Prius Electronic Throttle Control System Malfunction

The Prius electronic accelerator pedal assembly



How the sensors work



Possible DTC's



Which DTC did your Prius set?

 

My engine seized, and the bottom end blew up, oil was everywhere. Is this normal?

No, something breaking or failing is not 'normal'. You might ask if it is a common failure, but it won't be 'normal'.

 

ETCS isn't the accel pedal. You probably have a dirty throttle
body and the motor is having trouble getting it open. Clean it,
open the gear housing and make sure everything's running
freely, and you should be good to go. Make sure the position
pot gets set exactly back where it originally was, or as close
to it as you can, as the system doesn't re-learn a new position.
.
_H*

 

One tip I can suggest is having a good DMM on hand with some alligator clips to adjust the TPS - I recall adjusting the TPS on a Lexus and Toyota calls for 2 feeler gauges - a .40mm and .85mm, and the procedure is to turn the TPS clockwise until you read infinity on the ohm scale and then see if there is continuity with the .40mm feeler gauge. However on a DBW car like the Prius, the DMM could save you if you took off the TPS without making matchmarks - just mount it and turn it clockwise as above until you get infinity.

 

(I suspect the poster was asking whether that diagnosis and recommended repair were reasonable.) Yes, they sound reasonable, but if you are concerned take the car to another dealer to get a second opinion and estimate. Any dealer should offer a warranty on the work they do, so if they are mistaken and must fix something else instead you should not have to pay extra. You certainly need to get it fixed, unless you are happy with an unusable car.

 

Whoops, that's what I get for multitasking and answering several emails at the same time. Your site has an excellent post-mortem on a Classic TB, most of which applies to the 2004-2009 model

The 2004 Prius TB



During the time I owned my Prius, 2004-2009, I cleaned the TB twice. First time dealer offered to do it, second time I did it. I never noticed any problems, but thought it would be a good idea to perform PM *before* having problems

On my FJ, I experiences MAF and TB deposits at a far greater rate than I ever did on the Prius. It's easy enough to clean the TB, so on the FJ I do it every fall and spring

Those living in climates that never get cold, say LA, Phoenix, Lost Wages, etc, may never have to clean their TB. Winter operation dumps a lot of oily moisture into the intake due to the PCV operation.

Combine oily sheen with EGR (The Prius and the FJ use VVT "tricks" to simulate an EGR valve) and you can have fairly heavy TB deposits

I should also point out the 2000 GMC Sierra I used to have, with Vortec 5.3, I had to clean the IAC pintle valve and passages in the TB at least once a year, if I wanted decent idle quality

 

I'm *so* glad the 1.5L does internal EGR via valve overlap, and
rather disappointed that the 2010 brings back traditional external
EGR which will doubtless be a perennial source of trouble just
like on any other car. Talk about "carbon footprint" ...
.
_H*

 

I think the "tricks" that Toyota use with VVT, eg in the 2004-2009 Prius and my FJ, to simulate EGR, will leave behind just as many deposits as a dedicated EGR valve system. At least if the deposits on the backside of my FJ TB are any indication

Having a separte EGR valve, with assorted plumbing and cooling, is one more thing to go wrong. Especially in a cold climate, the EGR valve will eventually gum up and stick, requireing cleaning