What it means
A control module has detected that the software in the restraints control module is incompatible with its own software or configuration. Restraint-system functions may be affected; the specific effects depend on the vehicle.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
The restraints control module manages crash-sensing and occupant-restraint functions, including airbag and pretensioner deployment decisions. U0336 is set when another module finds that the restraints module's software or configuration does not match the version it expects, which can compromise restraint-system availability.
Common causes
Most likely first.
- Incorrect or incompatible restraints control module software
- Module replacement without required programming or configuration
- Incorrect module part number
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan the restraints module and all other modules for related configuration, communication, and restraint-system codes, and save the available freeze-frame data.
- Check whether the code appeared after collision repair or module replacement, then verify the installed restraints module part number is correct for the vehicle.
- Use a capable scan tool to read the restraints module's software and configuration identifiers and compare them with manufacturer information for the vehicle.
- Visually check accessible low-voltage connectors and harnesses for damage or poor seating, without probing airbag or pretensioner wiring.
- If the part and wiring are correct, have the restraints module programmed or configured with the manufacturer-approved procedure, then rescan and confirm the warning clears.
Common fixes
- Seat or repair an accessible damaged low-voltage connector or harness.
- Replace an incorrectly specified restraints control module with the correct application.
- Program and configure the replacement or existing module for the vehicle.
- Apply a manufacturer-approved software update to the modules involved in the mismatch.
Can I keep driving?
Treat an airbag or restraints warning as a sign that some crash protection may not work as intended; minimize driving and have the system addressed promptly. Do not probe restraint wiring or rely on airbags and pretensioners until the fault is resolved.
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.