Hi

the speedometer on my 09fx35 2wd quit working at 16Ok miles
He i started the car, the needle on speedometer and Rpm goes all the way to max and back to 0.

However when i drove it, speedometer wasnt working, while Rpm works.

Obd reader showed p0500 and p1078

Any idea how and what need to be replaced, i need to fix it so i can smog it to renew my calif registration

Thx

Unless you're getting an ABS light and some other gauges are also out, that sounds like a communication issue between the cluster and the Meter/AC Amp. The Amp is the boss and it's CAN-connected, the cluster isn't. The cluster gets its info from the Amp on a local bit-bang line (LIN). Your FX doesn't have a traditional VSS for the speedo signal, it strictly gets the vehicle speed from the ABS. The Amp gets the signal on CAN and then passes it to the cluster. Since the needle sweeps on bootup, it's doubtful the problem is in the cluster itself, and if your other gauges work, it's doubtful the Amp is dead. So you may not straighten it out without a comprehensive scan of all the vehicle systems.

The P1078 is more straightforward, it's a problem with the exhaust cam sensor on the passenger side bank. It's a "flatline" code, so most probably it just means a bad sensor.