Corroded, loose, or damaged electrical connector at the gear shift control module; Chafed or shorted wiring in the harness between the gear shift module and the controller area network bus; Failed gear shift control module, often due to internal circuit board faults or water intrusion; Low battery voltage or a weak charging system causing the gear shift module to transmit corrupted data; Poor ground connection shared by the gear shift module and other network nodes; Software or calibration mismatch in the gear shift control module after a replacement or update; Controller area network bus termination resistor fault that distorts signals reaching the gear shift module

DTC codes / U04xx · Invalid data received from a module / U0404

U0404Invalid Data Received From Gear Shift Control Module

Q: What does code U0404 mean?

Invalid Data Received From Gear Shift Control Module. U0404 is a communication fault where the engine control module or another primary controller receives invalid or corrupted data from the gear shift control module over the vehicle's controller area network bus. The receiving module detects that the messages contain implausible values, missing checksums, or out-of-range signals, so it flags the gear shift module as the source of the bad data.

U0404 is a communication fault where the engine control module or another primary controller receives invalid or corrupted data from the gear shift control module over the vehicle's controller area network bus. The receiving module detects that the messages contain implausible values, missing checksums, or out-of-range signals, so it flags the gear shift module as the source of the bad data.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaInvalid data received from a module

Symptoms you may notice

Illumination of the malfunction indicator lamp, often with no other noticeable symptoms
Gear selector or shifter position indicator flashing or showing an incorrect gear
Transmission stuck in a single gear or refusing to shift manually
Inability to start the engine because the shifter position is not recognized
Harsh or delayed shifts as the transmission control module defaults to a limp strategy
Electronic stability control or hill-start assist warnings appearing alongside the check engine light

Common causes, most likely first

Corroded, loose, or damaged electrical connector at the gear shift control module
Chafed or shorted wiring in the harness between the gear shift module and the controller area network bus
Failed gear shift control module, often due to internal circuit board faults or water intrusion
Low battery voltage or a weak charging system causing the gear shift module to transmit corrupted data
Poor ground connection shared by the gear shift module and other network nodes
Software or calibration mismatch in the gear shift control module after a replacement or update
Controller area network bus termination resistor fault that distorts signals reaching the gear shift module

How to diagnose and fix it

Connect a scan tool and record all stored codes in every module, then verify the gear shift module is communicating and check for related network codes
Inspect the gear shift control module connector for corrosion, pushed pins, or loose terminals and clean or repair as needed
Perform a voltage drop test on the gear shift module power and ground circuits to rule out low voltage or bad grounds
Check the controller area network bus wiring for shorts to ground, shorts to power, or opens between the gear shift module and the receiving controller
Test the controller area network bus termination resistance at the diagnostic link connector to confirm the bus is electrically sound
Substitute a known-good gear shift control module or reflash the existing module with the latest calibration and recheck for U0404
Clear codes and perform a road test through all gear positions to confirm the fault does not return

What the gear shift module data really means

U0404 is often set by a weak battery or poor ground rather than a failed gear shift module, so always load-test the battery and check grounds before condemning the module.
A gear shift control module that communicates perfectly on a scan tool can still send invalid data, so live data review of shifter position and selector signals is more useful than a simple communication check.
Water intrusion into the center console or shifter area commonly corrodes the gear shift module connector and produces U0404 without any visible exterior damage.
After replacing the gear shift control module, some vehicles require a calibration or learn procedure, and skipping it will immediately reset U0404.
A faulty controller area network bus termination resistor elsewhere on the network can corrupt signals enough to trigger U0404 even though the gear shift module itself is healthy.

Can I keep driving with U0404?

The vehicle may remain driveable, but the transmission can default to a limp mode or refuse to shift, so avoid highway speeds and stop driving if the shifter position is not recognized or the car will not start. Have the fault diagnosed promptly because an unrecognized gear position can also affect starting and stability systems.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.