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Discussion Starter · #1 ·
Hey guys, I lived with an odometer in my car that had cold solder joints in the odometer for quite some time. During that period, I noticed I'd lose cruise, the trans was shifting erratically (up, down, up, down, up, up, down, etc.), and I even busted a forward clutch piston (which up until the resoldering, I thought may have been related, but wasn't certain.).

So, I finally did the resoldering and what a difference it made. Cruise control has always been there, the car doesn't start making crazy shifts, the unlocking/locking of the torque converter is without shutter, and the all around operation of the transmission has improved. There is no longer a violent engagement between park and drive, park and reverse, reverse and drive, or drive and reverse. I highly recommend that everyone who is having this issue not only complete the repair for the obvious benefits, but had I known the extent of increased abuse my transmission was experiencing, I would have done it long ago.

As for where exactly I resoldered, on the odometer circuit board there are three capaciters with a total of 6 solder points. I retouched these six and all problems related have abated.
 

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The Great Kruso
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Definitely highly recommended, especially on autos.
 

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The Great Kruso
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my stock auto would have the "hard" shifts from Park to Drive situation once in a long while... maybe 3 times a year. My odometer seems to be good tho. Is there any other contributing factors or should i just open that sucker up and resolder them.

Tsung
 

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The Great Kruso
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my stock auto would have the "hard" shifts from Park to Drive situation once in a long while... maybe 3 times a year. My odometer seems to be good tho. Is there any other contributing factors or should i just open that sucker up and resolder them.

Tsung
It's not even worth talking about it when it only takes ten minutes to go over the solders. Every MKIV I've ever owned needed the re-solder.

Kruso
 

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Hey guys, I lived with an odometer in my car that had cold solder joints in the odometer for quite some time. During that period, I noticed I'd lose cruise, the trans was shifting erratically (up, down, up, down, up, up, down, etc.), and I even busted a forward clutch piston (which up until the resoldering, I thought may have been related, but wasn't certain.).

So, I finally did the resoldering and what a difference it made. Cruise control has always been there, the car doesn't start making crazy shifts, the unlocking/locking of the torque converter is without shutter, and the all around operation of the transmission has improved. There is no longer a violent engagement between park and drive, park and reverse, reverse and drive, or drive and reverse. I highly recommend that everyone who is having this issue not only complete the repair for the obvious benefits, but had I known the extent of increased abuse my transmission was experiencing, I would have done it long ago.

As for where exactly I resoldered, on the odometer circuit board there are three capaciters with a total of 6 solder points. I retouched these six and all problems related have abated.
Hi,
I’ve had that hard jerk between park, reverse, and drive. With the O/D light blinking off and on at random times. Just recently however, the manual mode comes on randomly and the transmission refuses to shift when in drive. I must mention it does shift smoothly from L-D when i shift manually during the random manual mode. Do you think this could be a bad case of cold/cracked solder joint in the odometer board? The car is all stock TT auto. Any guidance would be much appreciated? Thanks in advance.
 

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Hi,
I’ve had that hard jerk between park, reverse, and drive. With the O/D light blinking off and on at random times. Just recently however, the manual mode comes on randomly and the transmission refuses to shift when in drive. I must mention it does shift smoothly from L-D when i shift manually during the random manual mode. Do you think this could be a bad case of cold/cracked solder joint in the odometer board? The car is all stock TT auto. Any guidance would be much appreciated? Thanks in advance.
It’s gonna be a code 42 I believe. You can also do the basic Toyota cruise control test. Either rehear the solders which I’ve done several times till it just wont work consistently anymore or do the vss splice mod and call it a day. Haven’t come back to me for years since
 

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It’s gonna be a code 42 I believe. You can also do the basic Toyota cruise control test. Either rehear the solders which I’ve done several times till it just wont work consistently anymore or do the vss splice mod and call it a day. Haven’t come back to me for years since
Thanks! Gonna try and get a friends odometer to swap and see If the problem disappears assuming he doesn’t have cold solder problem as well. Do you think this would be a valid test to rule out the solder joints? I’m such a newbie I’ve never touched a soldering iron in my life.
 

