U301CControl Module Wake-up Circuit A High
- Generic OBD-II code · Network
- How the car detects it
- U301C is the opposite of U301B: wake-up line A is stuck high, usually shorted to a battery-fed wire or held up by a sender that never releases it. The receiving module then gets a permanent wake request. In Ford's 2019 hybrid OBD summary, a high charge wake-up signal is one of the conditions under which the battery energy control module runs its charge contactor and pack contactor checks, so a line stuck high makes the module behave as if charging were requested. The likely result is a module that never falls asleep and a 12 V battery that is flat after a few days of parking. A transceiver like NXP's TJA1043 also needs a change of level to register a wake, so a permanently high line cannot deliver a fresh wake event either. No manufacturer documents U301C publicly.
- What you may notice
- 12 V battery drained after the vehicle has been parked
- Module or fan audible or active with the vehicle switched off
- Likely causes
- LikelyWake-up wire shorted to a battery or ignition feed
- PossibleSending module or charger holding the wake output on
- RareMoisture bridging the wake pin to a neighbouring supply pin
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.