Code
U0427
Generic
U — Network/User
Invalid Data Received From Vehicle Security Control Module
Views:
UK: 25
EN: 79
RU: 30
AI status
Completed
Completed
100%
Causes
- Corrupted or out-of-date software/firmware in the Vehicle Security Control Module (VSCM)
- Damaged VSCM hardware (internal failure)
- Faulty CAN/LIN network (shorts, opens, high resistance, or grounding issues)
- Intermittent or corroded connectors at the VSCM or harness splices
- Low or unstable battery/vehicle voltage during module communication
- Aftermarket security/remote start/alarms interfering with or reprogramming messages
Symptoms
- Security/immobilizer warning lamp illuminated or flashing
- Engine will not crank or will crank but not start due to immobilizer action
- Remote/key fob functions (lock/unlock, remote start) may not operate reliably
- Unexpected security-related warnings/messages on instrument cluster
- Intermittent starting or random lock/unlock events
- Other modules report communication errors or related U-codes
What to check
- Verify battery voltage is within specification (12.4–12.8 V at rest); confirm charging system is working
- Capture DTCs from all networked modules; note any other U-codes or B/C/P codes that might point to the network or related systems
- Visually inspect VSCM connector and harness for corrosion, bent pins, damage, water intrusion, or poor repair splices
- Check fuses and power/ground circuits for the VSCM; verify good chassis and battery ground connections
- Scan for auth/immobilizer status (if available) and confirm correct key recognition
- Check for presence of aftermarket alarm/remote-start modules and temporarily isolate/disconnect if suspected
Signal parameters
- CAN/LIN message ID used by VSCM (varies by make) — verify expected ID appears on bus
- Data Length Code (DLC) — expected byte length for the VSCM message (commonly 8 bytes on CAN)
- Cycle time/update rate — expected message frequency (typical VSCM messages often 5–20 Hz; verify against manufacturer spec)
- Sequence counter/checksum bytes — ensure counters increment and checksum validates message integrity
- Typical bus voltages (Key ON, engine OFF): CAN_H ≈ 2.5–3.5 V, CAN_L ≈ 1.5–1.0 V; differential idle ≈ 0 V with ~2 V swing when dominant — confirm with scope
- Power supply to VSCM: battery feed near 12 V when key ON, proper ignition-switched 12 V where applicable
Diagnostic algorithm
- Connect a professional scan tool and record all stored and pending U/B/C/P codes from all modules; do not erase codes yet
- Check vehicle battery voltage and charging system; if voltage is low, charge/replace battery and retest
- Inspect VSCM connector and harness for corrosion, water intrusion, bent pins, or mechanical damage; repair any issues
- Verify VSCM power and ground circuits with a DVOM; check relevant fuses and relays. Repair any open circuits or poor grounds
- With ignition ON (engine OFF), monitor the vehicle network with a scan tool or CAN/LIN sniffer to confirm VSCM messages are present, and note message IDs, cycle time, DLC, and data contents
- If available, use an oscilloscope to view CAN_H and CAN_L signals at the VSCM and at several nodes to find reflections, missing messages, or shorts. Measure CAN bus differential waveform and check termination resistances (~60 ohms across CAN_H and CAN_L)
- If an aftermarket security device is fitted, disconnect it and retest; aftermarket devices commonly inject/modify messages causing U0427-type faults
- Check for related modules reporting lost communication or invalid data; isolate sections of the network by disconnecting suspected components one at a time and observing code behavior
- If wiring and bus integrity are confirmed, check for software updates or reflash the VSCM using manufacturer procedures; confirm correct module coding/immobilizer pairing after any replacement or reflash
- Only replace the VSCM after the network and wiring have been confirmed good and software/coding options verified; follow manufacturer immobilizer pairing/anti-theft procedures when installing a replacement module
- After repairs, clear codes and perform drive/functional tests to confirm no recurrence; if intermittent, use extended logging and road test with scan tool connected
Likely causes
- Loose or corroded connector pins at the VSCM or network splice
- CAN high/low short to battery or ground, or a short between CAN high and CAN low
- Failed VSCM due to internal electronics fault
- Failed power or ground feed to the VSCM (blown fuse, open circuit)
- Aftermarket immobilizer or alarm modifying/overriding CAN messages
- Software mismatch after module replacement or an incomplete reflash
Fault status
Status
Invalid data received from Vehicle Security Control Module
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
U0427
HYUNDAI
U — Network/User
Invalid Data Received From Vehicle Security Control Module
