P1890

DTC P1890









Circuit Description with 4L30-E Automatic Transmission
Throttle position information is sent to the Transmission Control Module (TCM) by the Engine Control Module (ECM) 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 P1890 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P1890.
When the ECM sends the TCM throttle position information that is unreliable, DTC P1890 will set. DTC P1890is a type B DTC.

Condition for Running the DTC
The ignition is ON.

Condition for Setting the DTC
The throttle position value is unreliable for 1 second.

Action Taken When the DTC Sets
^ The TCM flashes the sport mode lamp and sends a MIL request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.
^ The ECM records the operating conditions in the Freeze Frame at the time of the MIL request from the TCM.
^ The transmission operates in the default mode (maximum line pressure, command 4th gear, inhibit TCC, freeze shift adapts).

Conditions for Clearing the MIL/DTC
^ The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL request.
^ A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.
^ The TCM cancels the DTC default mode actions when the ignition switch is Off long enough in order to power down the TCM.