No speedo, odo, wheels not turning on MFD.

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k8rhino,

Welcome to PriusChat.

The randomness of the symptoms plus the age of your car suggests that
your 12V battery may be on its last legs. While it is somewhat early, the
12V battery is generally good for ~4 years, who knows what kind of abuse
may have occurred before you got the car.

Further support for this idea comes from everything appearing to be fine
after the car has run for a while. This would come from the 12V battery
being recharged while the HSD system is operational -- and slowly loosing
the charge when it's off. You could go to most any competent garage or
batttery shop and get a voltage check.

I'm no expert, so let's wait and see what other more experienced folks
have to say.

 

As soon as the car boots up, 12V should be supplied by the inverter. At this point you can remove the 12V battery and everything will still work, so I'd be surprised if your problem was being caused by a bad 12V battery. It's not impossible; the 12V battery could be dragging down the 12V buss, but that is not a common failure mode.

I think it's more likely that you have an intermittent failure in the speed sender system, which takes out the speedometer. This is consistent with the wheels not turning on the MFD. A loose connector or bad wire may be causing it, or the electronics in that area could be failing. Have any error codes been logged?

Tom

 

Do you have a digital multimeter? If so, I suggest you measure voltage across the 12V auxiliary battery after the car has been sitting for a couple of hours or more. A fully-charged battery should show 12.6V or better. When the car is READY then the voltage should be ~13.8V, as the DC to DC converter maintains this voltage on the 12V bus.

If the battery is much below 12.6V when the car is IG-OFF, that I suggest you install a new one. Random Prius electrical problems can sometimes be attributed to bad voltage on the 12V bus causing the ECUs to become weird.

 

Anybody think to check the GAUGE fuse? 10 amps, sort of in
the middle of the driver's side fuse block.
.
_H*

 

I have several Prius taxis. About half the taxis in my town are Priuses. Many have had this problem, usually at around 200,000km but sometimes earlier. Intermittant at the start and eventually more frequently. It's a serious issue in a taxi because when the speedo goes the meter will not register mileage and there's no point going to work. Sometimes changing the battery helps for a while. For a quick fix often disconnecting the positive battery post (10mm) and reconnecting brings the speedo back to life. Other times you just have to wait it out. Occasionally shutting the car off and on repeatedly seems to do the trick. Mostly it seems that it will only go on again by restarting the car, though I left a car running with a dark speedo for 15 minutes once and the speedo was on when I came back. All three of my 200,000km+ Priuses have had the speedo board replaced at least once. You mention hard to shut off - ya I read elsewhere that car doesn't want to shut off when it can't judge that it's stationary. That problem related to the dark speedo but just because it goes away doesn't always mean the speedo comes back on. Add to this symptom that the rear hatch sometimes won't open when dash out and/or hard to shut off - perhaps for the same reason - that the car does not want you to open the hatch when it thinks you might be moving.

Today I had no speedo again in a car that has about 450,000km on it. I suspect it happened because I shut the car down while putting a window up. I disconnected the battery and reconnected. Presto! I didn't test it to see if problem would occur again if I did the same thing but maybe this is something to avoid....

Replacing the speedo board has been the only reliable fix that we've found here. It's kind of pricey, but it's one of the few things that go wrong with these cars. It sure would be nice to figure exactly where the problem originates though so it could be repaired more cheaply.

 

I've heard of the gauge cluster issue, but am unsure what impact the cluster has on the MFD. If it's actual corrosion on the contacts at the cluster board connector, this could cause problems with the CAN/LIN/BEAN.

On the industrial side, I've been driven insane by random glitches caused by poor contact due to corrosion. With time and patience, this can be reliably scoped with a MSO/VSA or similar scope

Eg: this is a CAN glitch caused by noise due to a corroded contact. It took 4 hours of monitoring to build a history, good thing Agilent has scopes with deep memory and smart software



The glitch I highlighted with yellow circles. Will research this when I have time

Also, make sure all the ground points are good. When my Prius was one year old, I went on a hunch and removed the negative cable and bolt that goes into the unit body. Photo by another PriusChat member



The bolt for the battery ground already had corrosion starting on it. I smeared on some electrical contact grease, and snugged the bolt up again.

I'm now in the habit of backing off the ground bolt at the unitbody, and snugging it up again, twice a year

We need to build a statistical failure mode analysis on this problem. Eg: was car operated in high humidity areas? Near salt water? Kept outside all the time or garaged?

It would be a royal PITA for the owners affected if replacing the cluster was completely unnecessary. That is, if just pulling the connector off and pushing it back on would have been enough to clean the contacts and restore reliable operation

 

Yeah, this anecdotal evidence sounds a lot like a resistance build-up somewhere, resulting in possible under-voltage to some components, or inconsistent voltage. The real danger here is that consistent under-voltage (brownout) can lead to stress of the electronics, and failure. This kind of problem sounds very reminiscent of PC mobo issues with power supplies starting to let go.

I've had several PC mobos die on me, due to bad power supplies. The power supply starts going out, eventually dying, and it usually takes the board with it (probably some spike as it died), but certainly stress to the electronics as it was delivering fluctuating voltage. Since then, I replace my power supplies every 2.5-3 years. And they are ALWAYS replaced when installing a new mobo (at least, back in my Windoze days ).