Views:
UK: 13
EN: 33
RU: 21
AI status
Completed
Completed
100%
Causes
- Corrupted or out-of-date software/firmware in the Vehicle Security Control Module (VSCM)
- Damaged VSCM hardware (internal failure)
- Faulty CAN/LIN network (shorts, opens, high resistance, or grounding issues)
- Intermittent or corroded connectors at the VSCM or harness splices
- Low or unstable battery/vehicle voltage during module communication
- Aftermarket security/remote start/alarms interfering with or reprogramming messages
Symptoms
- Security/immobilizer warning lamp illuminated or flashing
- Engine will not crank or will crank but not start due to immobilizer action
- Remote/key fob functions (lock/unlock, remote start) may not operate reliably
- Unexpected security-related warnings/messages on instrument cluster
- Intermittent starting or random lock/unlock events
- Other modules report communication errors or related U-codes
What to check
- Verify battery voltage is within specification (12.4–12.8 V at rest); confirm charging system is working
- Capture DTCs from all networked modules; note any other U-codes or B/C/P codes that might point to the network or related systems
- Visually inspect VSCM connector and harness for corrosion, bent pins, damage, water intrusion, or poor repair splices
- Check fuses and power/ground circuits for the VSCM; verify good chassis and battery ground connections
- Scan for auth/immobilizer status (if available) and confirm correct key recognition
- Check for presence of aftermarket alarm/remote-start modules and temporarily isolate/disconnect if suspected
Signal parameters
- CAN/LIN message ID used by VSCM (varies by make) — verify expected ID appears on bus
- Data Length Code (DLC) — expected byte length for the VSCM message (commonly 8 bytes on CAN)
- Cycle time/update rate — expected message frequency (typical VSCM messages often 5–20 Hz; verify against manufacturer spec)
- Sequence counter/checksum bytes — ensure counters increment and checksum validates message integrity
- Typical bus voltages (Key ON, engine OFF): CAN_H ≈ 2.5–3.5 V, CAN_L ≈ 1.5–1.0 V; differential idle ≈ 0 V with ~2 V swing when dominant — confirm with scope
- Power supply to VSCM: battery feed near 12 V when key ON, proper ignition-switched 12 V where applicable
Diagnostic algorithm
- Connect a professional scan tool and record all stored and pending U/B/C/P codes from all modules; do not erase codes yet
- Check vehicle battery voltage and charging system; if voltage is low, charge/replace battery and retest
- Inspect VSCM connector and harness for corrosion, water intrusion, bent pins, or mechanical damage; repair any issues
- Verify VSCM power and ground circuits with a DVOM; check relevant fuses and relays. Repair any open circuits or poor grounds
- With ignition ON (engine OFF), monitor the vehicle network with a scan tool or CAN/LIN sniffer to confirm VSCM messages are present, and note message IDs, cycle time, DLC, and data contents
- If available, use an oscilloscope to view CAN_H and CAN_L signals at the VSCM and at several nodes to find reflections, missing messages, or shorts. Measure CAN bus differential waveform and check termination resistances (~60 ohms across CAN_H and CAN_L)
- If an aftermarket security device is fitted, disconnect it and retest; aftermarket devices commonly inject/modify messages causing U0427-type faults
- Check for related modules reporting lost communication or invalid data; isolate sections of the network by disconnecting suspected components one at a time and observing code behavior
- If wiring and bus integrity are confirmed, check for software updates or reflash the VSCM using manufacturer procedures; confirm correct module coding/immobilizer pairing after any replacement or reflash
- Only replace the VSCM after the network and wiring have been confirmed good and software/coding options verified; follow manufacturer immobilizer pairing/anti-theft procedures when installing a replacement module
- After repairs, clear codes and perform drive/functional tests to confirm no recurrence; if intermittent, use extended logging and road test with scan tool connected
Likely causes
- Loose or corroded connector pins at the VSCM or network splice
- CAN high/low short to battery or ground, or a short between CAN high and CAN low
- Failed VSCM due to internal electronics fault
- Failed power or ground feed to the VSCM (blown fuse, open circuit)
- Aftermarket immobilizer or alarm modifying/overriding CAN messages
- Software mismatch after module replacement or an incomplete reflash
Fault status
Status
Invalid data received from Vehicle Security Control Module
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
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Was this AI description helpful?
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