P1800

DTC P1800









Circuit Description with 4L30-E Automatic Transmission
The Transmission Control Module (TCM) provides voltage to the pressure control solenoid, the shift solenoids, the band apply solenoid, and the TCC solenoid through an internal power control relay. A normal function of the TCM is to run tests on the power control relay to ensure that it is functioning properly. The power control relay has two output terminals on the TCM. The pressure control solenoid signal circuit receives voltage from TCM terminal 52. The other solenoids receive voltage from TCM terminal 53. TCM terminals 52 and 53 are connected inside the TCM.
When the TCM detects a continuous open circuit at TCM terminals 52 and 53, then DTC P1800 sets. DTC P1800 is a type B DTC.

Conditions for Running the DTC
^ The ignition is ON.
^ No 1-2/3-4 Shift Solenoid valve DTC P0753.
^ No 1-2/3-4 Shift Solenoid valve DTC P0758.
^ No TCC enable solenoid circuit- Electrical DTC P0743.
^ No band apply solenoid circuit DTC P1850.

Condition for Setting the DTC
The TCM detects a continuous open circuit at TCM terminals 52 and 53 for 0.12 seconds

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.

Test Description
The number below refers to the step number on the Diagnostic Table.
6. This test determines if the transmission power relay output circuit is open between the TCM and the splice. For this DTC to set from an open circuit, the open would have to be between the TCM and the splice. An open in either of the circuits after the splice would set DTCs for the affected solenoids only.