Attention Prius Owners, I believe I have discovered a previously unknown Mechanism of Low MPG.

There really isn't anything Toyota calls a "standard ECU relearn". There are a number of different procedures, some of which involve jumpers between CG and Tc or Ts and various amounts of time or other little dance steps, and it's a mark of wisdom to first know what any specific dance one is thinking of doing is really there for, before deciding when or whether to do it. The deets are in the repair manual, but of course there's not one place in it where they all are; each subsystem has its own section.

Toyota Service Information and Where To Find It | PriusChat

 

I noticed I get 60+ mpg city driving no more than 45mph by first driving the car for 20mins when the engine is warmed up I disconnect the 12v battery for a few mins and then when I drive it shows around 60mpg even in winter and I tried this a few times to confirm. Just tried uploading a pics of my mfd but it shows a error?? I’m new this is my first time using this site so sorry.

Anyone be kind enough to measure the rubber headlight bulb dust cap size please. Thanks I got flies in my headlight and the prices are to much so will just by universal ones but not sure if it’s 8” or 9”

 

So I have the 2003-2006 Toyota Factory Repair Manual now...where are the ECU reset procedures, because I can't find them anywhere?

 

Is there such a thing? I didn't think they bundled up years like that. What's the publication number?

As far as I know, when you go to TIS, you find your specific repair manual by model and year.

Toyota Service Information and Where To Find It | PriusChat

In what I've seen of those, each major subsystem (engine, hybrid system, brakes, steering, you name it) is its own major section, and procedures involving each ECU in the car are found in the section where that ECU belongs.

 

I have a gen2 prius, 2004 with 225k original traction battery.
Using torque... full or depleted, the traction battery cell pairs are all within 0.1v of each other..... I'm truly amazed. (used torque and setup 14 gauges showing min/max voltages of the 14 pairs (28 batteries).

I graphed pedal angle, ICE rpm, and battery SOC

When my battery SOC is near max, at 28-32deg pedal angle, the engine turns on. I repeated this multiple times on flat, slight incline, slight decline.
The 30deg pedal angle has been that way during my ownership (30k-225k).

Currently I drive 30miles freeway, 55-75mph every morning... coming home varies, but typically 40-65mph.

So based on what I can read, I'm in "weak ev" mode...

Side note:
Oh yeah.. I recently decided to check my 12V battery in the morning (car in garage).. uh oh. 11.0v
I turn on the headlights... 10.9... 10.8.... 10.7....10.6...10.5...(less than 2 minutes total).. I stopped there.
Put it on smart charger for a day.. checked voltage. 11.4. heh.
Optima yellowtop... it'll be 9 years old in May. I'm ok with that. Have a new battery coming next week.

 

Not trying to be a smartass but was this thread useful to anyone? I didn't read it all just a sample of a few posts.

I just thought that even if this is true, so what? If you need to disconnect your 12V battery what are you gonna do?

 

You can put a memory maintainer... you can get one that plugs into your ODB2 port, 12v port, or just connect a battery to your 12v jump point under the hood. That way when you unplug your 12v battery, you wont lose memory/settings

 

When I changed my 12 volt to a new one and ran my city mpg test I got a 7-8 mpg increase.
My old 12 volt was at 50k miles. Would be great if you can test this on your prius, mine is gone.

 

30v diff in two readings would likely point to trac batt temp starting and running, high temp texas here so when I leave work 5-6pm on a summer day the trak pak is 114-120 with the windows cracked and windshield sunblocker, most recently a 20'' strip of ceramic 80%(temu) tint on the front windshield, (30% front 25% rears) always, on those summer days just starting to hit the road, dr.prius app was all reds just discharge mode for the first 15-20 min of driving, ice kicking in at 3mph, anywho started just using the fan bypass on the dr.prius app as well as the as seen on tv "auto cool" lol totally needed as the ac is aged and a bit weak for tx heat everything helps !!! plus i sweat quickly and have a shaved head so no bueno, but yes take note of the temp diff of the two readings as well as the resistance

 

das what i been saying lol, once i changed my black bus bars that were pitted as well ev throttle improved greatly as well as resistance in the pack dropped !

 

I think you mean something else, 17L/100km is very bad. Translates to 13 MPG. A good amount in l/km is around 5L / 4.8 /4.0 or lower. (49 mpg)

 

I’ve disconnected it only twice, but I only notice a small drop. It gets better over time.
Since I’m in the EU I can force the car into EV mode if I wanted to. Maybe there’s a difference in US / EU versions. Mine is an 08 with no SKS. Your claim that most prii don’t have SKS is not totally true.
Other than that I just drive the car. Trying to completely debunk the car’s computers and complex coding is something only Toyota tech could do I think. But hands down for doing so.

I think that most people don’t even notice it. The car does whatever it wants to do haha.

Edit:
You claim that you can accelerate “aggressively” from 0 to 40mph on just electric power. That’s 64km/h. Now, how is that possible? If you do it “aggressively” (flooring or harsh acceleration), the engine comes on.
Now I’ve only encountered that twice. Once when I was accelerating very slowly behind a lorry. Managed to get up to 66 km/h.
The other time was after the light turned green when I approached it, so not from a full stop. Did somewhat the same thing.

But if you move off quick, how can you ever achieve that? Even in EV mode, (I have EU Prius) it turns off when going past the limit of 45 km/h or when requesting more power.
I find that hard to believe. I can try it on mine though.
The bat on mine is usually at the highest blue bar. Occasionally goes to a green status.

 

DarkAlaranth said: ↑
Hmmm. I have no data, but I suspect my Prius is in a High state, as it's getting 17Km/l (Worked out by distance travelled/liters refilled) which I believe is just under 40MPG

No, you're misreading: he says (and means I'm sure) 17 kms per liter, not liters per 100 kms.

It's a measure not normally used in North America, similar to miles per gallon. It converts to roughly 5.9 liters per 100 km, and 40 mpg US (as he says).

convert km per liter to liters per 100km - Google Search

convert km per liter to mpg us - Google Search

 

Aaah I see! Thanks for the clarification. I genuinely thought he meant the other thing. It’s roughly like how we say it here (Netherlands) (1 op 23) (1 on 23).
That explains it, since I’ve never really seen someone using that form.

 

km/L is used in Japan and South Africa and maybe other places. I prefer L/100 km as it is a linear scale. MPG and km/L are the inverse scales and are not linear.

 

Did not know that, thanks. I prefer l/100km too.