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P260CPTO Control Circuit High

Voltage on the power take-off (PTO) control circuit is higher than the control module expects, indicating a short to voltage or an open circuit with the driver commanded on.

Definition

On trucks and chassis equipped with a PTO provision, the PCM/TCM controls or monitors a PTO enable/control circuit that engages the PTO unit and coordinates elevated idle and transmission behavior. P260C sets when the module measures circuit voltage above the expected range, typically from a short to battery voltage or a failed control device. Symptoms range from none at all (if the PTO is unused) to the PTO failing to engage or disengage; the MIL may illuminate. Because this wiring often runs through the upfitter/body-builder harness, aftermarket equipment wiring is a frequent culprit.

Common causes

  • PTO or upfitter wiring shorted to battery voltage (chafed harness, pinched wire)
  • Incorrect aftermarket/upfitter equipment wiring on the PTO control circuit
  • Failed PTO engagement relay or solenoid
  • Corroded or back-fed terminal at the PTO/upfitter connector
  • Faulty PCM/TCM output driver (rare)

Common misdiagnoses

  • PTO unit or hydraulic pump replaced for a wiring fault
  • Transmission solenoids or valve body
  • PCM replaced when upfitter wiring was back-feeding the circuit
  • PTO dash switch replaced without testing the circuit

Troubleshooting steps

  1. 1.Confirm the PTO configuration

    Verify whether the vehicle actually has PTO equipment installed and check that the module's PTO programming matches, since unused upfitter circuits with damage can still set this code.

  2. 2.Inspect the upfitter/PTO harness

    Trace the PTO control wiring, especially aftermarket splices and the upfitter connector, looking for chafes, pinches, and taps into switched battery feeds.

  3. 3.Measure circuit voltage in both states

    With a meter on the PTO control circuit, compare voltage with the output commanded on and off; voltage that stays at battery level regardless of command indicates a short to voltage or open driver load.

  4. 4.Test the PTO relay or solenoid

    Check the coil resistance against spec and verify the relay is not welded closed or mis-pinned in its socket.

  5. 5.Wiggle-test and re-verify

    Flex the harness while watching the circuit status on a scan tool, repair any faults found, clear the code, and confirm it does not reset after a PTO engagement cycle.

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