U0427: Invalid Data Received from Vehicle Security Control Module

What it means

The vehicle security controller delivers data that does not pass plausibility checks. Alarm system or remote unlocking can behave erratically.

How it works

The vehicle security control module sends status data over the vehicle network, such as information used by alarm and remote-entry functions. A receiving module sets U0427 when that security data fails its plausibility checks, potentially because the security module is faulty or the gateway or CAN network is corrupting or routing messages incorrectly.

Common causes

Most likely first.

1. Security module failed
2. Gateway module routing CAN messages incorrectly
3. CAN terminating resistor (120 Ω) drifted out of spec

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

1. Scan all modules for codes and review freeze-frame data to identify which module logged U0427 and whether other communication faults appeared at the same time.
2. Check whether the alarm, remote unlocking, or other security-related functions are behaving erratically, and note which functions are affected.
3. Inspect the security module and gateway connectors and visible CAN wiring for loose connections, corrosion, damage, or signs of water intrusion.
4. Use a scan tool to compare the security module's reported status with the vehicle's actual alarm and lock state, if those data are available.
5. Have the CAN network and its termination checked against the manufacturer's specification before condemning the security module or gateway.

Common fixes

• Repair a loose, corroded, or damaged connector or CAN wire at the security module or gateway.
• Correct a CAN termination fault if testing confirms the network resistance is outside the manufacturer's specification.
• Repair or replace the gateway if it is routing security messages incorrectly.
• Repair or replace the security control module if its data remains implausible after network faults are ruled out.

Can I keep driving?

If the vehicle drives normally and no safety systems are affected, a short trip may be possible, but alarm or remote-entry functions may be unreliable. Multiple warning lights, shutdowns, or limp mode warrant stopping somewhere safe and arranging diagnosis.