P2782 indicates that the powertrain control module (PCM) has detected an intermittent or erratic signal from the downshift switch circuit. This switch, often part of the kickdown system, signals the transmission to downshift when the accelerator pedal is fully depressed.
The switch itself may be worn, stuck, or internally shorted, causing an intermittent signal.
Chafed, broken, or corroded wires in the downshift switch circuit can create intermittent opens or shorts.
A loose or corroded ground for the switch or PCM can cause erratic voltage readings.
On some vehicles, the downshift function is integrated with the TPS; a failing TPS can mimic a downshift switch fault.
Rarely, a software issue or internal fault in the control module can cause false intermittent codes, but this is uncommon.
The downshift switch (also called a kickdown switch) signals the transmission to downshift when the accelerator pedal is pressed past a certain point, usually for passing or hard acceleration.
Yes, but you may experience poor acceleration and shifting. The transmission may not downshift properly, which can be a safety concern when merging or passing. It's best to diagnose and repair promptly.
No. The PCM is rarely the cause. Most often the issue is a faulty switch, damaged wiring, or a poor connection. Replacing the PCM should only be considered after thoroughly testing all other components.