Bad combination meter - DIY worthy?

The combination of the meter and the rear hatch not opening suggests that you check your 12V auxiliary battery. This is the common element.

 

It's my understanding that repairing the combination meter circuit board takes less that a half hour of bench time. Something to do with the non-lead solder being used.

So if you can do board level maintenance like changing SMD chips, please try and tell us what you find out. The worst that happens is you destroy an already broken board.

It would be clearly illegal to change the odometer and/or misrepresent the proper value. But there is no license I'm aware of that is required to work on the odometer. It's just another electronic circuit board.

 

I'm guessing you're not eligible for Combination Meter Warranty Enhancement | PriusChat, right?

 

There is someone in the Bay Area that does repair on these boards, through Luscious Garage. An engineer checked out the board and found, IIRC, that the problem was related to a power up reset circuit that was not working. He replaced some component or other to get it working, but was not going to give out any public details about it, apparently. It should not be too difficult to spend a few hours looking into the power supply circuit, and replacing some surface mount caps perhaps, or an IC, or just reflow the solder. But it would require the right tools for such tiny components.

 

I would assume that if you replaced the odometer you'd have to report it as replaced and indicate that the mileage was not accurate. I would think that the law would take into account replacement of the odometer. Of course each state is going to have different rules, you'll need to check what MO says.

I'm curious what is related between the hatch & combo meter?

 

Luscious Garage gives a good technical explanation on this.

Luscious Garage | Blog | LG TV - Prius Dead Dashboard

Quoting from site--------------That said, what’s the explanation for the weird behaviors? It’s mostly confusion over vehicle speed: the speedo acts as a gateway to broadcast related information to other “body” ECUs on a dedicated communication bus called BEAN (Body Electrical Area Network) including those in charge of the power switch and the rear hatch.

 

No, but it is illegal to misrepresent the car's odometer reading. When the combination meter is replaced by the dealer, the new odometer is supposed to be programmed with the reading of the failed odometer.

If the combination meter is not reporting vehicle speed, then the hatch switch may not function. You wouldn't want the hatch lock to release if the vehicle speed was some value besides 0, for example. For the same reason, the POWER switch button will not respond if vehicle speed is some value other than zero - unless the switch is held down for more than three seconds to override that safety feature.

 

IIRC autobeyours repairs this meter, and the actual swap is straightforward.
The owner Steve has a sterling reputation so if you are happy with the price you are set.

He also has the part for sale on Ebay.

DIY Diassembly insructions

 

I think the risk of you breaking anything taking the dash apart yourself is pretty low. I took mine apart almost as far as you'll have to (except the top piece that goes across the whole dash) when I replaced the headunit. I don't think I've ever been less worried about breaking a tab. Everything seemed to come apart very easily if done the right way. So don't let that deter you.

My dealer let me keep driving my car while they waited for the part and I didn't get a chance to take it in for them to replace it until a couple weeks later. I ended up losing about 300 miles between them. Worst part is it messed will my mileage log.

 

1. I suggest you familiarize yourself with Missouri law regarding odometer replacement so that you don't have a problem there.
2. Once you satisfy yourself that you understand your obligations, then contact one of the Toyota dealers that sell parts over the web and see if you can order the combination meter with the odometer reading programmed in. For example,
AutoNation Toyota Gulf Freeway Parts | Toyota Parts Online - Genuine OEM Toyota Parts and Accessories - Houston, Texas

 

The used meters sold by autobeyours.com are picked to ~ match the old odometer reading. So long as the replacement meter shows at least as many miles as the old one, I would not worry about law breaking.

 

Yes the odometer can be altered with the correct equipment, but finding someone willing, and able to do this is the big problem.

John (Britprius)

 

Yep, that is why I mentioned autobeyours.com. They have an inventory of used meters of different odometer readings which lets them pick one that is close to the reading the customer has. Since old meters are not discounted, I would just take on faith that the owner Steve will replace or repair a bought meter that craps out early. His reputation is that good.

Luscious Garage thinks that all CMs will eventually die, but they also point out that almost all the failures they have seen are in taxis. So I personally would avoid buying a used CM that came out of a taxi, but otherwise would feel pretty confident buying used.

 

Question, since the odometer reading is a digital display, is the digital data stored on the instrument panel or internal to the ECU? My guess would be internal to the ECU.

 

It is stored in the combination meter, but it is no clear if it stored somewhere else as well. This I doubt but it is possible.

John (Britprius)