Folks, I have an 05 Prius and lately it's developed an issue. The car has the red triangle on, check engine light on, and under acceleration it seems to hesitate. The code that show up on the scanner is: P0A78/285: Open or GND short in motor inverter fail (MFIV) signal circuit. Possible trouble area (this is from the Prius diagnostic manual): - Wire harness or connector -w/ converter inverter assembly This does look like the inverter is shot. Can someone comment on experience with this issue? I know there is TSB on this specific issue (EG025-05) and it says to replace the inverter. Anyway, thanks for all and any help.
[/i] I assume this is continuous from starting, not after long driving /overheating which is a different issue. I would be curious and after turning off/ disconnecting the high voltage, (pulling main fuse plug in rear of car; see tech manual), would take off the inverter cover to see if there is any obvious burn/dark burning plastic areas around the inverter( and the wiring that supports it) . Note ; I am not a professional and have taken off the cover once, really didn't seem to be big deal, although I was careful not to touch anything. Have fun....
It should still be under the hybrid system warranty, in which case you don't want to fool with it yourself lest you void that warranty (or get killed).
Warranty is based on many fine legal lines drawn in Toyota favor. The Prius is basic toss away after warranty goes.!! Certain componets fall under a limited oem mfg warranty . I doubt that the inverter, trac battery, and transaxle are covered after certain specific time period and mileage odo achievement.
"The Prius is basic toss away after warranty goes.!" Dang! So now I have to throw away my 2004. Can I get my Jeep Cherokee back? Oh man, that 15 MPG and the electrical fires were sweet.
On a more serious note, before changing the inverter, try this: CAUTION: Wear insulated gloves before performing the following operation. (a) Turn the power switch OFF. (b) Remove the service plug grip (see page HB-154). NOTICE: Turning the power switch ON (READY) with the service plug grip removed could cause malfunction. Therefore, never turn the power switch ON (READY) in this state. (c) Remove the inverter cover (see page HV-531). (d) Check the connection condition of the I9 and I10 inverter connectors. OK: Connectors have been connected securely and there is no poor connection. (e) Reinstall the inverter cover (see page HV-538). (f) Reinstall the service plug grip (see page HB-154). Even if the connector is properly mated (which most likely it is). I doubt that gold contacts are used on this connector. Seperate and reconnect the connectors, the wiping action may restore good contact. This is an input signal problem, so it may be repairable without replacing the inverter.
