2015 California T - Accelerating on its own - AC acting Crazy - Temp needle disappearing

Yes, it sounds like the twilight zone, but I'm hoping someone has a lead for me on this one...

Just bought a 26K mile California T in near mint condition. On the way home, the center circular display went out and would not come back on. A quick forum review identified it as a common issue, so I figured I'd address it later and proceeded home. The next day (yesterday AM) I got a temp warning light as the coolant temp gauge appeared with NO NEEDLE! Then the light goes out and the needle re-appears with a normal temp reading. Soon after, the AC refused to work correctly. Now the AC is hot on one side and cold on the other, then it will flip-flop sides with it cold on the other side and hot... etc.

I started the car last night and now it has an erratic idle and it slowly surges as if someone is pressing the accelerator. It goes into gear and "drives on its own," even accelerating by itself when in gear, causing the transmission to slip a bit.

I ran a scan with the tool I use for my 360/F430 and it gave a few codes, one for coolant temp sending unit P0117 (which I suspected), and "Error Counter Of Implausible Brake States P1103.

I did the "Italian Reboot" by disconnecting the battery for 10 minutes, after which it would not start. It finally started and ran erratically again with all the same problems reappearing, including the self-acceleration issue.

Here is an important find: The car runs normal as soon as the electric fans turn on. As the fans cycle, and turn off, the car surges again into the 2K-2,500 RPM range. So, I turned on the AC, which makes the fans run constantly, and the car drives like new. This indicates a voltage tolerance issue somewhere in the failing circuit(s).

Please do not suggest that my feet are too big for the car and my foot is hitting the petal, or it's the floor mats, as what is said on other posts I've read.

I am hoping that there is an ECU or something that may control a portion of the subsystems that are in question to give an idea of the origin of these gremlins. A simple plug can cause multiple electrical issues in multiple locations.

I have rebuilt F1 era Ferraris and Maseratis but these modern cars are very complex so any outside help would be appreciated.

 

lol of course I tried that. Tapping it no longer works. The gauge is dark. Most importantly, the NEEDLE inside the coolant temp disappears and the temp light comes on. Finally, the car is surging and accelerating on its own.

If there is a harness controlling various components such as (1) TPS, (2) coolant temp sending unit, and AC then that would be a good start.

I have an appointment with Ferrari next week but I typically fix my own Ferraris, just this one is NEW to me so I'm a little bit in the dark lol.

 

The battery was new, but I installed a new one again today. Situation is worse. The car literally takes off when driving without going near the pedal, the A/C is off on the controller but it's blowing ice cold and high fan, the top now quit working as did the trunk. On the last test drive after the battery today, a puff of smoke and an electrical smell came from the AC vents. This seems serious.

I'm thinking there is a frying harness and the heat is jumping to different wires. I'll tear it down this weekend prior to sending it to Ferrari on Tuesday.

 

No warranty - as is. The problems are intermittent and all include components that have power carried through the main wire harness behind the dash. My guess would be that a multi-pin plug is fouling. If this is the case, I need to catch it in time before it generates too much heat. The good news is that if the wires themselves are burned, then the problems would be constant. If it's intermittent (which it is), then it's typically a plug. I'll be tearing into it this weekend, hopefully inspecting and cleaning all the terminals I can reach. I'm thinking the problem is somewhere near the base due to the fact that so many systems are being affected.

 

I do my own PPIs on all the cars I buy and this one turned out to be one of the more solid ones I've run across. No, it was not a F dealer, otherwise I would not have saved the $30k I saved on the purchase price. The scan came up clean, all the fluids were good, new tires, brakes were good and no leaks were detected. All the electronics were working and the title was clean as was the Carfax. When I test drove the car, after it was heated up, we pushed the car to its limit a few times and there were no hesitations. Everything looked good.

One thing I learned about Ferraris over the years is that generally low-mileage cars that have been sitting can give you big surprises once you start driving them. This is the same with Maseratis of the Ferrari era. The vast majority of my past problems have been within 48 hours of acquiring the car. This one was no exception, however the constant progression of the problems is what made this one different.

Last night I tore into all the fuseboxes and ECUs and noticed something interesting. Not only is the audio system completely modified with various components hidden away with their associated wiring, but also a radar, radar jammer, laser system has been installed and hardwired into the electrical system. This included wiring and aftermarket fuses in the passenger footwell, body computer and additional components installed in the access holes in the floor of both the driver and passenger. I am very aware of the temperamental nature of Ferrari's electrical system. My 360, for example, has a massive sound system but it's supported by an independent electrical system, battery (yes, 2 batteries), fuses and even a separate alternator cable, completely isolating it from the car's factory electrical system. The California, on the other hand, has so many components, some high end and others not even branded (like the active radar jammer which is not street legal) with nothing but a black box, a handful of power lights, and a mess of transmitters neatly installed behind the front grill.

I can only assume that if these mods are not entirely responsible for the issues, then they have certainly contributed to them.

Either way, it will be visiting the dealership tomorrow am. With any luck, the SDX will show something. I will keep everyone posted on what I or they find.

 

UPDATE on the California T:

After Ferrari PB spent hours with the car testing all the systems with the SDX, road testing, re-testing, etc., they traced the problems back to the failed coolant temp sending unit/sensor. I was aware of that failure but was unaware that it could cause a landslide of issues. I did realize that the revving started immediately once the fan turned on, which was at the same time the system quit receiving the signal from the coolant temp sensor (the needle disappears on the gauge and the coolant temp light illuminates). It seems that one fault can cause a chain reaction in dependent subsystems in the car.

I'm not totally sure that the power top issues and rear lock has any connection to this, but once the sensor is replaced, we will find out. Ferrari said the unit is backordered but I think I can get it through scuderia or Ferrparts. I'm going to start hunting today.

 

YOU WON'T BELIEVE THIS... THE CAR IS FIXED!

Turns out the coolant temp sensor is the same sensor used in 80 other model/year cars and I had a new one in my parts bin. After a quick R&R and a battery disconnect, ALL ISSUES WERE RESOLVED.

The AC now works, the center stack works, the trunk, power top, all the gauges are working and the revving problem is gone.

The takeaway: Modern Ferraris are even more temperamental with electrics than the older ones and one fault can create a landslide of symptoms. This was a $26 fix that easily contributed to the $25K savings on the purchase price. The car is now like new and performs as it should.

 

This one was from Carrio Motorcars. $84K out the door.