U0404

Invalid Data Received From Gear Shift Control Module A

Network / communication Generic OBD-II Medium

What it means

U0404 means a module is receiving data from gear shift control module A that is out of range or implausible. On shift-by-wire vehicles this governs gear selection, so the transmission may drop into limp mode or refuse to change gears. You can usually limp a short distance, but have the module's wiring, shifter sensor, and software checked before driving far.

Medium

Can I keep driving? Short trips only — on shift-by-wire vehicles, invalid gear-selection data can force limp mode or prevent gear changes; get it diagnosed before driving far.

Real-world scan data

Seen in

416

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of U0404 scans

P1FC0in 66.8% of scans

B1709in 63.9% of scans

U0146in 63.9% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Transmission or gear-selector warning light on
Gear position mismatched, missing, or not selectable (shift-by-wire)
Transmission stuck in a fixed gear or limp mode
Other modules storing 'lost communication' or 'invalid data' codes for the gear shift module

Common causes

Most likely first

Gear shift control module broadcasting out-of-range or implausible values onto the busLikely
Internal gear shift module fault or corrupted softwareCommon
Wiring, connector, or ground fault at the module corrupting bus dataCommon
Shifter position sensor feeding the module impossible readingsLess often

How to diagnose & fix

Work through it in order

Scan all modules and record every stored code, including companion communication codes.
Check gear shift module power, grounds, and connectors.
Inspect the shifter and module wiring for damage or corrosion.
Verify module software; reflash or replace and program if internally failed, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with U0404?+

Only briefly. On shift-by-wire systems, bad gear-selection data can force limp mode or block gear changes, which can leave you unable to select a gear. Get it diagnosed before driving far.

Can I just clear U0404?+

It returns until the fault is repaired. The gear shift module is still reporting invalid data, so the wiring, sensor, or module problem must be fixed first.

Read & clear U0404 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX