What it means
The second PTO speed-selector switch input is open. Switch 2 typically encodes a binary or multi-bit code together with switch 1 — together they select one of several preset PTO speeds. With switch 2 broken, only the half of the bit pattern is available, so several presets cannot be reached.
At a glance
- Usually lights the check-engine light
How it works
The second PTO speed-selector switch input supplies one part of the selection pattern used to choose a preset power take-off speed. The control module monitors switch 2 for an open circuit and sets P255A when that input is missing, which can leave some selector combinations unavailable or misread.
Common causes
Most likely first.
- Open wire or unplugged switch
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check-engine light
- Some PTO speed settings may be unavailable or incorrect
- PTO operation may be limited
How to diagnose it
- Record freeze-frame data and check PTO selector live data, if available, to see which speed pattern is missing when switch 2 is open.
- With the PTO disengaged and the vehicle secured, inspect the switch 2 connector for disconnection, corrosion, or a terminal pushed back into the housing.
- Trace the switch 2 wire for cuts, chafing, or loose connections, paying attention to areas that move with the selector or PTO equipment.
- Operate the selector through its positions while monitoring switch 2 state to check whether the input changes or remains open.
- Use the wiring diagram to test continuity through the switch 2 circuit and selector, following the manufacturer's specification.
Common fixes
- Reconnect a loose or unplugged PTO switch 2 connector.
- Repair an open or damaged switch 2 wire.
- Replace or repair a pushed-back or corroded connector terminal.
- Replace a faulty switch 2 selector input after confirming the wiring is intact.
- Repair a failed internal connection in the selector module if the external circuit tests correctly.
Can I keep driving?
Avoid relying on the PTO speed settings that are unavailable or selected incorrectly, and disengage the PTO if its operation becomes unpredictable. The fault can limit PTO use and may prevent the intended operating speed from being selected.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.