Only 38mpg and lights on the dash related?

Hey everybody, I've been reading a lot on this forum the last month or two and only signed up recently after buying my first Prius so this is my first post.

The lights on the dash (ABS, Traction Control, Brake light) seem to come on for a lot of reasons from what I've read, but the one fed me by the previous owner with documentation to prove it was an alignment job at a tire shop that didn't have the Toyota ABS reset tool. I have to believe them I guess.

My 2010 Prius IV with 105,000 miles has those three dash lights on and it doesn't seem to affect operation at all except for two things that are happening at the same time, either by coincidence or not:

1) The cruise control refuses to turn on, or turns on and instantly turns off.
2) The MPG seems substantially lower than what everybody else here is getting.

With both I've already checked all the fuses under the hood and they're all fine. It drives great in all conditions, plenty of power, HV battery seemingly in good condition. Went to Advance Auto Parts and it showed no engine codes, but they can't read the ABS codes.

I'd read from a few people on this forum that the 12v battery might cause this so I changed the original 12v battery out 2 weeks ago for a new Optima Yellow Top. The original battery had lasted 8 years in Florida, which is a miracle on its own, and it was losing enough charge to need a jump after 2 days.

Seemingly no difference in MPG after the new Optima, but the MPG has gradually increased since we've owned the car, probably from getting used to "drive it like a Prius." When we first bought it we were only getting 34mpg. Now it's up to 38.7mpg as of this writing with maybe 600 miles on the car since owning it.

I'm the kind of guy who already coasts a lot, lifts off the gas way before stoplights, and exceeds the mpg ratings of my other cars, so I don't think this is a user error issue. I've tried pulse and glide plenty as well.

Having read the "insert paper clip into OBD2 connector in ready mode" trick to reset the lights on this forum many times, I tried that a dozen times or so, including various permutations of hitting the brake 8 times in 5 seconds. Nothing changed. I'm convinced it only works on Prius Gen2, not Gen3, unless somebody with a Gen3 can say otherwise.

I drove a friend's 2012 Prius IV for the same 2 mile loop I do with stop and go traffic to the grocery store. His has about 100,000 miles on it and regularly gets 46-50mpg. A few takeaways:

1) It allowed me to go up to 35mph using only the electric motor. Mine never gets above 25mph before doing that. Because of that I was operating all-electric for much longer.

2) His HV battery indicator remained near the top that entire drive. Our car would have already dropped the HV battery to 2 bars left by the end of that driving loop.

3) The brakes on his car were much touchier than mine. Maybe just different pads, but maybe his car the pads are farther away from the discs, less drag etc. I've lifted the rear of my car and they don't seem to drag much. With a decent shove the wheels will rotate 4 times before stopping.

4) The tire sidewalls on his car seemed far stiffer and squarer than ours. I noticed the sidewalls on our low-rolling-resistance tires bulge more than they probably should, so I aired them up to 40-42psi. They still have more bulge to them than what I think they should. Makes me wonder if the car had been left in a lot for a long time and the tires deflated to 20psi or lower and the car was driven like that and flexed the sidewalls to the point where they're not stiff anymore. That would be a big increase to rolling resistance, but I don't know how much mpg it costs.

I hopped out of his car having gotten 46mpg on that trip. I would have done only 34-35mpg in my car on that same short trip.

So needless to say I want the lights off the dash regardless, but they may not be a clue of why our Prius gets such low mpg. I don't want to go to a dealer unless I absolutely have to. I've had old cars for the last 25 years and I only very rarely don't fix everything myself. I'm talking full engine rebuilds in my garage. I'll take it to an independent mechanic if necessary but don't know how common it is for them to have Toyota-specific ABS reader and reset tools. I found a $160 Toyota ABS scan tool on ebay that seems like it might be worth the investment but I can't verify it works so hesitant to buy it.

So ideas? Thanks!

 

I'll write a TLDR version too:

2010 Prius IV, 105,000 miles

Problem:
1) I have the ABS, Traction, Brake lights on (bought car like this)
2) Cruise control doesn't work
3) I get only 38mpg

Checks:

1) Changed 12v battery for new,
2) Checked it has no codes,
3) Drive it smoothly
4) Only real visible cause is tires seem to have really flexible, bulgy sidewalls compared to friend's car at same inflation pressure
5) Drove friend's 2012 Prius and got 46 mpg doing the same things I do. His car will run electric motor up to 35mph vs my car only doing 25mph before turning on engine.

