U0105

DTC U0100-U0299 (Diesel Engine)

Circuit Description
Modules connected to the controller area network (CAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module. A module with a CAN serial data circuits malfunction or which loses power during the current ignition cycle will have a Loss of Communication DTC set by other modules that depend on information from that failed module. If any of the CAN circuits are shorted to battery voltage, ground or between them, no communication is possible on CAN serial data bus, and a DTC U0073 is set.

DTC Descriptors
This diagnostic procedure supports the following DTCs:
^ DTC U0100 Lost Communication With Engine Control Module (ECM)
^ DTC U0101 Lost Communication With Transmission Control Module (TCM)
^ DTC U0105 Lost Communication With Fuel Injector Control Module (FICM)
^ DTC U0106 Lost Communication With Glow Plug Control Module (GPCM)

Conditions for Running the DTCs
^ Voltage supplied to the modules is in the normal operating voltage range.
^ The engine is running.

Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTC Sets
^ The module uses a default value for the missing parameter.
^ The malfunction indicator lamp (MIL) will illuminate on the second consecutive ignition cycle that the diagnostic runs and fails, for the type B DTCs. For a detailed description about DTC types, refer to Diagnostic Trouble Code (DTC) Type Definitions.

Conditions for Clearing the MIL/DTC
The MIL/DTC clearing depends on DTC type. For information about DTC types, refer to Diagnostic Trouble Code (DTC) Type(s).
DTC type B
^ The MIL clears after 3 ignition cycles when the malfunction is no longer present.
^ A current DTC clears when the malfunction is no longer present.
^ A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
DTC type C
^ A current DTC clears when the malfunction is no longer present.
^ A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids
^ A poor connection at the inoperative module may cause this code to set.
^ An improperly powered module may cause this code to set.

Steps 1 - 5:

Steps 6 - 10:

Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. A total loss of communication on CAN serial data link should be diagnosed first.
10. The modules which can communicate indicate the module which cannot communicate. You must clear the DTC from these modules to avoid future misdiagnosis.