This code indicates that a control module has detected an invalid, degraded, or out-of-specification authentication signal during serial data bus communication. It typically occurs when interconnected modules fail to properly validate security handshakes, preventing cooperative operation. The failure usually stems from network integrity issues rather than the modules themselves.
Corrosion, moisture intrusion, chafing, or high-resistance connections in the serial data circuits disrupt the precise voltage levels required for authentication signals.
Open, shorted, or out-of-specification 120-ohm resistors cause signal reflection and waveform distortion; total resistance measured between diagnostic link pins 6 and 14 should approximate 60 ohms.
The module responsible for coordinating authentication handshakes may fail to generate or validate security tokens due to internal circuit faults.
Weak batteries, poor charging systems, or high-resistance grounds cause voltage drops that corrupt digital signals during transmission between modules.
Non-factory alarm systems, remote starters, or diagnostic equipment can inject electrical noise or incorrect data onto the bus, interrupting authentication sequences.
Rare; the engine computer may have damaged internal communication circuits, but only after verifying wiring integrity, network topology, and other modules.
Temporary at best. If the underlying wiring, termination, or authentication issue persists, the code will return immediately and the vehicle may not restart.