What does no bus mean on a Chrysler PT Cruiser?

"No BUS" on a Chrysler PT Cruiser (and many other vehicles) indicates a communication problem within the vehicle's electronic control system. The "BUS" refers to the Controller Area Network (CAN) bus, a digital communication system that allows different electronic control modules (ECMs) – like the engine control module, transmission control module, and airbag control module – to talk to each other.

A "No BUS" message means that the communication lines between these modules are interrupted, preventing them from exchanging vital information. This can lead to a wide range of problems, from malfunctioning gauges and warning lights to complete system failures. The cause could be anything from a blown fuse, a faulty wiring harness, a failing ECM, or even a corroded connection. A proper diagnostic scan using an OBD-II scanner is needed to pinpoint the exact cause.