The check engine light is either red or orange. With a motor symbol in the middle. It flashes in a sequence to state the code.
The propane filter should be inline from the coupler to vaporizer. A secondary filter is in the vaporizer as well. You may have a blown high pressure seat internal in the vaporizer. We just replace the assembly vs a kit. It allows to much fuel and kills the motor. All parts are online @ toyota if you need oem.
Make sure the spark stays while cranking. After it quits. Maybe a bad distributor. Oem parts are 2 yr warranty From toyota. If you have spark then fuel. Take a pic of the dash and post it. Thanks

There is a dash warning light but we cannot find any reference to it or what it means. It is a circle with hash marks horizontal through it, there is a down arrow wide at the base of the arrow (top of the circle). The hours are 5810. The lift was looked at by a mechanic but he told us nothing other than it needs a new distributor which was replaced but now having the same issue. Currently trying to find out what fuel filter to put on this unit, we did not get a manual with it. If it sounds like we are clueless, we kind of are, but the only game in town charged us $800 for 25 minutes to tell us we could fix the problem ourselves on a prior issue.

There should be stored codes when the laptop is hooked up. Can monitor fuel psi and what is happening. Would have to know specifics for that code. No check engine lights or dash codes?

To our knowledge the fuel filters haven't been changed. This was purchased off lease from a big box retailer. It is LPG.

The dealer should have tested the components with the laptop and engine software. You can see every component working. The MIL light on at all? It should have some sort of component failure code. Hrs on unit, has the fuel filters been changed? LPG? Or gasoline?