART”.
Past Error — Short Circuit —
When the symptoms listed below exist, a short circuit of the CAN communication line is a possible cause.
PKID1224E
Item (CONSULT-III) IndicationInspection procedure
SELF-DIAG RESULTS “U1000” and “U1001” is indicated in the past for most units. Refer to “MALFUNCTION AREA
CHART”.
CAN DIAG SUPPORT MNTR Only on CAN DIAG SUPPORT MNTR (with PAST), “1 - 39” is in-
dicated on “PAST” of “TRANSMIT DIAG” and the reception item.
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PKID1225E
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2008 QX56