Hey, I have a 2007 350z that’s my daily driver. It went into limp mode at 1500rpms and the gas gauge went all the way to empty with a full tank. I replaced the sending unit and now the rpm gauge is also at zero but everything still lights up. So I replaced the crank position sensor and still nothing. I got a nice code reader snd the code it’s giving me is from the BCM and it’s a U1000 Can communication error along with a c1729 Vehicle Speed Signal Error. I’ve checked ground wires, fuses, disconnected the battery and I’m kind of at a loss for what to do next. Any advice or ideas where to check next?

 

If I remember correctly - vehicle speed is generated from the wheel speed sensors. I would inspect the wheel speed sensor wires from each wheel their respective main harnesses. I will admit that this is not likely the culprit (especially with a U1000) but check wheel speed sensor wires.

From there I believe the 8 wires (two wires per wheel) go to the ABS Control Unit and the speed signal is sent out via the CAN bus. I believe the unified meter grabs that data off the CAN Bus network and sends an 8pulse signal to the speedometer.

so check the wiring between the ABS unit, the unified meter control unit and the speedometer and just look for damaged wires. If you have questions on where I am pulling this data I can reference it and you can translate that to the HR FSM.

If you getting a CAN Bus communication error, a dead speedometer, and an erratic fuel level sensor than I suspect it’s something to do with the unified meter controller

My caveat here is that I dont have amazing experience with this protocol and I am just using deductive reasoning from the factory service manaul … AND … this is all from my experience with the 2003 DE z and Nissan may have made changes in later model years.