ITB10-029B

Classification:
Reference:
Date:
EL10-018B
ITB10-029B
January 26, 2022
CAN COMMUNICATION CODES – DIAGNOSTIC TIPS AND GUIDELINES
This bulletin has been amended. See AMENDMENT HISTORY on the last page.
Please discard previous versions of this bulletin.
APPLIED VEHICLES:
All 2005-2022 Infiniti vehicles except:
 2022 QX60 (L51)
SERVICE INFORMATION
Related to communication codes U1000, U1001, U1002, U1010:

Always diagnose the communication codes first.

When a module reports a U1000 code, it is typically operating normally; however, there is a
communication error external to that module on the CAN network.

U1000 indicates an error. V-CAN diagram or CAN Diag Support Monitor provides data to
determine the location of the error.
Step 1
Complete the CAN diagnosis with CONSULT-III plus (C-III plus).

Ensure the correct CAN type is selected. Selecting the incorrect CAN type will lead to misdiagnosis.
Step 2
View the V-CAN screen (shown on page 3) or print all CAN Diag Support Monitors (shown on page 4).
Step 3
Read the V-CAN diagram using the key provided OR reference the appropriate Electronic Service
Manual (ESM) to analyze the CAN Diag Support Monitor data. Determine the incident according to the
display.
Infiniti Bulletins are intended for use by qualified technicians, not 'do-it-yourselfers'. Qualified technicians are properly trained
individuals who have the equipment, tools, safety instruction, and know-how to do a job properly and safely. NOTE: If you
believe that a described condition may apply to a particular vehicle, DO NOT assume that it does. See your Infiniti retailer to
determine if this applies to your vehicle.
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Step 4
If V-CAN diagnosis is not available or inconclusive, refer to the basic CAN diagnostic guidelines shown
on pages 6-13. These represent electrical values of the CAN system measured at the Data Link
Connector or connectors at non-termination units.
To properly perform these basic checks:

The battery should be disconnected for resistance checks.

The ignition should be OFF.
Tips if a control module is the suspected root cause:

Improper module configuration or incorrect part numbers may set CAN DTCs.

Low battery voltage may set CAN DTCs.

Always confirm the power, ground, and CAN resistance at a suspect module before replacing
the module. Resistance should be close to 60 ohms at the module (measured with the battery
disconnected). The resistance at terminating modules should be close to 120 ohms. Examples of
terminating modules include IPDM, ECM, or BCM. Reference the appropriate ESM to determine
the terminating modules.
DEFINITION OF CAN CODES
U1000 is related to missing CAN communications on the network.
U1001 is for Engine Control Module (ECM) and is related to missing CAN communications on the
network.
U1002 is related to missing CAN communications on the network but has a tighter spec than U1000.
U1010 - Module has internal errors.
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ITB10-029B
V-CAN Diagram Screen
Step 3 Illustration
TCM
Red = Current Communication Error
Orange = Past or Intermittent Communication Error
Black = Not Diagnosed
Green = Normal Operation
Pink = Module Error
NOTE: If module is highlighted in pink when other modules or segments are highlighted in red or orange, perform diagnosis on other modules,
erase DTCs, and run Auto CAN diagnosis with C-III plus again. If module is still highlighted in pink, replace module.
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ITB10-029B
CAN Diag Support Monitor
Step 3 Illustration
Print Example
NOTE:
These prints are needed for ESM CAN
Diagnosis or if the V-CAN diagram
diagnosis is not available.
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ITB10-029B
DLC Breakout Box J-51513
When performing any pin testing of the CAN systems
at the DLC (Data Link Connector), “DLC Breakout
Box” J-51513 should be used.

Plug the DLC Breakout Box into the vehicle
DLC connector and perform all voltage,
resistance and continuity testing directly from
the provided “pin-outs” shown in Figure 1.

Do not connect the CONSULT PC to this tool.
Although it does have a port to do so, the tool
currently does not support this function.

Do not jumper the “Battery Power” pin-out to
either of the ground pin-outs.
Front of DLC Breakout Box
Figure 1
Damage will occur.
DLC legend

All pin-out locations are marked in
accordance with their associated DLC
connections and will allow convenient pin
testing of the DLC connector.

Figure 2 shows the back of the DLC Breakout
Box, and has a legend of the DLC pins.
Back of DLC Breakout Box
Figure 2

Figure 3 shows Banana leads that are
supplied with the DLC Breakout Box and are
used to connect to a DVOM.
NOTE: 48” Banana Leads
(J-35616-20W) are available and are sold
separately.
Banana test leads
Figure 3
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Battery is Possibly
Connected - disconnect and
recheck resistance
120Ω
120Ω
#14 CAN Low
6
#14 CAN 2* Low
Data Link
Connector
>1 KΩ
14
#6 CAN High
Plug “DLC Breakout Box”
J-51513 into DLC
6/14
#13 CAN 2* High
* Certain models are equipped with 2
CAN systems
ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Normal Resistance –
CAN Harness
120Ω
120Ω
120Ω
120Ω
If measured with
terminating module
disconnected,
Resistance = 120 Ω
6
#14 CAN Low
60 Ω
Data Link
Connector
14
#6 CAN High
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Normal Resistance –
CAN High to Ground
120Ω
120Ω
120Ω
120Ω
120Ω
#14 CAN Low
6
4
Data Link
Connector
1K Ω -OL
#6 CAN High
Notes:
• OL= Open Circuit
• Expect OL if battery negative cable is connected
• Expect 1.0KΩ – 1.2KΩ if battery negative cable is disconnected
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Normal Resistance –
CAN Low to Ground
120Ω
120Ω
#14 CAN Low
4
Data Link
Connector
1K Ω -OL
#6 CAN High
14
Notes:
• OL= Open Circuit
• Expect OL if battery negative cable is connected
• Expect 1.0KΩ – 1.2KΩ if battery negative cable is disconnected
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Open CAN Harness
120Ω
120Ω
#14 CAN Low
6
Data Link
Connector
120 Ω
14
#6 CAN High
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Short – CAN High to
CAN Low
120Ω
120Ω
#14 CAN Low
6
Data Link
Connector
<1 Ω
14
#6 CAN High
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Normal Voltage –
CAN High
120Ω
120Ω
6
#14 CAN Low
4
Data Link
Connector
2.5-3.5 V
#6 CAN High
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ITB10-029B
NOTE: Diagram shown with terminal resistor in IPDM. The vehicle that you are working on may have the
terminal resistor in the BCM. Refer to the ESM for additional information.
Normal Voltage –
CAN Low
120Ω
120Ω
#14 CAN Low
4
Data Link
Connector
1.5-2.5 V
14
#6 CAN High
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ITB10-029B
AMENDMENT HISTORY
PUBLISHED DATE
REFERENCE
DESCRIPTION
May 7, 2010
ITB10-029
Original bulletin published
June 24, 2014
ITB10-029A
Information added regarding the use of DLC Breakout Box
tool J-51513
January 26, 2022
ITB10-029B
APPLIED VEHICLES revised
14/14
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ITB10-029B