U3029Control Module A Disable Feedback Circuit Low
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U3029 narrows the feedback fault to a signal that stays below its valid range, typically a readback wire shorted to ground. The consequence follows from the readback idea in GM's patent US9122662B2, where the inhibit path is driven through known test states and its actual output compared with the expected one: if the feedback is pinned low, every state that should read high fails, and the monitor cannot tell a working shutdown from a broken one. Depending on the design, a permanently low readback may also be taken as module A already being disabled. No manufacturer documents U3029 publicly. The usual suspects are a chafed readback wire touching the body, water in a connector or a defective input stage; the disable line itself should be checked separately.
- What you may notice
- Function of module A locked out, system warning displayed
- Code returns at every start until the short is found
- Likely causes
- LikelyFeedback wire shorted to body ground
- PossibleMoisture or corrosion pulling the readback pin low
- RareDefective readback input stage in the monitoring module
- Repair
- Hard · Usually a job for a workshop.Typical cost: €50 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.