U2620

Code

Generic U — Network/User

Invalid Encryption Key Length

Brand: Generic

Type: U — Network/User

Views: UK: 18 EN: 13 RU: 14

AI status

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Page language: EN

Control module configured to use a different encryption key size than other nodes
Corrupt or truncated encryption key stored in an ECU or secure element
Incomplete or failed programming / calibration update
Diagnostic tool or tester using incorrect security parameters
Aftermarket or replacement module with incompatible security settings
Message framing or network corruption causing incorrect length field

Read and record full DTC text and any freeze-frame or extended data
Verify software/calibration part numbers of involved ECUs and gateway
Confirm diagnostic tool supports the vehicle's security protocol and has latest software
Capture raw network traffic (CAN/CAN-FD/DoIP) during authentication to view key-length field
Check for recent programming, module replacement, or aftermarket devices
Inspect wiring, connectors, and ground integrity for the affected modules

Record the DTC, any freeze frame and related U-codes. Note module IDs and software versions.
Attempt to recreate the fault: start a secure diagnostic session and capture raw network frames with a CAN/CAN-FD/DoIP logger to confirm the reported key length value.
Compare the captured key length field with the expected key length from service documentation or ECU calibration.
Verify diagnostic tool settings and update tool firmware; retry authentication using a known-good OEM tool if available.
Check recent service history for programming, module replacement or aftermarket installation; if present, confirm correct programming procedure was used.
If key length differs due to software mismatch, update/reflash the affected ECU(s) to the correct calibration/software per manufacturer procedure.
If data in ECU NVM appears corrupted, perform recommended reprogram/recover sequence (follow OEM security access and reflash procedures).
If message truncation or bus errors were observed, diagnose network health (termination, wiring, ground, CAN transceivers) and repair as needed, then retest authentication.
After corrective action, clear codes and verify stable secure communications over multiple ignition cycles and drive conditions.
If the module still reports an invalid key length after correct software and healthy bus, consult manufacturer security documentation and consider module replacement or return to supplier.

Software/calibration mismatch between master security manager and subordinate ECU (expected key length differs)
Failed or interrupted ECU reflash left an invalid key in NVM
Third-party module installed that doesn't support vehicle security key size
Diagnostic tool set to wrong security protocol (bit length/algorithm) when requesting access
Network noise or bus errors truncated the security message length field