What it means
A receiving module has received implausible or invalid data from restraints system sensor M. The exact sensor and affected restraint functions depend on the vehicle.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
Restraints system sensor M sends data to the restraint control system for use in managing airbags or other safety restraints. A receiving module sets U047D when the data attributed to sensor M is implausible or invalid; the sensor's location and role vary by vehicle.
Common causes
Most likely first.
- Faulty restraints system sensor or its wiring/connector
- Poor sensor power or ground
- Restraints control module or network fault
Symptoms
- SRS/airbag warning light
- Related restraint functions may be disabled
How to diagnose it
- Use an SRS-capable scan tool to record the reporting module, related codes, and freeze-frame data before clearing anything.
- Check vehicle service information to identify sensor M and its restraint function, because the letter alone does not establish a universal location.
- With the ignition off and following the manufacturer's SRS safety precautions, inspect sensor M's connector and harness for damage, corrosion, looseness, or signs of a previous repair.
- Check sensor M's power and ground connections using the vehicle wiring diagram and compare measurements with the manufacturer's specification.
- Compare sensor M's live data and status with related restraint sensors using an SRS-capable scan tool, then investigate the sensor, control module, or network if the invalid data returns.
Common fixes
- Repair a loose, damaged, or corroded sensor M connector or harness.
- Restore a poor power or ground connection to sensor M.
- Replace sensor M if its data remains implausible after its wiring and supply checks pass.
- Repair or replace the restraint control module or network connection if testing identifies that fault.
Can I keep driving?
Treat the SRS warning as evidence that one or more restraint functions may be unavailable, and arrange diagnosis promptly. Avoid disturbing restraint wiring; if the warning is on, do not assume the airbags or related restraints will work as intended in a crash.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.