P1790 - FAULT CODE - OBD2

P1790 BUICK, CADILLAC, CHEVROLET, GMC: TRANSMISSION CONTROL MODULE CHECKSUM

The Transmission Control Module (TCM) is responsible for checking the proper operation of the transmission, including the actuators and sensors that provide important information to the transmission

All operating data is sent over the CAN bus (Controller Area Network), a system by which the automotive controllers and microprocessors share information from the devices they control

The P1790 OBDII fault code is a code applied by manufacturers such as Chevrolet, GMC, Cadillac, and others, to indicate that the Transmission Control Module has found discrepancies between the calculated checksum data and the obtained checksum data.

• Check Engine lamp illuminates.

The reasons why the DTC P1790 OBD2 is set are:

• The wiring or connections between the Transmission Control Module and the Engine Control Module may be faulty.
• The ECM may be damaged.
• The TCM may be faulty.

The steps to follow to correct the P1790 OBDII diagnostic code are:

• To start the diagnosis we recommend you consult the TSB.
• Use a scan tool to check if other fault codes are stored. If this is your case, you must repair the codes following the order indicated on the scanner.
• Inspect all electrical connections between the TCM and ECM. Look for deficiencies in the wiring or connectors such as wear, burns, or corrosion. If such inconsistencies are found, make repairs.
• If repairs to the electrical components are completed and the P1790 code is still displayed, suspect a TCM.