What it means
A control module has lost communication with the vehicle security control module. Security-related functions may be affected, depending on the vehicle.
How it works
The vehicle security control module handles security-related information such as authorization or theft protection, depending on the vehicle. This code sets when another module stops receiving expected messages from that module, which can affect security functions or starting authorization.
Common causes
Most likely first.
- Loss of module power or ground
- Open, shorted, or damaged communication wiring or connector
- Module or gateway fault
Symptoms
- Security or key warning
- Starting or security functions may be affected
- Communication faults in other modules
How to diagnose it
- Scan all modules for U0119 and security or immobilizer codes, noting which modules cannot communicate with the vehicle security control module.
- Check freeze-frame data and ask whether the fault coincided with a no-start, key warning, battery discharge, or recent electrical work.
- Inspect the security module's connectors and harness for loose terminals, corrosion, moisture, or damage.
- Check its power and ground circuits using the wiring diagram and the manufacturer's specification.
- Test the module's network wiring for opens, shorts, or poor connections, and check any related gateway connections.
- If the wiring and supplies pass, use vehicle-specific diagnostics to determine whether the gateway or security module has failed.
Common fixes
- Secure or repair a loose, damaged, or corroded security module connector.
- Restore a failed power feed or ground to the vehicle security control module.
- Repair an open or short in the module's communication wiring.
- Repair a confirmed gateway fault or replace and configure the security module if it is proven faulty.
Can I keep driving?
If the security or key warning is on, the vehicle may fail to start or security features may not work; avoid switching off in an unsafe location if starting is already unreliable. If it will not start or the security system behaves unpredictably, arrange assistance.
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.