Strange MFD Behavior

[ekpolk]

Background: my car is an 04 Prius approaching 16k total miles. I recently bought it used; it's in outwardly great condition, and has shown no indications of serious problems at all. I have seen no warning lights displayed "in anger." Overall, car seems to run beautifully, and per my MFD, I'm averaging 48.0 mpg.

Except for two anomalies (to my eye, anyway). The first: my morning commute is ~10 miles, the first and last two miles are surface streets, the segment in the middle, freeway. Coming off the freeway, I approach a series of traffic signals, in a pretty high SOC (green or top blue). As I run between lights, keeping up with traffic, the ICE usually kicks on. As I lift off approaching the next red, the MFD says the ICE has shut off, just as it really should. But as I come to rest, I can still feel the ICE running, and maybe 5-15 sec later, it finally shuts off for real (unmistakeable, as sometimes, it's not very smooth doing so). Can anyone tell me why the MFD says the ICE is off ~200 yards and ~20-30 seconds before it really is?

Second one: again coming to a stop, but more randomly, maybe 1-2 out of 10 stops, despite being at a complete rest, foot securely on the brake, no doubt I'm not rolling at all, I still get yellow arrows that make it look as if the MGs are still moving the car forward. When this happens, it won't stop, unless I actually put the car in neutral or park, or shut down the hybrid system totally, of course. When this happens, again, the arrows only go dark, as they usually do (and as I would think they always should), if I select N or P; otherwise they just keep flowing until I start driving again.

I'm well inside wty, and the car generally functions as intended (pt A to pt B with efficiency and fun), but still, I'm really hoping my car doesn't have developing "neurological" (or perhaps psychiatric ) issues. Anybody got any thoughts or suggestions about what's going on here? TIA.

[efusco]

<div class='quotetop'>QUOTE(ekpolk @ Aug 14 2006, 07:21 AM) [snapback]302938[/snapback]</div>

Except for two anomalies (to my eye, anyway). The first: my morning commute is ~10 miles, the first and last two miles are surface streets, the segment in the middle, freeway. Coming off the freeway, I approach a series of traffic signals, in a pretty high SOC (green or top blue). As I run between lights, keeping up with traffic, the ICE usually kicks on. As I lift off approaching the next red, the MFD says the ICE has shut off, just as it really should. But as I come to rest, I can still feel the ICE running, and maybe 5-15 sec later, it finally shuts off for real (unmistakeable, as sometimes, it's not very smooth doing so). Can anyone tell me why the MFD says the ICE is off ~200 yards and ~20-30 seconds before it really is? [/b]

Normal behavior. The MFD does not show exactly what's happening..heck, it only shows 1 of the 2 MGs. More than likely, on that run b/w lights, you're not exceeding 34mph, if you don't speed up over 34mph it's less likely that you'll go back into stealth (ICE shut off). What is happening is that the ICE is still spinning, via MG1, but probably not burning any gas. If, once stopped, you firmly press down the brake it should shut off in ~5-7 seconds. Alternatively, you can consider getting an EV button to force it off before you come to a complete stop.

again coming to a stop, but more randomly, maybe 1-2 out of 10 stops, despite being at a complete rest, foot securely on the brake, no doubt I'm not rolling at all, I still get yellow arrows that make it look as if the MGs are still moving the car forward. When this happens, it won't stop, unless I actually put the car in neutral or park, or shut down the hybrid system totally, of course. When this happens, again, the arrows only go dark, as they usually do (and as I would think they always should), if I select N or P; otherwise they just keep flowing until I start driving again.
[/b]

You're just not pressing the brake firmly enough...it takes pretty firm pressure and those arrows go away. What's happeing is that you've got a little more flow from battery to MG2 to wheels than the car is happy with so it shows that there is some flow. Again, totally normal.

[qbee42]

I drive a 2006, so there may be some differences, but I'll have a go at it. There are many occasions when the ICE is spun without consuming fuel, or in other words, spun by the electric motors. One example is when the SOC is high and the computer needs to burn off extra power to protect the battery. It also happens at speeds in the mid forties and above, when the ICE has to spin due to the gearing of the PSD.

When stopped, the Prius simulates "normal" automatic transmission creep by applying a small amount of torque from the electric motors, depending on the pressure applied to the break pedal. This may account for the yellow arrows. Normally, you would expect the arrows to go away when firm pressure is applied, but I don't know for the 2004.

Tom

[ekpolk]

Thanks guys, I appreciate the quick responses. Perhaps I just need to softly chant, “It’s a Toyota, it’s a Toyota, …” for a while to help myself relax a little. Glad to know that things are OK. So, Dr. Fusco, what would be the proper term for hypochondriasis, when it applies to a motor vehicle instead of one’s body???

[efusco]

<div class='quotetop'>QUOTE(ekpolk @ Aug 14 2006, 08:03 AM) [snapback]302943[/snapback]</div>

Thanks guys, I appreciate the quick responses. Perhaps I just need to softly chant, "It's a Toyota, it's a Toyota, …" for a while to help myself relax a little. Glad to know that things are OK. So, Dr. Fusco, what would be the proper term for hypochondriasis, when it applies to a motor vehicle instead of one's body??? [/b]

hypocardriasis?

[seasidetraveler]

Will somebody PLEASE tell me what MFD is??? I keep asking and no one tells me! I know it's the display, but what does the acronym mean?

[Tideland Prius]

mother....

just kidding

multi-function display.