What it means
A control module has detected that the software in the remote function actuation module is incompatible with its own software or configuration. Remote-operated functions may be affected; the specific effects depend on the vehicle.
How it works
The remote function actuation module receives or coordinates commands for vehicle functions operated remotely, with the functions varying by model. U0338 sets when another module detects that this module's software or configuration is incompatible with its own expectations, which can disrupt remote commands or related functions.
Common causes
Most likely first.
- Incorrect or incompatible remote function actuation 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
- Save freeze-frame data and scan all modules for remote-function, body-system, and communication codes before clearing the fault.
- Ask whether the fault followed module replacement, keyless-entry work, or other electrical service, and verify the remote function actuation module's part number.
- Read the module's software and configuration identifiers with a capable scan tool and compare them with manufacturer data for the vehicle.
- Inspect accessible low-voltage connectors and wiring at the module for poor seating, corrosion, or damage, and note which remote-operated functions fail.
- If the part and connections are correct, have the module configured or programmed to the vehicle, then test the affected remote functions and rescan.
Common fixes
- Reconnect or repair an accessible loose or damaged module connector or harness.
- Replace an incorrectly specified remote function actuation module with the correct one.
- Program or configure the module to match the vehicle's equipment and other controllers.
- Install a manufacturer-approved software update if one addresses the incompatibility.
Can I keep driving?
If only remote-operated features are affected and the vehicle drives normally, local controls may remain usable, but verify essential functions such as locking before leaving the vehicle unattended. If access or security functions behave unpredictably, avoid relying on remote operation until repaired.
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.