U3019Control Module Input Power Circuit B/C Correlation
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3019 pairs the second and third supply of a module and reports that they drift apart. The one published use comes from GM's electric brake booster module in the 2016 and 2018 hybrid tables (16OBDG02, 18OBDG01). There, one voltage sensor watches the booster circuit supply and a second one the supply of the motor driver; the module divides the two readings and sets U3019 when the ratio rises above 1.321 or falls below 0.766 for 2 s while running or shutting down. GM describes this as a check for drift of the voltage divider, so besides a weak feed a measuring fault inside the module is a real candidate. The code is Type A, meaning MIL on the first trip, and it passes after about 5 s with ignition on. Because the booster supports braking, expect a brake warning and possibly reduced assist.
- What you may notice
- MIL and brake system warning on the first trip
- Reduced or harder brake pedal assist
- Often stored with input power low or high codes of the same module
- Likely causes
- PossibleVoltage loss on one feed from a corroded fuse, terminal or splice
- PossibleDrift of the voltage divider or sensor inside the module
- RareMotor driver supply sagging under load from a faulty booster motor stage
- Repair
- Hard · Usually a job for a workshop.Typical cost: €20 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.