P0790
Normal/Performance Switch Circuit
Transmission
Generic OBD-II
Low
What it means
P0790 means there is an electrical fault in the circuit for the normal/performance (sport) mode switch that tells the transmission how aggressively to shift. The car drives normally; the main effect is that you may be unable to change shift modes. The usual causes are the switch itself or a wiring or connector fault.
Low
Can I keep driving? Fully drivable — the car runs normally; you may just lose the ability to switch between normal and performance (sport) shift modes.
Common symptoms
What you'll notice
- Cannot switch between normal and performance (sport) shift modes
- Transmission stays locked in one shift mode
- Check-engine light on
Common causes
Most likely first
- Faulty normal/performance mode switchLikely
- Damaged wiring or corroded connectors in the switch circuitCommon
- Loose or corroded connector at the switch or TCMCommon
- Failed transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the code with the switch operated through both positions.
- Test the switch for correct signal change between normal and performance positions; replace if it doesn't switch.
- Inspect the switch wiring and connectors for damage or corrosion and repair as needed.
- Verify the TCM is receiving the signal; clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P0790?+
Yes — this is a mode-select switch fault. The transmission still shifts; you may just be stuck in one mode until it is fixed.
Can I just clear P0790?+
You can, but if the switch or its wiring is faulty the code returns the next time the system checks the circuit.
Related codes
Often seen with P0790
Read & clear P0790 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