U0103 code meaning
Lost Communication With Gear Shift Control Module A
Network system Generic code U01xx codes Check engine light
What U0103 means
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.
U0103 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0103
- Service Shifter or Shift System Fault message
- Selector stuck in Park or gear changes refused
- MIL or wrench lamp on
- Intermittent no-crank
Common causes of U0103
- Most 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
- Less likelySelector module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Gear shift moduleCAN bus wiring
What each part of U0103 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 03 | The exact fault in that area. |
What to do next
- Note U0103 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0103
What does U0103 mean?
U0103 means "Lost Communication With Gear Shift Control Module A". U0103 points to gear shift control module A, the electronic selector (lever, rotary knob or buttons) in shift-by-wire cars. It is a generic code, so it means the same on every make.
Is it safe to drive with U0103?
Drive gently and only to a workshop. With U0103 the car can go into limp mode (reduced power) to protect itself.
Will U0103 fail an emissions test?
Yes, it can. U0103 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0103 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0103 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.