Has anyone else noticed intermittent check engine lights or erratic instrument cluster behavior on modern OBD-II equipped vehicles (post-2010 models, especially those with CAN bus networks) when parked within 50-100 feet of a mechanic shop for extended periods, such as overnight? I’ve documented this on three separate vehicles-a 2018 Honda Civic, 2022 Toyota RAV4 Hybrid, and 2021 Ford F-150-all triggering P0606 (ECM/PCM Processor fault) or U0100 (Lost Communication with ECM/PCM) codes exclusively after proximity to shops using high-power diagnostic tools like Launch X431 or Bosch KTS scanners.
Common misconception: This isn’t “ghost codes” from faulty wiring or bad grounds, which typically persist across locations. Instead, it’s likely RF interference from bidirectional scan tools operating in the 433-434 MHz ISM band or WiFi-enabled programmers (2.⅘ GHz) radiating unshielded signals during active sessions. Shops often leave tools in “scan mode” unattended, creating a localized EMI field that couples into vehicle antennas or wiring harnesses via capacitive or inductive paths, corrupting ECU memory or CAN high/low lines.
To verify: Park 200+ feet away and monitor-no recurrence. Use an SDR (software-defined radio) like RTL-SDR to spectrum-analyze the area; peaks at scanner frequencies correlate directly. Mitigation: Faraday pouches for key fobs (prevents remote wake-up amplifying susceptibility), or request shops disable WiFi/RF on tools post-use per SAE J2450 guidelines. Shops, if reading: Comply with FCC Part 15 shielding requirements to avoid nuisance faults costing owners $100+ in false diag fees.
Data logs attached (voltage spikes on CAN bus during exposure). Thoughts on root cause or permanent fixes?