Modern vehicles are rolling computers, and their ECUs sit at the heart of safety, connectivity, and data. A leading telematics manufacturer partnered with Payatu to pressure-test a new in-vehicle unit across hardware, firmware, BLE, and cloud messaging. The engagement exposed critical gaps, from open debug interfaces to misconfigured MQTT topics, and delivered a clear remediation roadmap to harden the device before launch, protect customer data, and safeguard on-road reliability.