What it means
A control module is not receiving expected messages from the Antenna Control Module. Antenna-related functions may be affected; the code alone does not identify why communication was lost.
How it works
The antenna control module manages antenna-related functions and exchanges status messages with other vehicle modules. U0185 is set when the reporting module misses the expected messages from that antenna module for the specified time. Possible causes include loss of module power, gateway routing problems, or a CAN termination fault; do not assume the listed 120 Ω resistor value applies to a particular vehicle without checking its specifications.
Common causes
Most likely first.
- Antenna module unpowered
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Antenna-related functions may be unavailable or impaired
- Other communication codes
How to diagnose it
- Scan all modules and examine freeze-frame data and related communication codes to check whether the fault is limited to the antenna module or affects the wider CAN network.
- Check which antenna-related functions are impaired and whether the antenna module can be reached with a scan tool.
- Inspect the antenna module connector, power and ground wiring, and CAN harness for corrosion, looseness, or physical damage.
- Verify module power and ground under the manufacturer's specified test conditions.
- Test the CAN wiring and termination as directed by the vehicle wiring diagram and manufacturer specifications; check for opens, shorts, or a termination fault.
- If supplies and network tests pass, investigate gateway routing and the antenna module with vehicle-specific diagnostics.
Common fixes
- Restore stable battery voltage or repair a confirmed power supply fault.
- Clean, secure, or repair the antenna module connector and its wiring.
- Repair CAN wiring faults found between the antenna module and network.
- Correct a verified gateway routing or CAN termination fault to the manufacturer's specification.
- Replace or configure the antenna control module only after power, ground, and network communication are verified.
Can I keep driving?
The vehicle is generally driveable if no other systems are affected, though antenna-related features may not work. If the scan shows additional network faults or other vehicle functions malfunction, have those issues assessed before continued use.
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.