P2778
Upshift Switch Circuit Intermittent/Erratic
Transmission (manual-shift mode)
Generic OBD-II
Low
What it means
P2778 means the transmission controller is seeing an unstable or erratic signal from the manual upshift (tap-up) switch used by AutoStick / Tiptronic-style shifting. It's usually a wiring or switch-contact problem. Automatic shifting is unaffected, so the main impact is that manual upshift requests may be ignored or act on their own.
Low
Can I keep driving? Yes — the car drives and shifts normally in automatic mode; you may just lose the manual tap-up (AutoStick) function until it's fixed.
Common symptoms
What you'll notice
- Manual (tap) upshift requests are ignored or intermittent
- Transmission occasionally shifts on its own in manual mode
- Check-engine light on with the code stored
- AutoStick / manual mode feels unresponsive
Common causes
Most likely first
- Worn, dirty, or sticking upshift switch contacts on the shifter or paddleLikely
- Chafed, loose, or corroded wiring/connector at the shift switchCommon
- Moisture or liquid intrusion into the shifter switch assemblyCommon
- Faulty shifter/paddle switch assemblyLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame and wiggle-test the shifter/paddle wiring while watching the switch signal.
- Inspect the switch connector for corrosion, spread pins, or moisture; clean and reseat.
- Operate the upshift switch and check for a clean on/off signal with a scan tool or meter.
- Replace the shifter/paddle switch assembly if the contacts are worn or erratic, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2778?+
Yes. Automatic shifting still works normally — you may only lose the manual upshift feature, so it's not a safety or damage risk.
Can I just clear P2778?+
You can, but if the switch or wiring is intermittent the code will return the next time the fault appears. Fix the switch/wiring for a lasting clear.
Related codes
Often seen with P2778
Read & clear P2778 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