Throwing code-Navitas controller

[Ghost407]

Just a heads up. I just found the issue with mine. I tested the resistance across the temp sensor and it was within specs. Upon looking a bit closer, the two-wire wiring connector that connects the motor temp sensor to the main harness had a loose wire. The Green/Black wire going into it connector had come out, as well as the contacts inside the connector were a bit corroded. I cut the connector off and installed a new Deutsch connector in its place. Code is now gone.

Hope that is your issue as well. WAY less expensive than a new motor!

[Clifford04]

Originally Posted by Ghost407

I just installed a brand new Tac2 on my 09 RXV last night and it is throwing the same code. Please let me know what you figure out on it.

So he mentioned the temp sensor is bad....problem from what I can see is rxv temp sensors are inside of the motor casing and not replaceable?

I did briefly see something about running a 700ohm resistor to make it read right, but any clarity on that?

I’m waiting for a call back from the tech to further discuss. I’ve read a new controller fixes it from other threads, but I’m trying to find the best solution.

[BobBoyce]

Just so you all know, if you have not spent the time reading old posts here...

Older RXVs tend to suffer from harness and connector corrosion problems. Just changing one controller for another is not going to fix the underlying harness problem that caused the origional controller to stop working. Motor speed sensors frequently fail, a temperature sensor (a thermistor) is buried in the windings and sealed in place. They are rarely the cause of a failure, as there is nothing to fail in them. They are just a type of resistor that changes its value over a temperature range. No moving parts or electronics to fail or burn out! If a code shows a failed temperature sensor, 99.999% of the time it is an electrical problem in the harness or a connector. A motors windings can cook off its insulation, and the thermistor will usually survive. We use thermistors in aerospace applications, and they are the most reliable sensors on board. They indicated hot gases inside of the wing of the space shuttle prior to the failure of the wing and ultimately the loss of the space shuttle during re-entry. I've lost more friends during the shuttle program alone than the number of failures of temperature sensors in my entire career in aerospace engineering.

[Clifford04]

Originally Posted by BobBoyce

Just so you all know, if you have not spent the time reading old posts here...

Older RXVs tend to suffer from harness and connector corrosion problems. Just changing one controller for another is not going to fix the underlying harness problem that caused the origional controller to stop working. Motor speed sensors frequently fail, a temperature sensor (a thermistor) is buried in the windings and sealed in place. They are rarely the cause of a failure, as there is nothing to fail in them. They are just a type of resistor that changes its value over a temperature range. No moving parts or electronics to fail or burn out! If a code shows a failed temperature sensor, 99.999% of the time it is an electrical problem in the harness or a connector. A motors windings can cook off its insulation, and the thermistor will usually survive. We use thermistors in aerospace applications, and they are the most reliable sensors on board. They indicated hot gases inside of the wing of the space shuttle prior to the failure of the wing and ultimately the loss of the space shuttle during re-entry. I've lost more friends during the shuttle program alone than the number of failures of temperature sensors in my entire career in aerospace engineering.

That’s insightful, thank you! I came to realize the temp sensor is buried once I took that black cap off. I’m not seeing any wiring issues, aside from the initial battery gauge dilemma. So would the controller be shot or the motor itself?

[BobBoyce]

More than likely the controller

[Clifford04]

So after speaking with the Navitas rep, who btw extremely helpful and friendly, he said that the resistor trick is needed.

Anyone have a little write up on this? I was going to get the below from amazon since it seemed like the easiest choice with shipping and everything.

EDGELEC 100pcs 470 ohm Resistor 1/4w (0.25 Watt) ±1% Tolerance Metal Film Fixed Resistor, Multiple Values of Resistance Optional https://www.amazon.com/dp/B07HDFBR2P..._AcNaFbAXCH11P

Appreciate any additional help wrapping this one up!

[BobBoyce]

Originally Posted by Clifford04

So after speaking with the Navitas rep, who btw extremely helpful and friendly, he said that the resistor trick is needed.

Anyone have a little write up on this? I was going to get the below from amazon since it seemed like the easiest choice with shipping and everything.

EDGELEC 100pcs 470 ohm Resistor 1/4w (0.25 Watt) ±1% Tolerance Metal Film Fixed Resistor, Multiple Values of Resistance Optional https://www.amazon.com/dp/B07HDFBR2P..._AcNaFbAXCH11P

Appreciate any additional help wrapping this one up!

You should ask Navitas to add a simple routine to the software in the Navitas controller to allow it to be calibrated to the temperature sensor used in the motor. E-Z-GO has used a couple of different thermister value ranges in RXV motors over the years, so any aftermarket controller for the RXVs should be capable of being adjusted for that.

[Clifford04]

Originally Posted by BobBoyce

You should ask Navitas to add a simple routine to the software in the Navitas controller to allow it to be calibrated to the temperature sensor used in the motor. E-Z-GO has used a couple of different thermister value ranges in RXV motors over the years, so any aftermarket controller for the RXVs should be capable of being adjusted for that.

Wouldn’t I have to send it in for that? You’re saying they should be able to adjust the value of the temperature to be the new normal? It says 175* Always right now, but I don’t think that’ll ever change.

[BobBoyce]

Originally Posted by Clifford04

Wouldn’t I have to send it in for that? You’re saying they should be able to adjust the value of the temperature to be the new normal? It says 175* Always right now, but I don’t think that’ll ever change.

Yes, they need to add an adjustment so that the temperature sensor can be calibrated, if they expect their aftermarket controller to be 100% compatible with all RXVs.

[Clifford04]

Originally Posted by BobBoyce

You should ask Navitas to add a simple routine to the software in the Navitas controller to allow it to be calibrated to the temperature sensor used in the motor. E-Z-GO has used a couple of different thermister value ranges in RXV motors over the years, so any aftermarket controller for the RXVs should be capable of being adjusted for that.

The Navitas rep said they couldn’t do that type of programming with that sensor.

Any other ideas or should I try the resistor trick? Or just bite the bullet and get a new controller? Navitas said it doesn’t sound like the controller is the issue.

I can test anything if you need to know values with a multimeter, just need some help with understanding what to look for.

Greatly appreciate the help this far.