How to use engine mode? Hybrid wont charge battery keeps going to 1 bar occasionally wont start.

Yeah all this can be very subjective folks are talking about driving around on electricity and all this kind of stuff. Once you get to the nitty gritty it's something pretty basic usually or you're an out lier and have internal hybrid synergy drive issues open short in trans motors etc . Extremely rare . These threads generally go 50 plus posts deep .

 

The first thing to check for a no start condition is the 12v battery.

 

^+1, Yep, I'd start with the 12V aux. battery - it's probably borderline. I'm assuming that there's no CEL since a Toyota technician looked at it? Obviously not a very good technician, because they didn't even check the 12V battery condition.

1. you can try jump starting the car.
2. pull out he 12V battery and take it down to any auto parts store for testing. It's located in rear passenger trunk panel.

Hope this helps..

If your 12V battery checks out OK; the instrument cluster on those old Prius sometimes doesn't light-up. To troubleshoot that, just put the car into gear and go. If the car moves; you'll be driving "blind", but everything else should be working. It's a bad power supply capacitor, so sometimes it just won't turn-on (instrument cluster). That won't throw a CEL either; so unless the technician sees it - they won't know that there's a problem.

 

Much depends on how the car is used. As you noted, regular - steady driving allows the car to keep the HV battery in the 5-8 bar range. There's "lots" of opportunity to do regenerative braking to help keep the battery topped up.

If you are in stop and go traffic, especially with the A/C running, then the battery will go down to 1 bat, and only run the engine enough to charge it to 2 bars.

I guess that Toyota engineers decided that they wouldn't "waste" gas by charging the battery more than absolutely necessary when the car isn't moving very much. (Any gas used divided by little to no distance traveled equals poor mpg, and the Prius is all about getting "max" mpg).

That said, as the HV battery ages and deteriorates, it will lose capacity and shift from "lots of bars" to "1 bar" more quickly.

Posted via the PriusChat mobile app.

 

As noted above, a hybrid won't go to Ready if the 12v battery is discharged. My experience is a Prius agm 12v battery will get very intermittent when it is used up. The easiest test is to remove it and take it to an auto supply for a free 12v load test.

If a 12v jump "starts" it you know it's the 12v battery causing the immediate problem. It does not take leaving a hatch light on to cause this if the 12v battery is bad. Jumping a Prius can damage it if jumping from another vehicle and the cables are reversed even for a second. The best way is with a 12v jump box with safety checking.




In almost all cases, a "low capacity" hybrid battery will still spin the engine to start it. If it can't you will get a code.

That does not mean a weak hybrid battery will have much capacity left. A sign of low capacity is the engine running at a traffic light to recharge the hybrid battery. A good hybrid battery can almost always run the car by itself at a traffic light for three to five minutes.

Bottom line - load check the 12v battery first. Second you may have a weak hybrid battery.

Jump starting a Prius gen2 from owners manual. It shows jumping from another car battery. Using a portable jump box is far safer. I keep one in both of our hybrids.