Hi, thanks in advance for your help. I have a 2015 Kia Cadenza that I think was run out of fuel after sitting for a few months. It will only rev to about 2,000 RPM so it seems like it is in a low power mode or something. I took it to Auto Zone and they plugged up their computer and there was a code "P0090. I can't find out what that specific code means for this vehicle. I think it has something to do with the fuel pressure regulator which I believe is in the fuel tank at the fuel pump. It also showed code "C1649". I am pretty good at fixing my cars but I am not sure where to start with this one. I would appreciate any suggestions. Thanks
Clarification: What is the mileage? And which engine, transmission?
The internet is full of websites for researching diagnostic trouble codes (DTC). (as explained on our Frequently Asked Questions page)
P0900 being a universal code is easy to find.
One of my favourites is obd-codes.com
P0090 Fuel Pressure Regulator 1 Control Circuit Open
So your fuel pump is not delivering the pressure that car needs. There can be a few reasons like failed pump or clogged filter. The first step will be to measure fuel pressure with a gauge. Also not a bad idea to check fuses and relays.
C1649 is a little trickier because it's Hyundai specific. Just web search for "Hyundai C1649"
I came across this document defining many codes, which you should probably save:
https://www.hyundai-forums.com/attachments/hyundai-tnt_dtc_v24issue02-pdf.161962/
C1649 CAN time-out ECM for SCC
The SCC is the shorten word of Smart Cruise Control system. This system has a radar sensor on a vehicle and the SCC ECU calculates the distance between cars going in the same direction by the radar sensor. So this SCC system enables a vehicle to drive with maintaining the constant distance from the car ahead or at a constant vehicle speed. The HECU exchanges signals with SCC ECU through CAN communication.
This is network problem, so you've got a failed computer module, or wiring/connection fault, if you want to pursue that.
But I'm sure the car will work fine without the radar too.
Good luck.
