DTC U1500-U15BF
Diagnostic Instructions
DTC Descriptor
Refer to
Control Module U Code List .
Circuit/System Description
The serial data is transmitted over a Local Interconnect Network
(LIN) single wire network circuit bus between a master control
module and other control modules within a particular subsystem. If
serial data communication is lost between any of the control
modules on the LIN bus network, a no communication code against the
non-communicating control module will be set. A master control
module is the one that reports the non communication code. Note: a
loss of serial data communications DTC does not represent a failure
of the master control module that set it.
Diagnostic Aids
• |
A control module may have a
U-code stored in history that does not require any repairs. Issues
with late or corrupted messages between control modules can be
temporary with no apparent symptom or complaint; this does not mean
the control module is faulty. Do not replace a control module based
only on a history U-code. |
• |
Do not replace a control
module reporting a U-code. The U-code identifies which control
module needs to be diagnosed for a communication issue.
|
• |
Communication will be
available between the master control module and the scan tool if
there is a loss of communications with any of the other control
modules on the LIN bus network. |
• |
An open in the LIN bus serial
data circuit between the splice pack and a module will only affect
that specific module. This type of failure will set a loss of
communication DTC for each control module affected and the other
control modules will still communicate. |
• |
Some intermittent
communication concerns may be caused by fretting corrosion on the
serial data circuit terminals. Inspect all connectors at the
control module that set the communication DTC, the control module
that the communication DTC was set against, and any inline harness
connectors between the two control modules. Do not replace a
control module based only on fretting corrosion. Refer to bulletin
09-06-03-004 for assistance with the diagnosis and repair of this
condition.. |
Reference Information
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
Circuit/System Testing
Note:
• |
Use the schematic
to identify the following: |
|
- |
LIN devices the
vehicle are equipped with |
|
- |
The LIN device's
B+, ignition, ground, and serial data circuit terminals
|
• |
Use the Control
Module U-Code list to determine which control module is not
communicating with the master control module. Refer to
Control Module U Code List . |
• |
A loss of serial
data communications DTC does not represent a failure of the master
control module that set it. |
1. |
Ignition OFF, disconnect the
harness connector at a LIN device that is not communicating.
|
2. |
Test for less than 10 Ω
between each ground circuit terminal and ground. |
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
3. |
If equipped, verify that a
test lamp illuminates between each B+ circuit terminal and
ground. |
⇒ |
If the test lamp does not illuminate, test the B+
circuit for a short to ground or an open/high resistance. If the
circuit fuse is open, test the control circuits of the LIN device
for a short to ground. If the circuits test normal, replace the LIN
device. |
4. |
If equipped, ignition ON,
verify that a test lamp illuminates between each ignition circuit
terminal and ground. |
⇒ |
If the test lamp does not illuminate, test the
ignition circuit for a short to ground or an open/high resistance.
If the circuit fuse is open, test the control circuits of the LIN
device for a short to ground. If the circuits test normal, replace
the LIN device. |
5. |
Ignition ON, test for 2-12 V
between the LIN serial data circuit and ground. |
⇒ |
If greater than the specified range, test the LIN
serial data circuit for a short to voltage. If the circuit tests
normal, replace the master control module. |
⇒ |
If less than the specified range, test the LIN
serial data circuit for a short to ground or an open/high
resistance. If the circuit tests normal, replace the master control
module. |
6. |
If all circuits test normal,
replace the LIN device. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|