U0404 code meaning
Invalid Data Received From Gear Shift Control Module A
Network system Generic code U04xx codes Check engine light
What U0404 means
Gear shift control module A is the electronic selector of shift-by-wire cars: lever, dial or buttons that report the chosen range as data. U0404 means its messages still arrive but the receiver, usually the transmission controller, rejects them. GM's 2025 ECM checks counter and protection fields of the selector's position-sensor and self-check signals, fails a signal after 4 errors in 10 or 8 in 18 checks; the code is Type B with two trips. FCA stored U0404 in the TCM of 2016 Durango and Grand Cherokee eight-speeds with MIL and a blinking M on shifter and cluster, cured by TCM software (21-011-16 Rev. A). Audi found U040400 in the gearbox unit of 2021 A6/A7 models with an intermittent selector lever fault message and no range selectable; the gateway J533 needed new software. U0103 means lost contact, U0304 a software conflict.
U0404 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0404
- Selector fault message or flashing range indicator
- Range cannot be selected or vehicle stays in Park
- Check engine light
Common causes of U0404
- Most likelySoftware of TCM or gateway (update available)
- PossiblePosition sensor or electronics in the selector delivering implausible values
- PossibleConnector or bus line at the selector loose or corroded
- Less likelyGear shift module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Gear shift moduleCAN bus wiring
What each part of U0404 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 04 | The exact fault in that area. |
What to do next
- Note U0404 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0404
What does U0404 mean?
U0404 means "Invalid Data Received From Gear Shift Control Module A". Gear shift control module A is the electronic selector of shift-by-wire cars: lever, dial or buttons that report the chosen range as data. It is a generic code, so it means the same on every make.
Is it safe to drive with U0404?
Drive gently and only to a workshop. With U0404 the car can go into limp mode (reduced power) to protect itself.
Will U0404 fail an emissions test?
Yes, it can. U0404 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0404 to fix?
Difficulty: hard. A typical repair takes 0.3 to 2.5 hours of work. This is a job for a workshop.
Will U0404 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.