Mileage Has Tanked Since Maintenance

Sounds like you are reporting two problems, so I'll comment on each:

1. Reduced mpg: Check your tire air pressure.
2. MFD battery SOC gauge doesn't move: Make your Prius READY, leave the car in P, and make the requested temp low enough so that the air conditioning compressor turns on and is cooling the interior. Sit there and watch the traction battery SOC gauge. Eventually the gauge should drop down to two red bars, at which time the engine should start to recharge the battery. If the gauge does not demonstrate this behavior then you should make this issue known to your dealer's service writer. It is not likely that anything would have been done during the 30K mile service that would adversely impact the SOC gauge.

 

The 2G SOC gauge has eight bars. From one to two bars, the color is red. From three to six bars, the color is blue. When seven or eight bars, the color is green.

So when you say 1 Blue bar, do you mean that you had three bars appear?

If you want to see seven or eight green bars you usually have to proceed downhill for a while so that the traction battery gets lots of charging. If you want to force charge the battery to satisfy yourself that it can charge up to 7 or 8 bars, make the Prius READY, shift to D, step on the brake pedal with your left foot so the car can't move, then floor the accelerator pedal with your right foot. The engine will rev up to around 2,500 rpm and if you watch the SOC gauge you will see it slowly move up.

I do not recommend that you do this for more than 40 seconds at a time as you are placing stress on the transaxle. Actually I don't recommend that you do this at all, unless you have a very strong need to see the SOC gauge move into the green.

 

Probably should check to see if the oil was overfilled or/and the wrong weight oil used??

 

I would take it straight back as soon as you can, I am sure they will fix it or tell you what has happened pretty quickly, they can see so much more than we can with their diagnostic equipment. Let us know what the outcome and goodluck.

 

The weight of oil shouldn't make much difference in summer temps. I tried running a heavy duty 15W-40 (Esso XD-3) one summer in my Prius. About a 2 mpg loss.

Check the tire pressure, and also check the oil level

 

You might also want to check if the rear brake shoes are dragging as a result of the service tech adjusting the brakes to tightly. I know that happened to me and mpg went down as the brake shoes were dragging.

 

Thanks, TP. That's another good point to keep in mind.

 

How to check it? Do I need to take the wheel off?

 

You don't have to take the wheel off, but you do have to jack up the rear wheel. With the parking brake off, it should spin very freely. If there is any dragging, that would be obvious

 

Jayman is correct. When I went in for service, I had on my punch list the fact that I had to push the parking brake to far down for the brakes to grab hold on a hill. The tech's solution was to tighten the rear shoes. Well that did create a drag which reduced my mileage about 15-20%. I brought it back to the dealer and they told me they reset the shoes and compensated by shortening the parking brake cable. Apparently that was the problem all along. Good luck.

 

With my FJ, the cable will stretch with use. About every 4 months, I have to give the adjuster collar a turn. The actual parking brake shoes (The FJ has rear disks, but a small cast drum for the parking brake) are fine

 

At the 15k and 30k service, they clean and adjust the rear drum brakes. See if your brakes feel better than thewy did before ie.. less travel. Mine lost mileage for a while after the service and the brakes felt better. Once they wear a little, the mileage should come back up to par