U350B code meaning
Control Module Input Power C Circuit Intermittent/Erratic
What U350B means
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.
U350B at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U350B
- Brief loss of assist from the motor-driven function
- Sporadic warning lamp that clears again
Common causes of U350B
- Most likelyLoose fuse contact or ring terminal in feed C or its ground
- PossibleChafed wire near the module
- PossibleCorroded connector pins
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Module power cPower wiring
What each part of U350B means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 0B | The exact fault in that area. |
What to do next
- Note U350B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U350B
What does U350B mean?
U350B means "Control Module Input Power C Circuit Intermittent/Erratic". U350B reports that supply C fluctuates: it drops or spikes briefly without staying out of range. It is a generic code, so it means the same on every make.
Is it safe to drive with U350B?
Drive gently and only to a workshop. With U350B the car can go into limp mode (reduced power) to protect itself.
Will U350B fail an emissions test?
U350B is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U350B to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U350B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.