SolaraGuy.com

I've got an 04 Solara XLE V6 with about 145000 miles on it.

For the past 6~8 months, my tachometer is reading below zero at idle, and reading low while driving. I went to the dealer, they said the cluster was bad, but that it wouldn't effect the motor in anyway.

I was driving down I-70 yesterday at 70mph (w/cruise) with the windows down and the A/C off for about an hour. I look down and the check engine, TCS and VSC lights are on. Sigh. I go to the dealer. They say its a PO420 core, and that the catalytic convertor is clogged/clogging. They cleared the code and I went home.

Is it worth trying to "clean" the catalytic convertor out? Unbolting it, and trying to get whatever loose broken-down material is in there, out. I really don't want to replace it right now, we are in the process of buying a fully loaded Camry Hybrid, and I would rather spend my time than my money (fixing, not replacing)

Thoughts? Is there a chance the tach and catalytic convertor issues are related?

You can try taking it off and flush it like this




And for the other stuff, i think it was tied along with the catalytic converter

I appreciate the video!

But the tach is still off. At idle it still reads below zero.

Have you tried unplugging the negative terminal from the batter for 30sec and plug it back in?

SteveSolara wrote:Have you tried unplugging the negative terminal from the batter for 30sec and plug it back in?

yup. Let it set for 30 minutes without a battery connected to totally clear anything. Tach is still wrong

hmm i guess the only other way to check for sure is to actually take it out and check behind it and see whats up

It may not be getting the correct voltage. I don't have it front of me but my voltmeter has a setting for rpms. I've used it to check readings at the car's ecu. There is a different wire that feeds the tach directly though. I'll take a look at the PDFs tomorrow evening to see if I can locate the specific wire that may be at fault.

GzNutz wrote:It may not be getting the correct voltage. I don't have it front of me but my voltmeter has a setting for rpms. I've used it to check readings at the car's ecu. There is a different wire that feeds the tach directly though. I'll take a look at the PDFs tomorrow evening to see if I can locate the specific wire that may be at fault.

I've got the EWD from toyota, I could find it if I thought that would help. If I found the wire, and it wasn't giving enough voltage, then what? That would mean the Cam position sensor is bad? Or whatever feeds the tach. That seems even worse, lol.

SteveSolara wrote:You can try taking it off and flush it like this

Yuck, the PO420 code is for bank 1 I believe. And the Catalytic convertor is built into the header, so I can't even see through it.

So, I need a new header/converter. This is slowly becoming an extremely expensive fix. I am hoping the O2 sensor is going, but I've never known one to "die slowly". They have always "just failed" in my experience.

It may just be a short in the line. Hopefully it's just a loose wire otherwise running a new wire may be a cheaper option to tackle before replacing a cam sensor.

well, Its the bank 1 sensor, so it's the side nearest the firewall. Yuck. Giant pain in the ass. I could barely get the multimeter leads down to test the O2 sensor. Sadly, it was within range. So I am guessing my catalytic converter is on its way out. I am going to go flog it for a bit on the highway since it's pretty warm today (90F) and see if it comes back. If it does, I will probably end up letting a shop replace it.

Yuck.

As for the tach, I have been reading the EWD, and can't seem to find which wire actually sends the signal. I assume its a 5v signal, but I'm not sure.

I uploaded it to 4shared, not sure if you need an account to access it or not: (looks like you do)

http://www.4shared.com/office/2BumrrR9/EWD.html

If you access the ecu behind the glove box the wire for the tach is black with an orange stripe and is in plug F pin 5. According to the diagrams it should be the same going to the tach itself. I've got the position of plug F from my urd maf-sc manual, it may be referred to as plug A in the toyota manual. I will be tearing into my ecu on Wednesday and can take pics of the wire if you'd like.

I'm guessing that if your cam sensor was the issue you'd have many more problems than just a bouncy tach, ie ignition/revving. It most likely is a bad cluster and you're best bet would be a pick and pull. LKQonline.com has them listed for around $120.

I hope this helps.

GzNutz wrote:I'm guessing that if your cam sensor was the issue you'd have many more problems than just a bouncy tach, ie ignition/revving. It most likely is a bad cluster and you're best bet would be a pick and pull. LKQonline.com has them listed for around $120.

I hope this helps.

Very helpful indeed! Thanks a lot

And sadly, you are correct, it is the cluster. Stupid opitron gauges are expensive. But thanks for the link!

Hey i found this video, hopefully it helps