OBD-II code P2781 indicates the powertrain control module detects a voltage signal from the manual downshift switch circuit that is higher than expected. This condition typically suggests an open circuit, short to power, or high resistance within the switch assembly or wiring harness. Manual shifting functions are usually disabled while this code is active.
Internal failure within the switch mechanism often creates an open circuit or high resistance.
Wires in the switch circuit may be broken, frayed, or shorted to voltage sources.
Corrosion, bent pins, or loose fits at the switch connector can interrupt signal flow.
If the switch circuit relies on a dedicated fuse, a blowout will prevent proper voltage reading.
Internal failure of the TCM or PCM is possible but statistically rare compared to wiring or switch faults.
It affects manual shifting control but usually does not prevent the vehicle from driving in automatic mode.
No, PCM or TCM failure is rare for this code; the switch or wiring is the usual cause.
Yes, but manual shifting features will be disabled and fuel economy may suffer.
An open circuit, broken wire, or disconnected plug typically causes a high voltage reading.