P1780 - FAULT CODE- OBD2

P1780 FORD, LINCOLN, MAZDA, MERCURY: TRANSMISSION CONTROL SWITCH CIRCUIT IS OUT OF SELF-TEST RANGE

Some Ford and other vehicles that have automatic transmissions, also have a Transmission Control Switch (TCS). The TCS is incorporated into the gear selector. By pressing this switch, it is possible to prevent the transmission from going into overdrive.

The P1780 OBDII fault code is used by Ford, Lincoln, Mazda, and other manufacturers. It indicates that the Powertrain Control Module (PCM) has detected a fault in the TCS/TCSL circuit.

• Check Engine ON.
• TCS light ON.
• Transmission does not enter or does not shift out of overdrive.

Reasons to set the P1780 OBD2 diagnostic code P1780 :

• Transmission Control Switch circuit wires or connectors may be damaged.
• The transmission control indicator lamp may be faulty.
• The TCS may be faulty.
• The Powertrain Control Module (PCM) may be damaged.

Steps to troubleshoot the DTC P1780 OBDII code:

• Consult the Technical Service Bulletins.
• Check all the electrical components related to the Transmission Control Switch, and check them for common damage. Likewise, check the switch for deficiencies. Make any necessary corrections.
• Verify that the power supply circuit and the ground circuit are properly powered. If you discover inconsistent voltages, make the appropriate repairs.
• With the Transmission Control Switch unplugged from its connector, use a multimeter and make sure the resistance is within the proper levels. If the switch is depressed, the meter should read less than 5 ohms, but with the switch released, it should read more than 10 ohms. If the readings are out of these parameters, the switch is faulty and should be replaced.
• The Transmission Control Indicator Lamp gets power from the same source as the TCS. If the switch is working properly, so should the lamp. To check its right performance, unplug its corresponding connector on the PCM, and verify there is no open circuit. If you find such deficiencies, make the right repairs.