DTC U1500-U15BF
Refer to
Control Module U Code List
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Circuit/System Description
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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 code for non-communication. Note: a DTC on lost serial communication does not mean there is a fault on the master control module that set it.
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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.
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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.
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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.
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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.
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Communication disturbances may temporarily occur due to corrosion on the serial data circuit pin. Inspect all connectors of the control module that generated the DTC and other cable connections between the two control modules. Do not replace a control module due to corrosion alone. Refer to bulletin 09-06-03-004 for diagnostic help and remedies for this condition.
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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
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Note
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Use the schematic to identify the following:
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Control modules and LIN devices the vehicle is equipped with
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LIN unit's B+, ignition, ground and serial data circuit connections
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•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
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•A loss of serial data communications DTC does not represent a failure of the master control module that set it.
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1.
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Ignition OFF, disconnect the harness connector at a LIN device that is not communicating.
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2.
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Test for less than 10 Ω between each ground circuit terminal and ground.
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3.
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If greater than the specified range, test the ground circuit for an open/high resistance.
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4.
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If equipped, verify that a test lamp illuminates between each B+ circuit terminal and ground.
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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.
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6.
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If equipped, ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.
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7.
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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.
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Ignition ON, test for 2-11.5 V between the LIN serial data circuit and ground.
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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.
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10.
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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.
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11.
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If all circuits test normal, replace the LIN device.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