With the anecdotal information by both jayman and victaxi18, I'd begin to wonder about resistance due to corrosion - somewhere. Battery and battery cables are most logical suspect, but even other areas may be suspect. I've found "in the old days" with the round fuses, that just rolling them within the contacts helped clear corrosion (not the battery kind, just oxidization - you know, the contacts get brown). Or taking them out and using some fine steel wool on them. With the newer type, maybe some take them out, a bit of steel wool or sandpaper, and a contact cleaner (non-corrosive, and non-conductive, of course), and reinsert the fuse 2-3 times. Do it to all of them.

With so many electronics on the Prius, probably need to think much more along the lines of "it's a computer that just happens to have wheels".

 

My background is military electronics - I was a 98K - and industrial/telecomms electronics. The components selected for telecomms use, industrial use, and certainly for military use, have far stricter design specs: eg, must be resistant to voltage excursions with minimal impact on MTBF

The cluster - Combination Meter - apparently has 4 connectors. So there is a lot of potential for a marginal connection to bugger things up, and perhaps just unplugging each connector, and reseating it, might "cure" the glitch.

We did a lot of that in the Army and also in industrial work. For example, one client in the mid 1980's with a Honeywell TDC 3000 had a lot of trouble with the Universal Stations and History Modules in the control room. The control room was filthy dusty, which was and still is a no-no

I would spend half a day powering down the control room Honeywell stuff, and patiently unlatch and reseat every paddle board in the rack. The US's had 10 boards in their racks, the HM's had 5 boards in their racks. Ah, the good 'ole days

Anyhoo, the four connectors of the Combination Meter

Connector 1



Connector 2



Connector 3



Connector 4



The combination meter as it relates to the dash assembly



The combination meter networking



So yeah, a bad connection would cause no end to the grief. When the dealership unseats all the connectors - magically wiping the oxidation off in the process - then yanks out the "bad" combination meter, sticks in the $1,000 new one, and reseats all four connectors, everything works again

Off warranty, I'm wondering if Toyota just s*** cans the "bad" clusters, or sends them off somewhere?

 

If only there were an all-gold-plated-connectors option...

 

Depending on the environment, even gold-plated isn't trouble-free

I prefer that special contact grease that eliminates oxidation of the metals. Problem is, folks tend to just glop it on like butter on toast. That causes problems too

 

I have seen plenty of gold connectors fail. They are better, but not perfect.

Tom

 

Heavy drinking is *always* an option.

So is screaming the F Bomb at the Combination Meter, while swinging a wrench or sledgehammer ...

 

In general, I heartily agree. However, I've often found that what "should be" - ain't. And you still have the possibility of a bad batch of components (caps, resistors, etc.)

And I always recall my dad saying (he was a fighter jock), "you always have the comfort of knowing that your plane was built by the lowest bidder".

This is what I suspect the real culprit is. However, repeated jolts, stoppages, etc. to the equipment may result in a shortened life. I'd highly suggest to the OP to disconnect, examine, clean (if necessary) and reconnect the connectors to this equipment.

 

I blame the heavy boozing ....

 

I agree 100%. Eg the 2004-2006 Prius MFD problems. Actually more of an assembly build issue - weak/bad solder joints - than an outright individual component failure mode

Yes, such a warm and fuzzy feeling ...

The vibration can introduce odd failure modes if a contact is weak/poor, either caused by a bad solder joint - eg MFD problems - or just corrosion on the contacts

According the the ALl Data souce, there are 4 distinct connectors used on the Combination Meter. Any one of them, or a combination of them, can cause issues

Here is an adventure I had to deal with last fall with the Bryant Evolution furnace in the home I bought around a year ago.

Around October, woke up and thought hmmm a bit chilly in the house. Went to the Evolution thermostat in the hallway, it had the indoor temp in dim gray, and SYSTEM MALFUNCTION in black bold type overlaid.

So I called the local Bryant guy, actually he used to own the house and I bought it off him. He rushed over and started going over everything. The diagnostics pointed to loss of network communications

Note: the furnace, Heat Recovery Ventilator, outdoor A/C unit, and indoor Evolution thermostat all run off the 4 wire Evolution control network. It works like A-B's DeviceNet

He readily admitted he didn't know anything about that sort of error, so I offered to help him diagnose. The HRV actually has a Bryant Network Interface Module, to control the HRV low/high speed. It was located inside the furnace next to the other control board.

As soon as we took the access panel off, and had a strong LED flashlight, I noted a couple of the network wires had popped off the terminal strip. I *hate* terminal strips, they require stripping wires, and these were 22 ga wires.

The wires hadn't just popped out, they had BROKEN OFF. Playing a hunch I wiggled around the other wires on the terminal strip, and a couple more broke off. The guy claimed he had hired an electrician to wire everything up, and at first they had trouble making everything work

I prefer hot-melt over mechanical stripping of small gauge wires, it's too damn easy to knick the wire. It *will* fail at some point. I have an old hot melt and dug it out of the box

So with all the wires properly stripped and put back in the terminal block, everything worked fine. In another month or two, that nice long transition up here from heat to cool mode, I'm going to go over every single wire on every single terminal strip, as I no longer trust what this doofus electrician did

Why didn't they just use a 66 punch down block? It's low voltage stuff, a terminal strip is a bad idea. This is just one example of a failure mode that is practically built in

It could be with these reported combination meter "failures" a simple - but careful - unseating and reseating of all the connectors may very well solve the problem

Unless you have access to a VSA or similar scope with deep memory, that will automatically freeze frame network glitches, you'd never know if random noise or weak signal is the culprit.

 

Howz that tail light working, Mr BACNet?

Blinky blinky flicker flicker ....

Baaaaaaaaaaaaaaaaaa