Speedometer not working correctly?

I think the issue we are having is the code reader that you are using is not pulling the codes that are there. The fact that you have no codes but still erase codes and the lights go off, indicates there are codes there. Also, the fact that the lights are on, there are almost always codes to go along with it in these modern vehicles. So again, I think it is a scan tool issue.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I would suggest one of two things. First, don't erase the codes when the lights come back on and have the dealer or someone else check them as well. Second, let me know what scan tool you are using and we will see if it has the ability to communicate with the ABS and hybrid system. More then likely this is a speed sensor issue or hybrid battery issue so it will need to communicate with these modules and not all scan tools can do that. Thanks

The Toyota dealer checked all the codes with their code readers and said that there were no codes showing on my Toyota. This was while the warning lights and messages were on the dash and i had not cleared them. Toyota did the same thing with their code reader, they cleared the codes, even though there were no codes on their readers and the warning lights and messages went away. The Toyota dealer said without any real codes, they have no way to find the problem or fix the problem.

Okay. Sorry but this doesn't make sense so I understand your frustration. If the lights are on but there are no codes, why does clearing codes (that are not there) make the lights go out, only to come back on?

Next time the lights are on, can you get a picture of the cluster so that we can see what messages and lights are on? Thanks

These are pictures of the warning lights and control panel messages, before they are cleared with a code reader, even though the Toyota dealers code reader says that there are no error codes, with the below messages still on the panels.

Okay. The only thing that makes sense with this is if the 12 volt battery is weak causing these lights to come on. Each of these warning lights is associated with codes so if there are truly no codes then a weak battery would make sense.

Here is a guide that will help with load testing the battery:

https://www.2carpros.com/articles/car-battery-load-test

Most any parts store will do this for free so let's do this and go from there.

I thought the same thing, So since this was happening with my old battery, I replaced the battery with a new one. Vehicle did the same thing with the new battery. That was before I took it to the Toyota Dealer who said everything checked out fine, even though the alarm lights and warning messages were showing. They said they could not find or fix the problem.

If the dealer looked at it with the lights on but said they couldn't find the issue sounds odd as well. Did they give any documents or any indication what they suspect the issue is?

This just doesn't make sense so I am going to suggest two things. First, seek a second opinion from another dealer when the lights are on. Second, we need to check the battery terminals and cables.

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

I am convinced that this has to be related to the 12 volt battery so if it is not the battery itself then maybe the cables are loose or there is high resistance in the cables.

Toyota of Knoxville, said they looked at everything and could not find anything (with lights and messages on dash). I have contacted every hybrid repair shop within 250 miles for any suggestions. Most think that it is an electrical issue after I checked everything (battery, battery cables, plugs, fuses). Best suggestion from a few is that there is a loose ground wire, but they also added "Good Luck Finding It", because there are so many ground wires and I can not find one diagram to even show where to begin looking for them.

Hello,

I'm Tom and went through this a little. I've attached all the diagrams for your grounds. Maybe you will find a bad one, a wet area or something just not right when you look. Can you recall the very first time this happened? Was there anything out of the ordinary, spilled coffee, driving down a bumpy road, Snow storm, lent the car to someone, a jump start? Anything at all. Think back to that very first day and the few days before and let me know if you can recall anything.
Tom

Thanks for the diagrams...This will really help me locating all the ground wires. As far as what happened when this problem first showed up, I was sitting at a red light for about 60 seconds on a beautiful sunny day and it was about 36 degrees F, absolutely nothing was going on inside or outside the vehicle. I had just drove from home about 15 miles before I got to the red light. :(

it sounds like the cluster might be bad. To be sure lets do a CAN scan which is the future of automotive repair, you can get a CAN scanner from Amazon for about $50.00. here is a video to show you how:

https://youtu.be/InIlnsjOVFA

Please let us know what you find. We are interested to see what it is.

With alarm lights on and warning messages on display, Autel obd2 scanner says that there are no error codes, but if you clear codes with Autel obd2 scanner, everything goes away ???

did you do a CAN scan? please click the video link.

I ran all available scans with my Autel Maxilink ml329 code reader and obdii scanner.
The Toyota dealer (Toyota of Knoxville) ran all available scans with their scanner.
All scans delivered "no codes found" (multiple times), even though alarm lights and warning messages were showing on the dash panel at the time of the scan. When "erase codes" was performed by both the Toyota scanner and my scanner (multiple times), all alarm lights and warning messages went away.

does the speedometer work now?

Speedometer only drops to zero for 1 To 3 seconds, when alarms first appear, then it goes back to reading correct speed.

With no codes I would say the cluster needs to be replaced. here are the instructions. You will need to get a used unit or rebuilt from a place like AER in California. Check out the diagrams (below). Please let us know what happens.

Well, after everything I tried that did not work, I noticed that the positive battery connector was corroding every couple of weeks and needed to be cleaned with a metal brush. I checked Toyota's part number for the metal connector and found that the correct replacement was a silver metal connector. The one on my Toyota Highlander was a copper metal connector. Since I had tried everything else, I ordered the new silver metal connector and installed on the positive cable. It has now been about 3 weeks and I have not had any problems since replacement. I find it hard to believe that this was the problem, but apparently it was !!!

Wow. That makes two of us but I have seen crazy things to know it is possible.

Thanks for the update. That info will surely help others.