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Stock Twins King
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Discussion Starter #1 (Edited)
So I have repaired a lot of speedo's over the years. It is quite a chronic issue as our loved Supra's are getting old and tired. So the capacitors start to go bad and cause it to barely move and stay under like 40mph. So just need to go buy 2ea 22uf 50V and 1ea 6.8uf 50v. Be cautious of polarity. Long leg of the capacitor is the positive. The Cap has a silver stripe donating that is the negative leg (shorter). Do yourself a favor and buy a small $8 spool of de-solder wick, like Gootwik to suck up the solder for easy removing of the old Caps.

https://www.amazon.com/Goot-CP-3515-Desoldering-Wick-Braid/dp/B00TCZSMSQ


EDIT: Some may have noticed that the Caps removed are 25v not 50v. It really doesn't matter which one you get. You may find that the lowest rating is 35v for the 6.8uf. Filtering the search to just "Automotive Purposes" really restricts the availability. "General Purpose" are way more abundant. Just get the cheapest ones close to these as these are like pennies.


 

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Stock Twins King
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Discussion Starter #4
One of our OG 1A1 contacted me on FB as his is showing speedo death. He asked If I could repair but I said save the money and hassle and just fix it yourself. Anyways, someone within this FB post said I should post here and make it a Sticky! So If a moderator sees this, maybe this can be stick'd?
 

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Hello Stu Hagen,
I just replay new sensor speed odometer on the transmission of my 95 Supra TT 6 speed but the odometer & two trip meters is busted and the mileage odometer is not moving. This is discontinued the odometer & two trip meter so do you have any new or old one sell to me. Please let me know ASAP...Thank you Stu
Best regards,
Michael T Nguyen
 

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Boost Junkie
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Hello Stu Hagen,
I just replay new sensor speed odometer on the transmission of my 95 Supra TT 6 speed but the odometer & two trip meters is busted and the mileage odometer is not moving. This is discontinued the odometer & two trip meter so do you have any new or old one sell to me. Please let me know ASAP...Thank you Stu
Best regards,
Michael T Nguyen
You probably need to check the solder joints in the odometer. Sometimes they come loose.

Steve
 

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Stock Twins King
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Discussion Starter #9
I would do as said above first to eliminate the cold solder issue. There are many links to this if you search. If not then the other option is going to "bitshtr" The odds of the ODO just going bad is slim. It also could be an issue with the pink wire feed not making to to the ODO unit. Some bypass this.
 

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415CBEFE-98F3-4A14-8055-97E4A3C38415.jpeg

Also I don’t know about repair this speedometer situation by cold solder. I replaced new sensor speedometer but not sensor speedometer issue. The pictures of my mileage is light up and it not moving. My mechanic said the odometer & two trip meters is the problem (burn out). It’s low mileage and it would be repaired. Stu said option go to “bitshtr” and I don’t understand. Please explain please...Thank you Stu & Superaforum. Best regards, Michael
 

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Stock Twins King
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Discussion Starter #12
View attachment 235137

Also I don’t know about repair this speedometer situation by cold solder. I replaced new sensor speedometer but not sensor speedometer issue. The pictures of my mileage is light up and it not moving. My mechanic said the odometer & two trip meters is the problem (burn out). It’s low mileage and it would be repaired. Stu said option go to “bitshtr” and I don’t understand. Please explain please...Thank you Stu & Superaforum. Best regards, Michael
This

https://www.supraforums.com/forum/showthread.php?1024553-WTB-Your-busted-Odometer-(actually-I-want-to-repair-it)
 

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Stu, I have a question for you on the ODO bypass that causes the code 42. I took my ODO apart and re-soldered the cold joints, but that did not fix my issue, I ended up cutting the pink wire and tying it directly to the L-R (Blue-Red) wire as most do as you posted above. This fixed my code 42 problem and made my cruise control work for the first time ever as well.

The transmission manual states that VSS NO. 1 sends a 4-pulse signal to the speedometer via Blue-Red, then to the odometer via Blue-Red, and then exists the ODO as Pink and goes to the ECU. In the process of the transfer through the "combination meter", it states that it converts the signal into a "more precise rectangular waveform" via the "Shaping circuit" inside the combination meter before being sent to the ECU.

