My 2008 Highlander Hybrid is driving me crazy… anyone have advice?

Toyota Truck, SUV and Vans Forum Toyota Highlander
1

I bought my 2008 Highlander Hybrid for $13k back in September 2023. It’s my second car after my first one, a Chevy Aveo, completely gave out on me. I’ve taken it to Toyota three times already, and they keep telling me nothing is wrong… but I keep having the same issue.

I’ll be driving, then out of nowhere, I lose all acceleration, and the screen says “Check Hybrid System.” The first time it happened, I switched to econ mode and barely made it home. Took it to Toyota, and they said they couldn’t find anything wrong—no codes, no warning lights when they checked.

A week later, I try to leave for work—same thing. “Check Hybrid System” comes up, and I have no acceleration. I was in a rush, so I pulled the battery cable for a few minutes, put it back, and it ran fine. Later that same day, driving home, boom—same issue. I had to stop in the middle of the road and do the battery cable trick again.

Towed it to Toyota again, and once again, they scanned it and found nothing. No codes. They say there’s nothing they can do. I drove it home, and for about a week, no problems.

Then yesterday, as I’m pulling into my parking spot—“Check Hybrid System” again. This time, I didn’t reset anything. I left the warning up and called a tow truck. Surely, Toyota will see something now, right? Nope. They call me today and say everything is working fine.

I’m seriously losing my mind. How am I supposed to fix a car that keeps breaking but leaves no trace of the problem? I just want a car that works. I feel like I got scammed out of $13k. My dad gave me a CAA membership for Christmas, and I’ve already burned through almost all my free tows, and it’s only January.

I had a different car before this that cost me $2,000 in diagnostic fees before it ended up in the scrapyard. This feels like the same nightmare all over again. If anyone has any ideas or has dealt with this before, I would really appreciate any advice. I honestly feel like giving up.

2

Get a Bluetooth OBD2 scanner and check for codes before resetting or turning off the car.

Or if it happens again, drive straight to a parts store and have them scan it. You need to give the mechanic something to go off of. Hope you get it sorted!

3

@Tilden
I actually have one. Scanned it right before towing it last time, and it showed nothing—DTC: 0. So frustrating.

4

Zeke said:
@Tilden
I actually have one. Scanned it right before towing it last time, and it showed nothing—DTC: 0. So frustrating.

Yeah, regular OBD2 scanners don’t always catch hybrid-specific codes.

You might want to try the Dr. Prius app. It works better for hybrid diagnostics.

Also, some independent mechanics have way better scanners than the cheap ones we can buy. They can pull real-time data and catch more details.

Might be worth calling around and seeing if a local shop is willing to take a look. No point in going back to Toyota if they just keep telling you nothing is wrong.

5

@Tilden
That sounds like my next move. Appreciate the advice!

6

Zeke said:
@Tilden
That sounds like my next move. Appreciate the advice!

Are you comfortable with tech stuff?

If you are, get an OBD scanner that works with Toyota Techstream from AliExpress (some come with older copies of the software). Install it on an old laptop and leave it in your car.

It’ll give you access to Toyota’s full diagnostics and should be able to tell you what’s wrong. Costs about $25 and a little time to set up, but it might finally get you some answers.

7

Check your spark plugs.

We had this same issue after 15 years of owning our Highlander. Should’ve replaced them sooner! It’s been a great car otherwise.

8

This might be a dumb question, but have you replaced the 12V battery? A weak battery can make all the electronics go crazy.

9

Berlin said:
This might be a dumb question, but have you replaced the 12V battery? A weak battery can make all the electronics go crazy.

Hybrids don’t have alternators, so the 12V battery is even more important.

10

@Marlow
Didn’t know that! Good to learn something new.

11

Berlin said:
@Marlow
Didn’t know that! Good to learn something new.

Yep, hybrids also don’t have a traditional starter or power steering fluid. They use electric power steering instead.

12

Does it struggle to reverse? If so, that could mean the hybrid battery is failing.

13

Man, this sounds like a nightmare. I’m sorry you’re dealing with this.

14

How many miles are on it? Hybrid systems are really complicated—some say they combine the worst parts of gas and electric cars. That thing is 17 years old now. Even regular gas cars don’t always last 20 years.

15

@harry
It has 221k miles. Toyota tested the hybrid battery and said it’s good.

16

Zeke said:
@harry
It has 221k miles. Toyota tested the hybrid battery and said it’s good.

That’s a lot of miles. The hybrid battery is just one piece of the puzzle, though. You’ve got controllers, sensors, wiring, and all sorts of other things that can go bad. Electrical problems are the worst to track down.

17

Zeke said:
@harry
It has 221k miles. Toyota tested the hybrid battery and said it’s good.

If you can get it running reliably for a little while, maybe think about trading it in before it leaves you stranded again.

18

@harry
I’d love to, but it needs some work before it can pass inspection. Not sure if that affects its trade-in value.

19

Zeke said:
@harry
I’d love to, but it needs some work before it can pass inspection. Not sure if that affects its trade-in value.

You’d be surprised. Some dealers will still take it, especially if they plan to auction it. Might be worth getting a quote and seeing what they offer.