U3024Control Module Input Power Circuit B - Ignition Input On/Start Circuit Correlation
- Generic OBD-II code · Network
- How the car detects it
- U3024 is the same plausibility test as U3023, but against the module's second battery feed, B: with the key in run or start, feed B and the switched ignition input should show about the same voltage, and a lasting gap points to a fault on one of the two paths. The code only makes sense on modules with two permanent feeds plus an ignition line. No manufacturer documents U3024 publicly. For guidance, GM's 2025 tables describe the A variant in engine and transmission modules: battery present, run/crank active, starter not engaged, and a difference above 3 V in most of 50 samples. If only U3024 is stored and not U3023, feed B itself is the more likely culprit, since a missing ignition signal would upset both comparisons. Effects depend on what feed B powers inside the module.
- What you may notice
- Warning lamp or message, depending on the module
- Loss of functions supplied through feed B
- Likely causes
- LikelyBlown fuse or damaged wire on battery feed B
- PossibleRun/crank relay or ignition wire delivering too little voltage
- PossibleLoose or corroded pin for feed B in the module connector
- RareFaulty voltage sensing inside the module
- Repair
- Medium · Often possible to do yourself.Typical cost: €10 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.