U0403Invalid Data Received From Transfer Case Control Module
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- U0403 points to data from the transfer case control module, the unit that engages four-wheel drive and selects the range: its frames keep coming, yet the listener rejects what they carry. In GM's 2025 tables the ECM watches the secondary-axle signals from this module for faulty rolling counter, protection value or checksum, needs 8 bad results out of 18 to fail and assigns Type B (MIL on the second trip), whereas the lost-contact code U0102 there is Type C. On 2014-2016 Silverado, Sierra, Tahoe and Escalade GM saw U0403 with a Service 4WD message when ignition 1 voltage dropped out at fuse block terminals (PIT5391A). On 2019-2020 Ram 1500 with electronic transfer cases, U0403 and U1440 with traction lamp, driveline bumps and motor clicking were fixed by new drivetrain module software (08-083-20). U0303 is a software conflict.
- What you may notice
- Service 4WD message
- Traction control or check engine light on
- Driveline bumps or clicking from the transfer case motor
- Likely causes
- LikelySoftware of the transfer case or drivetrain control module (update available)
- PossibleIgnition voltage dropping out at fuse block terminals or relays
- PossibleFaulty range position sensor making the module send implausible values
- RareTransfer case control module internally faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.