U350BControl Module Input Power C Circuit Intermittent/Erratic
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U350B reports that supply C fluctuates: it drops or spikes briefly without staying out of range. Where C feeds a motor stage, as in GM's electric brake booster (motor driver supply, voltage sensor 2), such faults surface at moments of peak current, because a loose contact then loses voltage or opens for an instant. GM itself uses only the Low, High and correlation codes for this feed, and no manufacturer documents U350B publicly. The difference from U3509 lies in the timing: short events rather than a steady low level. Typical findings are a fuse with weak clamping, a loose ring terminal on the ground, chafing near the module or corroded pins; check with a recording meter while the load is operating and look for U3019 as a companion code.
- What you may notice
- Brief loss of assist from the motor-driven function
- Sporadic warning lamp that clears again
- Likely causes
- LikelyLoose fuse contact or ring terminal in feed C or its ground
- PossibleChafed wire near the module
- PossibleCorroded connector pins
- Repair
- Medium · Often possible to do yourself.Typical cost: €10 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.