Mechanic say code there...My scanner say...Not there

A Gen 2 Prius has about a dozen different ECUs in it that all can set diagnostic codes. Later generations have even greater numbers of different ECUs, on the order of twice that many.

Many people have code scanners that are able to retrieve codes from at best the engine control module and maybe the brakes, because the scanners are lowest-common-denominator generic and pretty much all cars have engines and brakes. Codes in any of the other dozen or so computers in the Prius are invisible to them, and that explains the high volume of first posts on PriusChat from people saying "my car has warning lights on and there aren't any codes!"

Some people's scan tools don't even manage to read brake codes (even though pretty much all cars have brakes). That makes it fortunate that there's an alternate light-blink method for reading brake system codes that doesn't depend on any scan tool.

A person buying a new scan tool might want to check it, before it is really needed, to find out how many of the Prius ECUs it can actually get codes from. It can be used to pull codes from the car in the dark, or with a dark cover thrown over the solar sensor on the right side of the dash. The car will always have a B1421 code when that sensor is in the dark, so if the scan tool shows that code, at least you know it is able to talk to the A/C controller.

Flipping the handle on the service plug on the traction battery will create a P0A0D code (in Gen 1 the code was different), so if the scan tool shows that code then, it is able to talk to the HV ECU (a/k/a power management control ECU in Gen 3).

 

Do your own scan BEFORE taking it in.
IF......your scanner is not designed specifically for a Prius, then in likely will NOT be able to properly display codes for systems that are unique to the Prius......like the traction battery and the AC system.

 

That "long out of regular warranty" is part of the story. Things in cars long out of regular warranty start wearing out. The warranty extension on the actuator is to cover cases where a specific cause is why the actuator went bad, and they need the codes to confirm that. The extension is not a blanket "my sixteen year old part wore out I would like a new one please" program.

Even the codes that they do require can be set for other reasons, but they surely figured it's better to just cover it when the codes are present than to explain to customer B why it isn't covered if customer A's was covered with the same codes.