NTB10066A

Classification:
Reference:
El10-017a
Date:
NTB10-066a
June 24, 2014
CAN COMMUNICATION CODES – DIAGNOSTIC TIPS &
GUIDELINES
This bulletin has been amended to include information on the use of
DLC Breakout Box tool J-51513. Please discard previous version.
APPLIED VEHICLES:
All 2005–2015 Nissan vehicles
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 mis-diagnosis.
Step 2
View the V-CAN screen (shown on page 3) or print all CAN Diag Support Monitors
(shown on page 4).
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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.
Step 4
If V-CAN diagnosis is not available or inconclusive, refer to the basic CAN diagnostic
guidelines shown on pages 5-12. 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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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
CONSULT-III again. If module is still highlighted in pink, replace module.
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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.
4/13
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”
shows in Figure 1 below.

Do Not connect the C-III plus 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” pinout to either of the ground pin-outs.
Damage will occur.

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.
Front of DLC Breakout Box
Figure 1
DLC legend
Back of DLC Breakout Box
Figure 2

Figure 3 show 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
5/13
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
#14 CAN 2* Low
6
Data Link
Connector
>1 KΩ
14
#6 CAN High
Plug “DLC Breakout
Box” J-51513 into DLC
6/13
#13 CAN 2* High
* Certain models are equipped
with 2 CAN systems
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
If measured with
terminating module
disconnected,
Resistance = 120 Ω
6
#14 CAN Low
60 Ω
Data Link
Connector
14
7/13
#6 CAN High
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
8/13
#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
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
Notes:
#6 CAN High
• OL= Open Circuit
• Expect OL if battery negative cable is connected
• Expect 1.0KΩ – 1.2KΩ if battery negative cable is disconnected
14
9/13
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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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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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
12/13
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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