I found a non-OEM electronic gadget in my car. It is wired into the ignition, and contains a 435.10 MHz radio reciever, a microcontroller, and two relays. I suspect it might be a device that allows third parties to unlock the doors and start the car with a radio.
I was driving my 2020 Honda Insight EX when it started to make the annoying sound of an electromechanical relay rapidly switching on and off. When I got home I looked under the dash and straight away I could see someone other than Honda had been in here. The first thing I saw was this surface-mounted switch that doesn't belong there.
Inside the cover of this thing is a label PL884-200. Initially I suspected this of being a miniature tracking device, but there's actually very little to it. It contains a switch and an LED. The LED won't work unless the case is assembled because there are two bridging contacts inside the case. But, mysteriously, the LED also isn't visible with the case assembled because all parts of the case are opaque. The purpose of the switch remains unknown to me.
The switch is wired into the little gadget, which is also spliced into the main ignition and the CAN bus. With the car turned on, it's clear that this gadget contains the failing relay.
With the trim removed you can see the way the device was wired in with T-taps and splices. Also some of the factory wires have been cut and just left hanging.
Naturally I removed this device and took it home. Car starts and runs without it, but every warning light on the dashboard comes on. There isn't a lot to it. In the center of the board are two relays and a darlington relay driver.
In the corner of the board is a CY800 radio receiver. With its 6.7458 MHz reference oscillator it is tuned to 435.10 MHz. Its antenna is a flexible PCB-mount part from TE Connectivity, under which is a standard LM358 op-amp.
Also under the antenna is the PIC16F1518 microcontroller, the brain of the device. The only other devices on the board are a standard 5V voltage regulator and passive components.
Things that this device does not contain include a GPS receiver and a cellular transmitter. However, it is hooked into the CAN bus so it could get GPS data and, perhaps, relay data through the HondaLink cellular device. So my operating theory for the time being is as follows:
- The device gets vehicle location data over CAN from the car's GPS.
- The device uses the car's cellular data peripheral to send this information somewhere.
- There exists some radio transmitter that can be used at short range to start the car.
- The relays are flipping out because there is some 435.10 MHz noise in my area.
If you have ever seen or installed one of these devices, please leave a comment. I'd love to know more.
Feel free to tell that to the guy who lost his life over a joke he made on Twitter