P2684Actuator Supply Voltage C Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Some transmission controllers power groups of solenoids through several internal high-side outputs; supply C is the third of these rails, after A (P0657) and B (P2669). P2684 reports an open load on it. GM's 2023 and 2024 TCM tables tie the code to high-side output 7 and test it while the module powers down: with the output off and a low-side driver on, the load should drag the line low, so a level above 40 % of battery voltage is remembered as an open load and reported after the next start, Type A. Ford's 2024 summary assigns P2684 to high side driver 7 of the TR9070 dual-clutch gearbox, and Ford's 2014 Boss 302S code list carries it as well. Whatever hangs on that rail stops working, so a default gear or limp mode is likely.
- What you may notice
- Transmission in default gear or limp mode
- MIL on after restart
- Several solenoid circuit codes stored together
- Likely causes
- LikelyBroken wire or loose terminal between the module output and the supplied solenoids
- PossibleCorroded or unseated transmission connector or internal lead frame
- RareHigh-side output inside the controller defective
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.