U3500 code meaning
Control Module Input Power A Circuit Range/Performance
What U3500 means
U3500 says that supply input A of a module is present but its voltage is implausible, for example outside the window expected for the current power mode or contradicting other measurements, without clearly passing a lower or upper limit. It thus sits between U3006, which reports a missing or open feed, and the hard limit codes U3501 and U3502. Which pin is A is up to the manufacturer; in GM's electric brake booster tables (2016–2019 hybrid) A is the module's own logic and CAN supply, watched for under 7.5 V and over 16 V, but GM uses only the Low and High codes there. No manufacturer documents U3500 publicly. Typical causes are a high-resistance contact that sags under load, a poor ground or a drifting internal measurement.
U3500 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U3500
- Functions of the module dropping out or behaving inconsistently
- Code returns mainly under electrical load
Common causes of U3500
- PossibleHigh-resistance terminal or fuse contact on feed A
- PossiblePoor module ground shifting the measured supply
- Less likelyDrifting voltage measurement inside the module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Module power aPower wiring
What each part of U3500 means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 00 | The exact fault in that area. |
What to do next
- Note U3500 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 U3500
What does U3500 mean?
U3500 means "Control Module Input Power A Circuit Range/Performance". U3500 says that supply input A of a module is present but its voltage is implausible, for example outside the window expected for the current power mode or contradicting other measurements, without clearly passing a lower or upper limit. It is a generic code, so it means the same on every make.
Is it safe to drive with U3500?
U3500 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U3500 fail an emissions test?
U3500 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 U3500 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 U3500 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.