U3508 code meaning
Control Module Input Power C Circuit Range/Performance
What U3508 means
U3508 checks the plausibility of a third supply input, C. Only modules with large or separately protected loads have three feeds; in GM's electric brake booster (2016–2019 hybrid tables) C is the motor driver feed, measured by voltage sensor 2 and compared with feed B through U3019 (ratio outside 0.766 to 1.321). U3508 would apply if C is present but its value does not suit the operating state, for instance staying high while the motor draws current or departing from battery voltage, without crossing a hard limit. No manufacturer documents U3508 publicly; GM uses only the Low and High codes for C. Check the motor feed and its ground under load and look for related U3019 or U3013.
U3508 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U3508
- Reduced function of the motor-driven system
- Correlation codes between feeds stored as well
Common causes of U3508
- PossibleResistance in the motor supply path of feed C
- PossiblePoor ground of the power stage
- Less likelyDrift of the internal voltage divider
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 U3508 means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 08 | The exact fault in that area. |
What to do next
- Note U3508 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 U3508
What does U3508 mean?
U3508 means "Control Module Input Power C Circuit Range/Performance". U3508 checks the plausibility of a third supply input, C. It is a generic code, so it means the same on every make.
Is it safe to drive with U3508?
Drive gently and only to a workshop. With U3508 the car can go into limp mode (reduced power) to protect itself.
Will U3508 fail an emissions test?
U3508 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 U3508 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U3508 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.