U0103: Lost communication with the gear shift module
The vehicle network has stopped receiving messages from the gear selector module. Power, ground, a connector or network wiring is usually to blame.
| Code | U0103 |
|---|---|
| System | Communication network |
| Group | U01xx, Lost communication with control units |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What U0103 means
The car’s control units talk to each other over a data network (CAN bus). This code means the module that reads the gear lever position has stopped sending messages. Without that information, the gearbox may not know which gear you have selected.
Most common causes
- Low battery or loose terminals, especially after a jump start or battery change
- Blown fuse for the gear selector module
- Loose, corroded or damp connector on the module
- Poor ground connection to the module
- Damaged or chafed network wiring under the centre console
- Faulty gear selector module
Symptoms
- Engine or gearbox warning light on
- Gearbox ignores the lever or will not leave Park
- Gear indicator on the dashboard blank or flashing
- Gearbox goes into limp mode
Can you drive with U0103?
With care If the gearbox responds normally you can drive, but it may stick in one gear or refuse to leave Park. Get it checked soon.
Open the bonnetthe in-depth explanation
How to check it
Check which other U codes are stored: if several modules have lost communication, the problem is usually power supply or the network rather than this module. Also measure battery voltage with the engine off (around 12.4 V or more).
How to read and clear U0103 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see U0103 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- U0100 Lost communication with engine control module (ECM/PCM A)
- U0101 Lost communication with transmission control module (TCM)
- U0102 Lost communication with transfer case control module
- U0104 Lost communication with the cruise control module
- U0105 The fuel injector control unit is not answering on the car network
- U0106 The glow plug control unit is not answering on the car network
- U0107 Lost communication with the throttle actuator control module
- U0121 Lost communication with the ABS control module
- U0126 Lost communication with the steering angle sensor module
- U0128 Lost communication with the park brake control module
- U0131 Lost communication with the power steering control module
What does code U0103 mean?
The car’s control units talk to each other over a data network (CAN bus). This code means the module that reads the gear lever position has stopped sending messages. Without that information, the gearbox may not know which gear you have selected.
Can you drive with U0103?
If the gearbox responds normally you can drive, but it may stick in one gear or refuse to leave Park. Get it checked soon.
How do you clear U0103?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, U0103 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
