P1793
DTC P1793
Circuit Description
The engine control module (ECM) sends wheel speed data to the transmission control module (TCM). The data is sent to the TCM through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P1793 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P1793.
When the TCM receives invalid wheel speed data from the ECM, then DTC P1793 will set. DTC P1793 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1793 Wheel Speed Signal
Conditions for Running the DTC
* The engine run time is at least 6 seconds.
* No other CAN errors are present.
Conditions for Setting the DTC
The TCM receives no valid wheel speed data from the ECM for 2 seconds.
Action Taken When the DTC Sets
* The TCM does not request the ECM to illuminate the malfunction indicator lamp (MIL).
* The TCM inhibits Autograde braking.
* The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
* The TCM stores DTC P1793 in TCM history.
Conditions for Clearing the DTC
* A scan tool can clear the DTC.
* The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
* The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.
