ABS/TRC/VSC light constantly on

[Isthatasupra]

Hi all, 

My brother-in-law bought a 2005 Celica GT 1.8 VVTL-i yesterday from a private seller and when he got it home, we realised that the ABS/TRC/VSC lights were all constantly lit. He states it wasnt there when he test drove it. We pulled the codes from the OBD-II port, which showed a throttle position sensor fault and 4 x unknown faults. No indication of any braking faults on diagnostics. 

He says on drive home he did "get a cool little wheelspin out of it". 

We had a look on here, as well as general google searches and found a few suggestions such as check brake bulbs (all intact and working), starting with brake pedal depressed or headlights off (no change). We then found that holding TRC button before starting makes all the warning lights disappear, but after going out for a drive today, the warning ights came back on. He states he pushed the car up to the rpm for VVTL-i boost/lift to become active, but says nothing else occured. 

Looking at its history, it has had Yaw Sensor replaced a few years back. 

It had new calipers/pads/discs last year. No noise or pulling on braking. 

I wondered if the VVTL-i kicking in may cause the ABS/TRC/VSC to freak out and turn off. 

After a few dead-ends with suggestions from Google, I thought I would put it out there to see if anyone had any suggestions to try. 

Thanks in advance