combination meter repair - DIY

That's it.

Doug,
I'm sorry that you feel like I "used" the group for my personal gain. I contributed a lot of good information to the thread which helped narrow down the problem and I thought I made it clear in post #38 what my intentions were for the repair but I will say it again. Replace all 3 of the surface mount caps and the voltage reg ic and it will be fixed. If you want to upgrade the 5V filter to match specs with the new Toyota meter that will be even better (see my post #34). It's not a complicated repair but it does take a bit of practice if your not already proficient at board level repairs. PM me if you need more information, I'm always happy to help.

Matt

 

Sorry. It was not clear to me in your post #38 that replacing the three caps and voltage reg ic, in fact, turned out to fix the problem, Matt. Thank you for clearing that up and I do appreciate your and others efforts on coming up with a practical solution.

For those, like me, who have searched for a way to fix it ourselves and are capable of doing so, can you provide a concise list (maybe with a link like you did in post #43) of the three caps and voltage reg ic that worked for the repair?

Thanks again,

Cary

 

[QUOTE

Work the caps side to side until they break loose, always being careful not to over do it and damage the pads. Then clean up the pads with a braid and re tin them. Is there another way that would work better? Thanks[/QUOTE]

Correct! That's the way to remove SM caps. You know what your doing.
And Mouser sells a line of Panasonic low ESR caps. I always try to replace
SM caps with regular caps size permitting with slightly higher voltage rating.
Then when done clean the board with Q Tips and acetone. Looks brand new.

 

While we may not get this to a step-by-step DIY status (links to the capacitors, anyone?), at least I can add some pearls of wisdom to the removal and replacement of the combo meter. I used a YouTube video at

.
My clear plastic bezel was not so clear anymore due to the previous owner using an abrasive cleaner. So I buffed out the scratches with polishing compound and a drill in under a minute. If you have a headlight cleaning kit, you're good to go with that.

MATERIALS

AFTER YOU GET THE COMBO METER OUT

REMOVE THE CLEAR BEZEL AND CLEAN THE MIRROR

GENTLY CLEAN THE PLASTIC BEZEL WITH POLISHING COMPOUND

WHAT A DIFFERENCE THIS MADE!

 

Thank you TexasNative for the pictures, Video link, and I too agree that it would be extremely helpful to actually have a guide to do the repair. For a while now, I have already repaired a few monitors of failed capacitors that were trashed and made a nice return on functional equipment but point being is, the soldering knowledge is present. I simply would appreciate if this information was available for the circuit board on the combination meter.

I happen to have a 2005 Prius that has suffered with this issue of the combination meter whenever temperatures would drop under 60F. Oddly enough, I would have moments with 10 degrees F and it would work where as today a nice 60 degrees F at night left me with a blank dash. By now I am used to it, but it sucks. I love DIY and the biggest issue is risking time and money to find the solution in the ever growing world.

I stumbled across this thread a year ago but today seems more information is present and my slight annoyment with my blank combination meter tonight sparked interest again in the issue. Can anyone kindly show a picture (even a video) of what caps/parts need to be replaced?

We live in the year of 2016 where an iPhone 4/5 is handed down to 6th graders because they cost around $50 and nearly everyone has a smartphone. Since we are in such a time, information on repairing and DIY is exploding within the past year. Look at Youtube and Luis Rossman who basically shows apple motherboard repairs on live start to finish procedures. Why is this 13 year old combination meter issue still without a "exact" thread solution? A successful business can still make profit even if information is shared. The way to make money in this society is not hiding information but marketing better. If a company has to hide info to survive, they are quickly entering a time of failure because leaked info is easier day by day with technology growth. Anyways enough ranting, I simply would like to request some help as well and may be willing to pitch back a professional video recording of the process if given the chance

 

For what part of repair you need the extra information? All the information is already available. I think everything you need is actually in this topic. Of course somebody could do step by step instruction. If I get to repair one then I might do that. But maybe cold temperatures here makes them last longer.

 

My CM of my 2005 Prius died already in early 2012, so I had to get a new one, but decided to go with a salvaged one. A new one would've cost about $ 2000, the spare one came at about $ 200. But even that money couldn't be reclaimed as Toyota Switzerland didn't receive information about the extended warranty, and it seems only very few European models suffered from this problem.

@Matt:
So, I'm still riding around with an offset on my mileage, and even if I'd repair the old one now, the mileage would be too low. Would you mind sharing also the information on how to reprogram the EEPROM with the mileage counter? I'd like to get my official mileage back. I find it more convenient when bringing the car in for the regular service, and, well, I enjoy fiddling with electronics in my spare time.

 

"Replace all 3 of the surface mount caps and the voltage reg ic and it will be fixed" isn't exactly all the information you need for the fix.
I can point to them on the board. I know which 3 caps. But the question remains as to the capacitor codes or links to the caps so we can order them and complete the repair. That's the part of the repair I need the extra information.

 

Capacitor values are visible on the pictures. You should be able to pick ones with correct dimension by just looking at the picture. And if dimensions are wrong it shouldn’t be that big of a deal. You can even use non-surface mount capacitors.

 

oschn,
This thread has information about programming the EEPROM chip. The biggest issue is that the 93C66 chip is mounted under the glass display and it's hard to get to without destroying the meter, we learned this the hard way. We designed an adapter that allows connection to the EEPROM chip without affecting the screen. Additionally we wrote a program that converts the desired ODO value to the proper HEX code and loads it into the chip. If you want to pursue it you'll need a chip programmer which can be found affordably online, take your meter apart and hook your programmer up to the chip. Download the chip data and email it to me and I'll edit the code for you so that it reads the right mileage and then you can program it back in.

