U0103 on 2011-2023 RAM 1500 — Lost Communication With Gear Shift Control Module "A"
1 vehicles · 1 makes · $300-$900 repair
How to diagnose and fix U0103: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
RAM 1500 · 2011–2023
4WD-equipped Ram 1500 trucks use an electric shift motor (encoder/gear motor) bolted to the BorgWarner transfer case to move between 2WD, 4WD-Auto, 4-High and 4-Low. The motor's internal plastic gears wear or strip, and water/road-salt intrusion corrodes the connector and motor windings, so the system fails to complete a shift. The dash shows 'Service 4WD,' the mode indicator blinks without engaging, and grinding or clicking can be heard from under the truck. A large share of Ram 4WD-engagement complaints trace to the shift motor rather than internal transfer-case damage, so it is usually a relatively affordable fix if caught early. FCA TSB 08-094-20 provides a Drivetrain Control Module (DTCM) software update for 2016-2020 trucks with this symptom.
Common Symptoms
- 'Service 4WD' warning message
- 4WD will not engage or disengage
- Mode indicator blinks but never locks in
- Grinding or clicking under the truck when shifting modes
- Stuck in 2WD or stuck in 4WD
How to Fix
Scan for transfer-case/DTCM codes and check the connector for corrosion first. Apply the DTCM software update (TSB 08-094-20) if applicable. If the motor's gears are stripped or windings are open, replace the transfer case shift/gear motor (verified Mopar PN 68450803AA for 2019-2025 DT; actuator 68369691AD) and reprogram if required. Keep the connector clean and protected from salt; for trucks used in snow/off-road, periodic inspection prevents being stranded in the wrong mode.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar 68089746AC transfer-case actuator
Confirm VIN, case tag and connector because the catalog also covers HD trucks and not every 1500 configuration.
- Replacement 914-006 7-pin BW44-44/BW44-45 transfer-case motor
The listing excludes 2016, so do not extrapolate.
- Genuine Mopar 68679351AA active transfer-case shift motor
Confirm VIN and transfer-case sales code.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
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U0103 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0103 mean?
U0103 stands for "Lost Communication With Gear Shift Control Module "A"." Sets when a module loses data-bus communication with the Gear Shift Control Module 'A' (electronic/shift-by-wire gear selector) and no longer receives its expected messages. Common on vehicles with electronic shifters.
What are the most common causes of U0103?
The most common causes of U0103 are: Open, shorted, or chafed bus wiring to the shift control module, Corroded or loose shift module connector, Blown fuse / lost power or ground to the module, Low battery voltage, Failed gear shift control module. The specific cause varies by vehicle.
How much does it cost to fix U0103?
Repair costs for U0103 range from $300 to $900, depending on the vehicle and root cause.
Which vehicles are affected by U0103?
Au7o has documented U0103 across 1 vehicle models from 1 manufacturers: RAM.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.