U0404 on RAM
Invalid Data Received From Gear Shift Control Module A
U0404 on RAM vehicles indicates invalid data received from gear shift control module a. Au7o has documented this code across 1 RAM model — most commonly on 1500. Sets when a module receives invalid data from Gear Shift Control Module 'A' (shift-by-wire) over the bus. Bus integrity, calibration, or module faults are typical. Typical repair costs on RAM range from $300 to $900, depending on the specific model and root cause.
Common Causes of U0404
- •CAN bus wiring fault or poor ground
- •Weak battery / low voltage
- •Calibration mismatch
- •Failing gear shift control module
U0404 on RAM by Model
RAM 1500(1 issue)
- Transfer Case Shift Motor / Actuator Failure ('Service 4WD', Won't Engage 4-High or 4-Low)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.
Looking for U0404 on a different make?
View U0404 across all makes →Frequently Asked Questions
What does U0404 mean on RAM?▼
U0404 stands for "Invalid Data Received From Gear Shift Control Module A." Sets when a module receives invalid data from Gear Shift Control Module 'A' (shift-by-wire) over the bus. Bus integrity, calibration, or module faults are typical. On RAM specifically, this code is documented across 1 model.
What causes U0404 on RAM vehicles?▼
Common causes on RAM: CAN bus wiring fault or poor ground, Weak battery / low voltage, Calibration mismatch, Failing gear shift control module. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U0404 on a RAM?▼
Repair costs on RAM range from $300 to $900, depending on the specific model and root cause.
Which RAM models have U0404 documented?▼
Au7o has documented U0404 on 1 RAM model: 1500.