Matt

 

Texas Native,
This is a 4 page thread and your having issues utilizing the data contained within it, I hope that you don't have hybrid battery problems and try to read that 80 page beast. There are countless videos online that you can watch if you need help replacing components on a circuit board so I won't be making one, sorry.

Here's your shopping list:

From Post #3 the regulator chip is an Infineon TLE4278G 5V Low Drop Fixed Voltage Regulator. Link
From Post #46 the upgraded 16V 220uF Cap that Toyota is using is a Nichicon UUD series. Link (Thank you Ben Edwards)
From Post #34 the other 2 Caps are 35V 10uF and 330uF, you can choose which ever brand you like but we use Panasonics.
10uF Link. 330uF Link.

I hope that helps you get your meter fixed.

Matt

 

Sorry my persistence for help getting the right caps ordered garnered a bit of a condescending response, Matt. But I do genuinely thank you and all others in this thread for the links and all the info. More than anything, I hope this thread helps others be able to fix their #%@* combo meters as well. Now - off to get the job done. Cheers.

 

I was not aware of this separate thread about the Combination Meter problem, so I posted my dealing with how to get the CM repaired in the last page of the thread about the TSB for this issue. It appears that the output cap of the 5V regulator is the critical component and to give an extra safety margin, you can also add a small capacitor to the watchdog timeout to give the processor more time to reboot. Thread is here:
T-SB-0172-09 Combination Meter - Intermittent Display | Page 6 | PriusChat
I also included my fix of the electro-mechanical issue that pEEF was hinting at.

 

No big deal with the caps supply just get them from Mouser. They have a very high quality Panasonic Low ESR line. I try to use radial caps to replace sm caps when I can space permitting. They will never fail again. I usually replace the caps in the swx mode section too especially the start up cap. The start up has to be exact same capacitance or sometimes it will not work properly.

 

Based on Post #34 (picture of new combo-meter from Toyota), C3 is a 22uF cap, not a 220uF cap as specified in post #71 above. C3 should be part number UUD1C220MCL1GS from Nichicon.

C3 (regulator output cap) is the most important cap in the circuit - the one that keeps the TLE4278G regulator from oscillating (it's a common problem with regulators). Although the TLE4278G only requires a 10uF cap (per the TLE4278G spec sheet [1]), if you look at the UUD1C220MCL1GS (22uF cap) data sheet [2] ("stability at low temperature" section), you can see that for a 16V cap, the capacitance drops by a factor of 2 at -25C (-4 Fahrenheit) or to 11uF. There is also a 20% tolerance on the cap value. In one application note [3], Infineon recommends a 22 uF cap.

You could probably get away with just changing C3 if you don't have the equipment or inclination to change the regulator. Also, electrolytic caps have a "+" and a "-" terminal. Make sure you install the new cap in the same orientation it was originally in, or it will probably explode (really!).

Aluminum electrolytic capacitors have a finite lifetime. I'm calculating a "load life rating" [4] for C3 of about 16 years in a 60C (140F) car. C1 and C2 have similar lifetimes. So your car would have to sit in the hot sun continuously for 16 years before the caps would (theoretically) fail. Since it's only sunny and hot for part of the day, and during half of the year in most locations, the caps should last a lot longer depending upon the climate your car is in, and whether you garage it or not.

My car started having the combo meter blanking problem about a year ago (out of warranty for this problem). During the rare times when it is blank, I have a speedometer and fuel gauge set up on my "Scan Gauge".... but I'm going to fix this problem because it bugs me when things don't work the way they are supposed to. Thanks everyone for this great thread!

References:
[1] Infineon TLE4278 Data Sheet
[2] Nichicon UUD capacitor data sheet
[3] Infineon "What Designers Should know, Introduction to Automotive Linear Voltage Regulators" (page 23)
[4] "Aluminum Electrolytic Capacitors, Reliability"

 

Neo,
Thanks for your input and yes you are correct that C3 is the main reason that the meter won't power up. When we rebuild these meters we replace all 3 of the SM Caps and believe me when you take them off you will see why. They all leak.

As far as the ratings on C3 much research has gone into this and they are most definitely 220 uF like we have discussed before. Here is the packaging from the caps in case there is any question. I've rebuilt close to 100 of these meters with the Nichicon UUD series 220uF caps as replacements for C3 and they work great.



Matt

 

Note that the Combination Meter sits directly under the windshield in the top of the dash. The temperature in that location can get a *lot* hotter than the 60 degC than NeoPrius suggested. This would also explain why C3 is leaking. And leaking is immediate capacitance loss and increase of impedance.
I tested my failing CM and by just adding in parallel to C3 (on the underside of the PCB) a flat SMD Polymer Aluminum capacitor that I had laying around, I could no longer make the CM fail. Add the increase of capacitance for the watchdog timebase and re-soldering TR10 leads and your CM is as good as new...

 

How 'bout that. The capacitor part marking is not consistent with the data sheet part number. Thanks for correcting me. I was unable to edit and correct my posting above (#75), so I hope it does not mislead anyone.

Digikey has all of the parts in stock if you want to save on shipping.

Now that I think about it - I measured the temperature of the deck on my back door when I noticed my poor dog dancing around back there before leaping down the stairs. It was over 170 degrees F, and it is not black like the Prius dash (I promptly put a carpet back there on the deck for my dog). Automotive caps are rated up to 105C (221F).

 

Digikey is great. They still ship for free if you mail them a check/order form.

 

Hi All,

Great thread. I have a 2007 with 152K miles. My combo meter is regularly flaking out. I was able to find one in a local bone yard from a 2009 with 151K miles. I am willing to "forget" the 1K mile difference. However, I have seen conflicting comments on whether the VIN is stored in the combo meter. If it is, how can it be changed? If it's not, can anyone see a reason why I shouldn't just swap in the 2009 and move on?

Thanks,
Bill