Bad trans fixed itself?

For the pros on here, I have a good one. I have had a previous parasitic draw code with a sub code for the trans. I placed previous posts and we gave up on it, thinking we will eventually need to swap the trans. No issues, she runs good, but she would always throw that code, usually at slow speeds. For 18 months now, we have driven the car daily, constantly resetting the code. And as everyone knows, that code disables cruise control and stops the car from restarting. Instead of using Techstream, we discovered that a generic code reader could reset the system, even though it could not read the Prius code. As she continued to pop the code; it got so bad, (10 miles) we kept clearing the code while driving to retain cruise control. Again, 18 months, and now 2600 miles (she’s around 350,000 miles; new Michelins at 298,000 and Michelins are half worn) since the last reset, the trans has ???”burned”??? whatever was creating the parasitic draw in the trans. Keep in mind, the car never ran strange, ran bad, no noises, etc. just threw the parasitic code; sub code for the trans. Is it possible that whatever was causing the parasitic draw code (short) in the trans, burned up? This truly is an amazing car and has lived a rough life as a retired cops right foot commuter car. Always well maintained, but she’s been beaten on since 2004 with 5 miles pulling out of the dealership. I’d love to hear an experts assessment.

 

AND she’s getting 54.2mpg highway. Last tank 550 miles when the gas gauge started flashing. 10 gallons. Thank you UREMCO for those kick nice person injectors. THEY made her achieve the gas mileage, better than when she was new. Likes oil, 1 1/2 quarts every 5000 miles.

 

Sorry for the bad terminology. ISOLATION FAULT CODE, sub code for the trans.

 

Thank you P0AA6 with a techstream sub code pointing to the trans. I’ve owned her since new. Toyota Trans fluid change every 100000. Nothing in the fluid, always been well maintained but ALWAYS beaten on until recently. We have a spare trans ready, paid 90 bucks, but it hasn’t thrown the code for 2600 miles, versus every 10 miles. On thing. Retirement brought on a new easy going driver. 10 over the limited is good for me now. Car use to get horrible mileage until the UREMCO injector swap around 298000 as well. She’s 55MPG every tank since then. Every gen2 I swap the injectors gets over 50mpg. I would really like to know, whatever was frying, shorting out, freed itself clean?

 

When we determined it was the trans. (18 months ago) We performed the Toyota manual test with an insulation test multimeter. I can’t remember which motor it determined. But the test concluded it was the electric motor that had the isolation issue, but she never ran anything but good. I haven’t taken it apart again to re test. But since we’re at 3200 miles since the last reset, we’re leaving it alone. I can only assume, whatever was causing the leak burnt away? Or it’s about to blow in traditional noise and fireworks. We are somewhat baffled, but this car has amazed us over the last 19 years. In town, we’re down to 53 mpg.

 

We used this tester.