I have encountered this code before we found pot was blowing out often cat has a bulliten out that puts shunts on the pot wiring and that didn't help we found that the operator was going from forward to reverse to slow lift and this was when the code was thrown

Dino,
well it doesn't check the calibration as much as it checks for a certain expected voltage when the handle is in the neutral range.
Here are the voltage ranges for the travel pot, this may be of some help.
Full Forks First = 2.75 - 4.75
Neutral = 2.0 = 3.0 (the ideal setting would be around 2.5v)
Full Tractor First = 0.5 - 1.75

I could try and explain how to get into the TMM so you can run a learn on the handle but if you've never done it before you would need some first hand (someone present),guidance the first time. It would be best if you had someone that's worked on these or Raymond trucks before (these are the same), and/or call a cat tech out.
And if you ever decide to change out the VR1 you defiantly would need someone that's done it before.

Good Luck

Swoop, thanks for the info. Do you know if the Self Test perfomed at initial startup checks the joystick calibration? Just wondering if operator might have his hand on joystick during the test. As I noted in 1st post no one here has experience with this model Cat and without a repair manual we're working in the dark. I think I'll advise customer to call the local Cat dealer- Wiese, or purchase a repair manual.

Thanks again,
Dino54

code 80 is throttle pot (VR1) out of range
i would try and run a learn on the handle first and see if that cures it
if not then you will need to replace the VR1

Note: if there is allot of play in the spring detent and the handle has excess play in travel direction and keeps beeping allot when in neutral position and will not stay calibrated you may want to consider just replacing the handle complete with a reman handle. Repairing these handle assy's has proven to be not so cost effective unless its a simple fix like a VR , knuckle repair/replacement or switches or the circuit board in the rocker button is very time consuming and labor will cost as much as a reman before its all said and done.

Hi Titus, the truck operator reported the code, I'll have customer double check with him. Our tech was there working on another truck and work-tested it for 1/2 hr. but it never coded out.
Thanks for the response, I'll report back with any new info.

Dino54

Hi Dino, I can't find. A code 80 fault code, do you think it might be a codes 8, code 8, just means the truck requires a service, I don't think that would have shut the truck down.

Regards Titus