P2777
Upshift Switch Circuit High
Transmission
Generic OBD-II
Low
What it means
P2777 means the transmission controller sees an abnormally high voltage on the upshift switch circuit — the input used for driver-requested manual upshifts (paddle shifters or a tap-shift gate). The automatic transmission usually keeps shifting normally; the main effect is that the manual upshift request may not register. It's a low-severity electrical fault, typically a wiring or switch problem.
Low
Can I keep driving? Yes — the transmission still shifts automatically; usually only the manual upshift request (paddle/tap) is affected.
Common symptoms
What you'll notice
- Check-engine light on
- Manual upshift (paddle or tap-shift) doesn't respond
- Transmission stays in automatic mode only
- No change to normal automatic shifting in most cases
Common causes
Most likely first
- Open or high-resistance in the upshift switch signal wireLikely
- Faulty upshift switch (paddle or shifter contact)Common
- Corroded or loose connector at the switch or TCMCommon
- Signal wire shorted to a voltage sourceLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the code is current, not a one-off.
- Inspect the upshift switch connector and wiring for damage, corrosion, or looseness.
- Measure the switch signal voltage while pressing the upshift control and compare to spec.
- Repair the wiring or replace the upshift switch if it reads out of range.
- Clear the code and confirm the manual upshift function works.
FAQ
Quick answers
Is it safe to drive with P2777?+
Generally yes. The automatic transmission keeps working normally; usually only the manual upshift request is lost. Get it fixed at your convenience.
Can I just clear P2777?+
You can, but it returns until the switch or its wiring is repaired.
Related codes
Often seen with P2777
Read & clear P2777 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX