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Home / DTC / U0427 — Invalid Data Received From Vehicle Security Control Module

U0427 — Invalid Data Received From Vehicle Security Control Module

Detailed page for trouble code U0427.

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U0427

HYUNDAI U — Network/User

Invalid Data Received From Vehicle Security Control Module

Brand: HYUNDAI
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty Vehicle Security Control Module (VSM) or Body Control Module (BCM) software bug
  • Poor CAN bus wiring or connectors (open/short/loose/poor ground)
  • Low or unstable battery/voltage during communication
  • Aftermarket alarm/immobilizer or incorrect installation interfering with messages
  • Corrupted module programming or VIN/parameter mismatch after replacement
  • Intermittent bus noise, missing termination, or shorted CAN High/Low

Symptoms

  • MIL (Check Engine or SECURITY lamp) illuminated
  • Engine cranks but will not start or starter inhibited by immobilizer
  • Keyless entry, remote start, or key recognition problems
  • Security/immobilizer warning light or messages on cluster
  • Intermittent communication-related functions (door locks, alarm, PKE)

What to check

  • Read and record all stored U- and P-codes and freeze frame data with a capable scan tool
  • Check for other network communication codes (U0100, U0073, U0401, etc.)
  • Verify battery voltage at rest and during ignition cranking (12.4–12.8 V nominal)
  • Inspect VSM/BCM connectors and harness for corrosion, bent pins, or damage
  • Check CAN High/Low voltage at VSM connector with key On: approx. 2.5 V idle differential (2.5 V each with ~0.5 V differential when active)
  • Scan module information: software part numbers, VIN, and programming status for the VSM and related modules

Signal parameters

  • CAN message IDs from VSM (security/immobilizer messages) and their periodicity (frequency)
  • Payload fields: immobilizer enable/disable flag, key ID/rolling code data, door lock/unlock status
  • CAN High/Low steady voltages (approx. 2.5 V) and differential levels during message transmission
  • Message checksum or CRC fields if available from manufacturer documentation
  • Response time and timeout errors between VSM and other modules

Diagnostic algorithm

  1. Use a scan tool to capture all U-codes and related module communication faults; note freeze frame and occurrence conditions.
  2. Verify battery state of charge and terminal condition. Charge battery to full and retest if voltage low.
  3. Inspect VSM connector and harness for damage, corrosion or loose pins; repair as needed.
  4. Check CAN bus health: measure CAN H/L idle voltages, check for ~60 Ω termination, and use a scope to observe message waveforms and noise.
  5. If noise or corrupted frames are present, isolate sections of the network (disconnect non-essential modules or aftermarket devices) and re-test to find source.
  6. Confirm no recent incompatible module replacement or incomplete programming. Retrieve module software IDs and compare to OEM specs.
  7. Temporarily disconnect aftermarket security/alarm equipment and retest for code recurrence.
  8. If wiring and external devices check OK but invalid data continues, attempt to reprogram/update VSM software per OEM procedure or perform recommended reinitialization/learn procedures for keys and immobilizer.
  9. If reprogramming fails and communication remains invalid, follow manufacturer's module replacement procedure and program the new unit to vehicle; clear codes and verify repair.
  10. After repair, road-test and re-scan to confirm code does not return.

Likely causes

  • Damaged or corroded connector at VSM
  • Frayed or pinched CAN wiring near doors/dash
  • Weak battery or poor battery terminal connection during a module update
  • Recent replacement or programming of VSM or other modules without proper VIN configuration
  • Aftermarket security device injecting invalid messages onto CAN bus

Fault status

⚠️ Status
Invalid data received from Vehicle Security Control Module (VSM). Communication error or corrupted/ unexpected security data detected on the vehicle network. Inspect VSM, CAN bus wiring, connectors, battery voltage and any aftermarket security devices.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0426 U0401 U0100 U0073 U0121
371

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