By doing this modification are we bypassing this waveform being cleaned up prior to being sent to the ECU? I know it says the combination meter cleans it up which is typically the gauge cluster, but the logic looks like its actually in the ODO/Trip meter. Just curious if there is a downside to doing this.
 

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Any idea if there is a how to for the coolant sensor gauge in the dash? Mine stopped working. The sensor has been replaced and still a no go. Not a huge deal since I have a PRO EFI, but mildly annoying.

STeve
 

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Stock Twins King
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Discussion Starter #16
Any idea if there is a how to for the coolant sensor gauge in the dash? Mine stopped working. The sensor has been replaced and still a no go. Not a huge deal since I have a PRO EFI, but mildly annoying.

STeve
I have a diagnostic but it might not be exactly what may help. However, there is at least a quick check but requires you to remove the cluster, attach a long wire to the (yellow) screw on the coolant gauge called "T". Plug the connectors back in, turn car to on (don't start) then take the other end of the wire and touch to ground momentarily. If the coolant needle jumps rapidly to full HOT then you know it isn't the gauge. If it still doesn't budge then the gauge is busted. This diagram I use to send to people to show how to replace needles if they were removed.
Calibrating Fuel-Coolant.jpg
 

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Stock Twins King
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Discussion Starter #17
Stu, I have a question for you on the ODO bypass that causes the code 42. I took my ODO apart and re-soldered the cold joints, but that did not fix my issue, I ended up cutting the pink wire and tying it directly to the L-R (Blue-Red) wire as most do as you posted above. This fixed my code 42 problem and made my cruise control work for the first time ever as well.

The transmission manual states that VSS NO. 1 sends a 4-pulse signal to the speedometer via Blue-Red, then to the odometer via Blue-Red, and then exists the ODO as Pink and goes to the ECU. In the process of the transfer through the "combination meter", it states that it converts the signal into a "more precise rectangular waveform" via the "Shaping circuit" inside the combination meter before being sent to the ECU.

By doing this modification are we bypassing this waveform being cleaned up prior to being sent to the ECU? I know it says the combination meter cleans it up which is typically the gauge cluster, but the logic looks like its actually in the ODO/Trip meter. Just curious if there is a downside to doing this.
IMO when you do any wiring "modifications" you are not really solving the main issue. However, I agree this has been a standard "fix" for years. The VSS if you look, goes to BOTH the speedo and to the ODO. Not "then to" The pink wire mod in essence bypasses the on-board circuitry of the ODO motherboard. hence really is where the issue really lies.So for all the people who do this "mod" does fix the issues but the main cause is a faulty ODO. As far as the "square wave" that is the same thing as a PWM. Your explanation
Combo VSS.JPG
seems faulty because how can the speedo '"shape" this signal when the signal also goes to the OD circuity.
 

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IMO when you do any wiring "modifications" you are not really solving the main issue. However, I agree this has been a standard "fix" for years. The VSS if you look, goes to BOTH the speedo and to the ODO. Not "then to" The pink wire mod in essence bypasses the on-board circuitry of the ODO motherboard. hence really is where the issue really lies.So for all the people who do this "mod" does fix the issues but the main cause is a faulty ODO. As far as the "square wave" that is the same thing as a PWM. Your explanation seems faulty because how can the speedo '"shape" this signal when the signal also goes to the OD circuity.

I used that wiring diagram page as well and I am sure it is right, however when I traced the wire behind the dash, I didnt see where the L-R from the VSS split into 2 separate L-R wires, one to Speedo and one to ODO.

Additionally, this is the page that I was referring to where it discusses cleaning up the signal through the combination meter. I guess I just dont understand why Toyota has it going through a shaping circuit and then to the ECU via the pink wire, when we are cutting the pink wire and tying it directly to the L-R, seemingly skipping this step. The ECU is still getting a 4-pulse waveform this way, just not "cleaned up" is how I read it. I agree that this isnt the correct way of fixing this issue, just wish the ODO's werent so ridiculously expensive from Toyota.

242780


Lastly, this diagram also supports what you are saying that the L-R is sent to the two seperately:

242781
 
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