P1647 - FAULT CODE - OBD2

P1647 Code failures by brands

P1647 LEXUS, TOYOTA: TRANSMISSION CONTROL MODULE SYSTEM MALFUNCTION

Description of DTC code P1647

The TCM (Transmission Control Module) is a controller installed in modern vehicles, which employs an electronic mechanism to collect data and process signals within the transmission, in order to regulate transmission shifting. This control module works closely with different components that depend on its functions, such as the engine, sensors, and switches. Without the mechanism employed by the TCM, transmission shifting cannot be performed correctly and consistently, which would directly affect other components of the car.

The P1647 OBDII fault code is set on Toyota and Lexus vehicles due to a malfunction of the Transmission Control Module system.

Symptoms of fault code P1647

Check Engine lamp illuminated.
Problems when shifting gears.
Transmission enters a failsafe mode.

Causes of OBD2 P1647

P1647 OBD2 diagnostic code is set for one of the following reasons:

TCM wires may have been damaged.
Transmission Control Module connections may be faulty causing the malfunction.
Transmission Control Module could be in poor condition

Possible solutions of the DTC code P1647

The steps to follow to correct the DTC P1647 OBDII code are:

Consult the Technical Service Bulletins.
Employing an automotive scanner, it is necessary to check if additional DTCs to P1647 are configured, especially those that indicate specific faults of the transmission. If such codes are found, repair them.
Inspect all wiring in the Transmission Control Module for damage caused by burns, chafing, or corrosion. Also, check the controller connections for common deficiencies. Repair as required.
If you do not detect damage to the TCM connections and there are no other error codes set, the TCM is likely damaged. However, before performing a repair or replacement, we recommend that you visit an advanced automotive center due to the complexity of the code.