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Cruise Control Diagnostics
Here is the cruise control test. you are most concerned about the speed sensor. my 93 supra worked with type A code. you want to drive the care above 25mph and see that the cruise control light flashing constantly. if it is constantly on, then you know that ecu is getting the wrong signal and either your VSS or more likely your odometer solders are shot. id say just make the VSS splice instead of trying to resolder.

Here is the reason and procedure on how to do it
code 42 VSS cause trans to act weird?
 

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Supraforums Member
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Discussion Starter · #11 ·
Thanks! Gonna try and get a friends odometer to swap and see If the problem disappears assuming he doesn’t have cold solder problem as well. Do you think this would be a valid test to rule out the solder joints? I’m such a newbie I’ve never touched a soldering iron in my life.
Yes, swap the odometer and see how it goes. So long as he doesn't have cold joints, it'll have the same effect as if yours had been repaired. I wouldn't do the splice, especially if your future plans include a stand alone. The splice is a band aid, it doesn't fix the problem.

As far as being a newbie, it was the first time I'd used a soldering iron too. It's almost foolproof if you're just touching and reflowing them - if I could do it, so can you. My suggestion would be once you reflow them, do some practice on circuit boards to get experience removing the old solder and replacing the new. My suspicion is that the solder used by Toyota wasn't the best and is more prone to cold joints. I've got no proof of that, but it's my suspicion because after doing my reflow (a year or so), I ended up removing the old solder and flowing in new.
 

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So I have no error codes or blinking lights but I noticed lately sometimes the revs seem to go up and it shifts a little harder from 1-2. Sometimes it is smooth and sometimes it's a little abrupt. It honestly feels like I have no boost at those moments. Is this of any benefit if you do not have any obvious codes or blinking lights?
 

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Boost Junkie
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Hi,
I’ve had that hard jerk between park, reverse, and drive. With the O/D light blinking off and on at random times. Just recently however, the manual mode comes on randomly and the transmission refuses to shift when in drive. I must mention it does shift smoothly from L-D when i shift manually during the random manual mode. Do you think this could be a bad case of cold/cracked solder joint in the odometer board? The car is all stock TT auto. Any guidance would be much appreciated? Thanks in advance.
100% that’s your problem. I answered your other thread.

Steve
 

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Wow, I'm glad I randomly stumbled across this thread. My NA auto does lightly "clunk" going from P to D and D to R, etc. But the biggest is that it has a heck of a time getting into OD on its own anymore. I have to take my foot off the accelerator down to like 35 or 40 and then it will often shift up into OD then. I never would have suspected loose solder points in the odometer as anything related to this!
 

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I can say that this was not my problem. Nothing changed after doing the re-soldering. I am slowly getting closer to a solution I hope.
 

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I can say that this was not my problem. Nothing changed after doing the re-soldering. I am slowly getting closer to a solution I hope.
If you want to rule out the odo and go straight to the ECU, you can perform the pink wire mod temporarily.

If the problem is still there and the ECU is good, it’s either a bad VSS or two OR an actual transmission issue.
 

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My issue is boost related. I drove the car home Friday night and noticed as the revs went up the boost went down. I might of hit maybe 10-11 pis and watched it go down which is why the car felt like it had no power and the auto gear shift felt weird because you noticed it more with no power. With boost the shift feels normal because there is power. So I converted my car to True twin doing this way...


Other than the increased lag, I hit 1.09 bar / 15.8PSI no problem time after time in 98 degree weather and the shifts feel normal. So now the question is when I put it back in sequential mode is it a VSV issue or maybe is the ECU not telling them to do their thing in the proper order. I'll probably start another thread for this to keep this on the odometer subject.
 

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Did the cold solder fix here and my car reliably shifts into overdrive now. Odd to think this would all be affected but I drove the car a bit last night to confirm. Shift transitions from P, R and D seem a little smoother, too. But mostly I'm just happy to have OD back.
 
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