U3506Control Module Input Power B Circuit High
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3506 reports overvoltage on supply input B. In GM's electric brake booster (2016–2019 hybrid OBD tables) three checks feed this code: battery voltage of the booster circuit above 17 V for 90 s, the supply of the internal motor driver above 18 V for 1.1 s, and battery voltage above 16.5 V for 1.1 s, at which booster performance is cut back. All are Type B, MIL after two trips; passing takes 90 s with ignition on. The graded limits reveal the idea: brief excursions are tolerated, lasting ones or those that put the power stage at risk are not. Check the charging voltage at idle with loads switched on first, then external chargers, jump starters and loose battery terminals that produce voltage spikes.
- What you may notice
- MIL after two trips
- Reduced assist of the supplied power stage
- Overvoltage codes in further modules
- Likely causes
- LikelyCharging voltage too high from regulator or DC/DC converter
- PossibleJump starter or charger delivering excessive voltage
- PossibleLoose battery terminal causing spikes
- RareFaulty measurement of feed B in the module
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.