2009 Saturn Sky 2.4L

Hey there,

I had a 2009 Saturn Sky 2.4L roll into my bay today, only one current code of a B0081-71

B0081 | Passenger Presence System 1 Invalid Serial Data Received (Symptom 71) - Current DTC, History DTC, Warning
Indicator Requested.

So I verified powers and grounds to the PPS under the passenger seat, and then I scoped the signal wire coming from the sensor in the seat, and I was getting a weird communication voltage around 7.6V

I was just wondering if that would be normal on a Saturn of this vintage?

Here is a screen shot of the data. I've also attached the systemscan and the scope capture. I just thought it was odd at 7.6V instead of a 5V or a 12V signal.

Thanks in advance.

-Ryan

GM class 2 serial is 7 V nominal pulses so that's probably what it is. Usually it's used for comms between modules though. I haven't seen it used between a module and a sensor.

Looking at the diagram again it was the module in the seat to the main airbag module that I was scoping at not the sensor on the top of the seat.

Module to module makes more sense. Was it a purple wire?

Definitely looks like Class 2 message. That year of GM would have switched over to High and Low Speed CAN for most modules, but it wouldn't surprise me at all if they still used a dedicated Class 2 between the SDM and the PPS.