Latest Software Update Safety Recall Resulting in 8mpg less...

I used to not check tire pressure regularly before the Prius unless I suspected a low tire (you can usually tell by looking). Since PSI affects MPG on the Prius, I check it more regularly.

Oil dipsticks are crude gauges at best. I don't bother UNLESS I suspect an oil loss issue. You normally spot this problem when you realize the oil you recover is way less than what you just put in (even when you account for what's trapped in the filter media).

 

It has been about a month since my last service, and I took it back to the dealer, as they had specifically directed me, to check the tire pressure. I checked my tire pressure every week, and they were they were solid at 35 psi front and 33 psi back. This was also confirmed by the dealer today. The tires are not loosing pressure, so it is even more suspicious how they were all at 30 psi on the last service, when the dealer sets and maintains the pressure in my tires, and they didn't change at all in the last month.

Even with the tires at proper inflation (over the last month), I have been getting less than 40 MPG on two tanks... tire pressure wasn't it. They actually got about the same average as when they were all at 30 psi, so I am not sure if the read of the psi at the last service was correct since it should have gotten better millage with the higher tire pressure. They did a full health check and it passed everything.

So the car "officially" gets under 40 MPG (not meeting mileage specs) , and still passes all mechanical checks and diagnostics. I was (once again) told to file another claim with Toyota, but it was just going to go back to the dealer's customer relations person, so I talked with her directly. After discussing the symptoms with her and the service manager on my "in city" driving and my mileage records, they are escalating it to the Regional District Service and Parts Manager DSPM), who can supposedly come to San Diego to inspect my car and drive it.

No one in the dealership will go in the car with me to see the issues, which are blatantly obvious when driving in the city and watching the MPG calculator. EV mode in the city is not working consistently or correctly. They say they believe me, but it one be nice is someone (anyone) there that would go with me to verify it, and directly tell Toyota Corp.

My wife's 2011 still works fine, and my car is the only one that has the issues no matter which of us drives it.

 

I am also curious what ever happened to the other people that had this issue. I came in on this discussion on Page 10 and it is now on page 19. I have seen some references on other web sites, but I don't see much on any successes or failure's in dealing with the issue. Has anyone made progress, or seen a continued gradual loss in MPG since the recall (especially in city driving)?

 

I run 42 psi all around.

 

"Learning driving habits " How can the prius learn our driving habits?

 

The car has a 'fuel trim' table maintained in the control computers based upon past operation. But when the 12V voltage is removed for about a minute, the computers are reset and lose the 'learned' values. It reverts to the OEM table as it reconstructs the trim specific to your car. The symptom is changing a 12V battery leads to lower initial mileage until the car re-learns the optimum fuel-trim.

Bob Wilson

 

I have updated the software and changed the brake pump as per Toyota recall , here at Toyota dealer in Jordan , but I have'nt noticed any change in fuel consumption. There are other things affect Mpg rate , beside those mentioned above. Check your spark plugs, heater/AC, change in gas octane etc.

 

'Nother reason to do something like this when disconnecting the 12 volt:

 

Is that a JumpBox plugged into the OBDII port???

 

Yes. The orange cable has obd plug with just the power pins.

 

Are the power pins on the port always "On", even with the car off?

 

Yes. That's the express purpose of that cord, to act as a memory saver. It has an indicator light that glows red, whenever it has voltage, either from the port or the jump pack. That way you have confirmation beforehand.

 

From an internet search:
"OBD-2 connector must have pins 4, 5 for ground connections and pin 16 for 12 volt power supply from the vehicle battery."
Can pin 5 (Signal Ground) be eliminated and just use Pin 4 (Chassis Ground) and Pin 16 (Battery +)?
Which pins are used on your connector?

- Learn something new every day -

 

I'll take a pic and post when I can.

Clore makes one; mines by someone else, I forget. United something? They're pretty common.

 

Pic of obd connector:

 

Nifty! Does that circuit trickle all the ECUs in the car or is there only one main unit that holds all the driving history?

 

Thanks! Pins 4, 5, and 16...

 

Yes. From memory, I think the limit is supposed to be 1 A but it is usually fused for something more. The Wiki has a good summary.

Bob Wilson

 

Not sure how it works, but nothing get's lost. You could alternately hook a low amperage charger at the jump point; I've done that in the past. But I finally broke down and found one of these cords, very handy. Just ensure your jump pack has a 12 volt outlet.

I'm replacing the battery on my jump pack btw. Bit of an eye opener, opening up the case. Suitable batteries are available, for around $50.

 

I am a little dumbfounded. I just had my appointment with the Toyota Corporate Regional District Service and Parts Manager (DSPM), and they did another health check, checked the tires (which were still fine without having to fill them), and then we went out for a drive with one of the mechanics and a computer to read GPS and gas usage. We also did a trip set "B" to also monitor what the car thought the stats were. My last tank got 36 MPG and the current tank was running at about 37-38, so I was 100% confident that this test would clearly show the problem. I gave them all of my mileage records which clearly shows the problem.

The drive test was a reasonable 11 mile city drive (typical of what I do) and the mechanic that drove the car, drove similar to me (very slightly more aggressive on acceleration and breaking as I coast and speed up slower). I have no issues with their test, or how they did it..

While it didn't always do it, we were able to see that even decelerating with a warm engine and full battery and/or breaking to a stop, the motor stayed on for a few seconds after we came to a complete stop and did not go into EV Mode, other times EV mode came on right away.

The first 4-5 miles (the car was already warm when we started) was showing below 30 MPG, and then it started rising steadily and finished the drive at a "car calculated" MPG or 54.4 at 22 MPH, and the GPS/Computer showed 49.4 at 21 mph. That means for the rest of the test we were getting extremely high millage. I don't understand it at all, as I have had the last several thousand miles at under 40 MPG (including that morning when I tested it before I went in). I would love to get that millage, and the car displayed 54.4 MPG which is higher than I had gotten on the car "ever" (although it was 11 miles and not a full tank)

So my car is well within specs and based on the test drive, it is running in near perfect conditions to get that mileage, and my case is now closed.

The difference was that the mechanic drove instead of me, but as I have stated many times before, that when I drive my wife's 2011 I get the same high millage as she does, and when she drives my car she gets the same lower millage. I asked if I could drive after they did the test, and they said the computer had already shown the car is within specs (near perfect).

The only anomalies. After their pre-test drive testing my fuel gage showed full (it was down a notch when I took it in), and I have gone another 13 miles and it is still showing full. It should clearly be down at least a notch. The other trip set "A" only improved 1.4 MPG, when mathematically it should have raised it more than 2.0 MPG (although the GPS did show a huge discrepancy between the real and car calculated MPG which may account for some of the cars calculations). They did another health check (not sure if there was anything else) before the drive.

He was not aware of the problem or Toyota knowing about the problem in this thread as well as this same issue documented on other sites. I thought this test would be a slam dunk showing it was a problem, and instead I have one of the highest functioning Priuses based on the 11 mile test and acceptable mileage ranges. At this point I am stuck, and I am interested to see what happens through the rest of this tank