U0103Lost Communication With Gear Shift Control Module A
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U0103 points to gear shift control module A, the electronic selector (lever, rotary knob or buttons) in shift-by-wire cars. GM's 2025 engine controllers talk to it over a LIN line and set the code as Type B once its response is absent for at least 500 ms. Stellantis calls it Electric Gear Shift Module: on the Ram 1500 (case S2208000168) U0103-00 appears with U11E3 and U1267 when the rotary selector will not leave Park, and new ESM software is the cure. Ford's Mach-E TSB 21-2405 stores U0103:87 in a secondary OBD module with a wrench lamp and Shift System Fault, fixed by reprogramming; for Explorer/Aviator, SSM 49329 blames loose grounds G210/G214. U0404 is the invalid-data sibling.
- What you may notice
- Service Shifter or Shift System Fault message
- Selector stuck in Park or gear changes refused
- MIL or wrench lamp on
- Intermittent no-crank
- Likely causes
- LikelySelector module software fault (update available from the maker)
- PossibleLoose ground or blown fuse feeding the selector
- PossibleOpen or shorted LIN/CAN line to the selector
- RareSelector module internally faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.