U0402Invalid Data Received From TCM
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U0402 is the reverse case of U0401: the engine controller or another listener receives the transmission controller's frames but rejects their content. GM's 2025 ECM checks counter, protection value and checksum of the estimated-gear and general transmission information signals, flags a fault at 8 errors among 18 checks, Type A after one trip; the body controller uses 15 of 16 and Type B. Saab's 2011 list names sub-codes 72 (counter), 73 (parity) and 74 (checksum). On the 2022 Ram 1500 5.7 L eTorque the PCM, once U0402 is set, refuses torque requests from the TCM, the gearbox falls into a fixed limp gear and the MIL lights; PCM software (18-001-23) cures it. On 2014-2015 Cherokee and 200 nine-speeds FCA traced U0402 and a rough 5-4 downshift to the C-clutch snap ring (21-008-15). U0101 is lost contact.
- What you may notice
- Check engine light
- Transmission stuck in a fixed gear (limp mode)
- Harsh or delayed shifts
- Likely causes
- LikelySoftware of PCM or TCM (update available)
- PossibleInternal transmission fault making the TCM send implausible values
- PossibleDisturbed CAN traffic from connectors, wiring or low voltage
- RareTransmission control module internally faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.