 

Thanks for your advice. Does that mean I should see the charge indicator increase when I hit the brakes? When I lift off the gas it starts charging and when I put it in B mode it charges substantially more, but yeah I haven't I seen the charge increase when I hit the brakes.

 

I appreciate the advice but your tone makes you seem more interested in teaching me a lesson than helping.

1) I've been fixing cars for 25 years. This is not a problem.

2) Been driving 25 years, so yes I know this basic information.

3) I put a TLDR right after the post for people who thought it was too long. You not reading explains the other parts of your comment.

 

I appreciate the concurring opinion on that. The theory really does make sense. I guess I'll be feeling around on the wheel speed sensors to see if there's an issue. I'll definitely check out that ABS reader from Harbor Freight that Tankuong suggested if it can do all the resets too.

 

Yes the lights are illuminated all the time. Immediately on startup and never turning off. Will hopefully have that Harbor Freight Zurich scan tool in hand today.

 

To avoid dealer fees and since i wanted the tool for other cars anyway, I got the Zurich ZR11 which is capable of scanning and resetting OBDII and ABS codes.

I got codes c1203 (ECM communication circuit malfunction) and c1345 (Linear Solenoid Valve Offset Learning Undone) and tried doing a reset that I found buried in another thread involving the #12 TS pin to CG on the OBDII port instead of the #13 TC pin to CG. On my car the TS and CG pins are both the 5th from the right. I did this as a combination of threads I read on 4Runners and Priuses since this information was not all in one place.

1: Put the car on flat ground (Of all the jumper wire tutorials I saw on Priuses, this was mentioned in just one of them yet seems absolutely critical).
2: Put 2 wires (or paperclips) in the TS and CG pin holes.
3: Push power button twice on Prius dash without pressing brake. You want "on" not "ready"
4: Tap the wires/paperclip together 4 times in 8 seconds. Lights on dash should start flashing in odd patterns. Let that go on for maybe 10 seconds.
5: Turn off car
6: Connect those two wires or paperclips together
7: Push power button twice on dash without pressing brake. Lights will flash and you'll hear ABS actuator depressing pistons in sequence. Wait until it stops pressing ABS pistons (you'll hear it) and light pattern changes on dash.
8: Push power button to turn off car
9: Start car normally and drive car straight for 25mph or more for at least 10 seconds.

The good: Doing this I managed to get 1203 to go away, which previously had not cleared on its own with the Zurich scantool without coming back immediately.

The bad: The dash lights are still there, c1345 refuses to go away and I'm pretty sure the regenerative braking still isn't working (it appears I've never experienced it with this car in its first 600 miles with me).

So yeah I'm hoping there's some other trick that's a modified version of the TC/CG pin ground that may fix the rest.

I've also read this points toward the ABS solenoid system or the Yaw sensor, but hell I'm sure it could be more. Ideas? Thanks!

 

Yeah I can see your rationale there but this is based off of a few threads I've read where somebody came in with the same issues I have, did that jumper procedure I outlined, and their car ended up having all problems go away at that point, so I had to try it.

Interestingly after doing that procedure I got my cruise control working now, so I've got that going for me.

I'm interested in that Techstream setup but I guess I have to buy more stuff to set that up. I might have access to a windows laptop but everything I have is macs. Is there a usable version of Techstream that doesn't cost $55 for 48 hours just to access the software?

 

I appreciate the advice. Thankfully what I did solved at least three of the problems with the car, which is the goal here.

I'm pretty used to solving things with Mr. Google and car forums because it's worked for me for quite a long time when repair manuals were either vague to the point of being pointless or seriously underexplained the wide implications of a single trouble code. People's personal experience repairing things tends to be more nuanced and real-world compared to the manual. It's just a bit of a learning curve here where the self-repair community is much less robust than for other cars I've owned.

Back to the problem at hand: Which "the manual" are you talking about? There are quite a few available. I'm new to this car and community so I don't know the common inside info. There are quite a few cars I can rebuild with my eyes closed but this isn't one of them yet since I've only had it for 2 months, but I'm getting there.