Few seemingly unrelated issues after install of Android head unit

[Christon]

Hi all, was seeking some advice about an install of the head unit as linked here

I had it installed professionally however afterwards my car was giving an engine malfunction warning, my cruise control was no longer working and my heated seating was no longer working.

I have enquired with the place who did it but they're avoiding my calls and messages, however they did tell me "Did you realize your check engine light is on" so as to claim in advance that their work didn't cause it.

I've replaced head units before but chose to get this done professionally because I was worried I'd do a bad job... well. I pulled my car apart, put the old head unit back in and turned the car on, still saying engine malfunction. I didn't test the cruise control when doing this.

So at this point I was happy to say whatever the car audio guys did it is likely they installed it as planned and as well as possible, and likely didn't realise the engine malfunction warning message wasn't on prior to the install. So at this point I feel they did a legit job just with a few unfortunate consequences. I don't blame them for it because they told me in advance that sometimes these chinese brand units don't come with the right harnesses. Although this one fitted okay, it gave me the impression that they aren't fans of them and sometimes cause problems. However as I say, I put my old one back in and the problem remained. I since put the new one back in and have left it running with the new one.

The head unit runs very well also, if nothing else went wrong with my car, I'd be over the moon with it.

I have tried unplugging and replugging the battery as someone suggested, I have the following DTC codes:

• 90BD13
• C41668

Basically I'm wondering what the problem could be, is it something I could fix myself or take in somewhere?

I have a booking with Autobahn on Friday, but if there's a better resolution that I may be capable of myself I'd prefer that.

The car literally runs great otherwise, if there's a genuine engine malfunction, it doesn't seem too significant.

Thankyou.

Edit: Forgot to mention the car is a Ford Mondeo MA 2009 TDCI Auto