PRIUS 2007 RUNS MORE ON ICE, AND HAS GOT ONLY 25MPG

10-4.

 

How are you measuring the MPG? Just using the MFD?

 

Yeah, the mpg drop seems to just be a symptom. The strong clue is that the engine seems to be running more than usual.

One reason for that could be if the car isn't warming up properly? Which would cause the engine to run a lot. And one cause for slow warm-up could be engine coolant thermostat failing in the way that it doesn't seal good, and opens too soon, cooling too well.

You could try replacing the thermostat. When it's removed inspect it's gasket for fraying, brittleness. Also suspend both old and new ones in a pot (not touching the bottom), raise the temperature and observe the behavior of both. If you have appropriate thermometer you could clip inside pot, not opening/closing temps.

 

One more thing to consider on the hybrid battery--have you ever heard the cooling fan (grille in the back seat) come on?

If the battery state of charge appears steady and good, and there's no cooling fan operation, the hybrid battery is probably okay. How old is the 12V battery and what's its condition?

Is the ICE well-maintained? Changed plugs, PCV valve, clean throttle body and MAF, air filter? Perhaps it's running more because it's putting out reduced torque for some general reason not picked up yet by a sensor.

 

Whoa, hold on there, cowboy.

You said initially you had no lights on the dash, then you said a bit later the ABS light was on, now you produce a list of codes that would have certainly lit up the dash with a few lights. Can't help you if you don't give accurate info. But moving on, it is what it is.

Before you go diving into the battery assuming it is toast, consider other options.

Before anything else make sure you save the health check in techstream, so you can refer to it at a later date, especially after you've cleared the codes (see the end of my post).

The fortune cookie message for these codes are:

P3000 = HV Battery Malfunction
C1343 = Rear Hydraulic System RH Malfunction
C1344 = Rear Hydraulic System LH Malfunction
B1653 = Seat Position Airbag Sensor Circuit Malfunction
B1655 = Driver Side Seat Belt Buckle Switch Circuit Malfunction
B1821 = Open in Front Driver Side - Side Squib Circuit
B1271 = Combination meter ECU communications stop

As there are no other HV Battery ECU codes like P0A80 and (but not necessarily) P3011 - P3024, I would take a closer look at the other codes that you have. The P3000 can be set by the ABS ECU simply to tell the HV ECU it is having problems. Why is this important? Because the ABS ECU and the HV ECU work together to manage the regen capture. If the ABS is having a problem it tells the HV ECU and that in turn will disable the regen. (How are your brakes?)

So, I would look at the codes C1343/5 and see if you can resolve the ABS issue. Then work out what is wrong with the airbag and seatbelt sensor/switch respectively. The B1821 may point to a failed "clock spring" cable in the steering wheel (do all the steering wheel buttons work, out of interest?).

The B1271 I'd not worry about unless it comes up again, as that is a separate and possibly unrelated fault–if it really exists.

After attending to these things, clear all the codes with techstream and see what comes back. If you get the P3000 without any ABS codes, then I'd look further into the HV Battery. But again before you dive into pulling the battery from the car, you can perform this rudimentary test with TS as well as look at battery voltages and current while under load and discharge to see how the battery is performing.

Please keep us posted of your findings and progress.

Hope that helps.

 

Your symptoms exactly match those of a failing hybrid battery. Check out the Prolong Battery Charger/Discharger site. It may not be too late to add years to the life of your battery for just a few hundred dollars and a little time to install the required harness and do a few charge/discharge cycles. Absent that, you'll soon be seeing the check engine light/hybrid battery light. Do it now!

 

From several posters on here referring to the 2nd gen Prius having green bars alot was an indication of a bad cell or in the stages of failure. I don't think so as I get green pretty often especially around this time a year as I approached Winter as it's about 40-60 degrees and when I'm going downhill hills. In, July I rarely seen Green bars.

Posted via the PriusChat mobile app.

 

I agree. To add further, it's not the fact you have green bars that is bad, it is the rate at which it goes green and then the speed at which it drains to 1 blue (3 bars) or into purple then back up again to green. If you drive and have the battery in the "oscillate between '5-6' and '7-8' pattern" is not abnormal behaviour.

Apart from capturing energy on the down side of a hill, I regularly can get green bars (usually 7 bars) and can keep it there for quite a considerable time by DWB (driving without brakes) style of hypermiling on flat highway. This is achieved by long (or longer than usual) braking (from way out) on regen only to reduce speed for lights or other slower traffic. I am able to practice this technique even in heavier traffic without being a nuisance to other road users. I don't go slow or hold up other road users to do this.

Terrain and environment play big part in how this works, so take with a grain of salt. YMMV.

It is not only the CEL that is important. Any warning lights should be mentioned.

So are you saying the light came on and then you replaced the rear brake shoes as a fix? In that case you need to clear those codes, but if I recall correctly, you cannot just clear individual codes discretely, so save the current report, clear all the codes and see which codes come back.


[On an editorial note, there is an EDIT button (bottom left of any post you have made) you can use if you make a mistake, you don't have to start all over again creating multiple posts that say nothing.]

 

Here is what you need to watch for to determine if the hybrid battery is failing:
How do I know if my hybrid battery is failing? - Hybrid Automotive

There are warning signs before the red triangle appears. If you see them and act soon enough you can save a lot of $$$

 

The ABS will not go off on its own, you need to clear the code with your code reader (Do you use Techstream?)

Open circuit voltage test is not enough on its own. You need to follow that with a load test.

 

An H4 bulb will work as a one module load test. It will not work on a full pack. Here is how to do the test:
Prolong™ Battery Module Load Tester user guide - Hybrid Automotive

 

Jeff has pretty well answered your first question. The only way I know of testing the whole pack is to use Techstream while it is in the car. Back in Post #24 I linked to a rudimentary test procedure you can use. You can replay the recording of the charge/discharge test to look at individual voltages and observe how each behaves. You are looking for blocks that both charge quicker and discharge faster than its peers.