Hello,

I just acquired a 38,000 A340E and sadly it has the codes:

62: 1 solenoid valve and ECM. Check wiring between No. 2 solenoid valve and ECM. Check wiring between lock–up solenoid valve and ECM
63: Defective no. 2 shift solenoid, open in wiring harness or short circuit.

42: VSS, vehicle speed sensor
43: No STA (Starter) signal to ECM


The car was dropped off, and when I went to move it, it had like NO power... felt like throttle wasn't doing much and with revs like I would expect to take off from a red light "casually" the car barely moved. Enough throttle to break the tires loose in a normal situation moved the car a little more. had to drive 200 yards - then, it felt fine, so i tried driving it and it dint want to to shift... so I turned around, and it was then fine. Total of 500 yards of driving MAYBE. 80% of the time is has the "now power" condition like a giving a speed boat a little throttle - a long drawn out, minor response to the throttle is all I get.

check the wiring at the tail and middle of the tranny, looks fine connectors were clean inside and secure when i unplugged them to check

tranny fluid smells fine, looks fine... and the car only has 38,000 miles! should be a bad trans?


please help if you know where I can start =(

 

Hello,

Long time no see. As unfortunate as it is, diagnosing transmissions over the wire is not the best way to go about things, but we will try anyway . Judging by the mileage, it is safe to assume that the car was parked for a while; combined with a shier amount of codes stored in the system and the car's behavior, I would venture a wild guess and assume that it may be an ECU fault, since older Toyota ECUs are well known for leaky capacitors, and all the royal wonders those capacitors may cause down the road.

That said, before we would get ahead of ourselves, we should exclude all other variables. Codes 62 and 63 are remarkably similar, the only difference is that 62 is for the No. 1, and 63 is for No. 2 solenoid. Good thing is that those codes specifically reference Solenoid Circuit, which means that it should be easier to diagnose, and may not be a result of a destroyed transmission. Try as I might, I wasn't able to find any manuals specifically for the GS300, but I did find a pinout for the ECU of the 1993 SC300, which should have the same setup. Pin 10 is for No. 1 and Pin 9 is for No. 2, check the resistance between both of those pins and the Ground, it should be between 10 and 16 ohms, if it is not as specified, disconnect the Solenoid connector on the transmission and check the wiring between transmission and ECU with an ohmmeter, also making sure none of the wires are shorted to Ground. If the wiring is good and the resistance is still wonky, you will likely need to drop the pan to continue the diagnostics from there. If, on the other hand, the resistance is as specified, it may be time to pay a visit to the ECU; what you are looking for are burnt out components and a very distinct smell of fried electronics, which you should be very familiar with if you have taken a bunch of old appliances apart as a kid, the best bet would be if someone nearby has a similar working car, and he is willing to lend you an ECU for the test.



As for the other codes, it all depends on what would turn out to be an issue in the first case, if you can verify that the ECU is fine and codes 62 and 63 were actually triggered by bad solenoids, then it is time to move on for a Code 42. This one is a bit trickier, since the signal from the VSS goes into the Instrument Cluster, where it gets filtered and only then gets sent to the ECU. VSS sensor is located on the transmission, right near the prop shaft, to check it, you can carefully t-pin into its middle pin, then lift one of the rear wheels up and turn it by hand while the ignition is in the ON position, there are 4 12V pulses for each turn of the prop shaft. If that's good, you will have to check the wiring, and then a signal from the Cluster to the ECU.

Code 43 is the simplest one out there, and it doesn't exactly hurt the performance of the car. Basically all there is to it is just a wire coming from a Starter Relay to the Pin 77 of the ECU. Check the continuity between one of the pins on the Switch side of the relay and Pin 77 of the ECU, if there is none, you can guess what the issue is. That said, if there is a connection missing, I wouldn't worry about it too much, since it doesn't seem to affect drivability.

P.S. 38,000 miles, that is close to nothing for a car that is at least 24 years old by now, I am still a bit stunned by your ability to dig out such gems around.. Some pictures will definitely be appreciated!

Seems like I got all of it, but do let me know if I missed something.

Hope this helps and best of luck!

 

Thank you SO very much. As always your wealth of knowledge and kindness to share it is a blessing. We’re actually headed in a last minute, much needed mini vacation. I will report back

I am confident I couldn’t do this without help like what you provided. Thank you

 

I should also ask, is it possible that the occasional (at least half the time) episodes where the car is and drive but goes virtually nowhere, similar to giving a boat a little bit of throttle and then waiting for the prop to move enough water to move the boat if that makes sense… Is it possible that that could be ECU related? Yesterday when I drove it a 1/4 mile testing out to see if it would act normal by shifting it manually from L to 2 to d (with the od button out) it seemed powerful and smooth, it did not do the “eighth throttle speed boat” feeling, but also, manually shifting it didn’t help. I ended up putting it in D and realizing I was stuck in first gear, got on the shoulder, and what seemed like five times longer than it should’ve taken, it did finally shift in the second period eventually made it into third as well.

 

Well, that's one of the caveats of diagnosing transmissions over the wire..

My best guess would be that those solenoids are responsible for gear shifting, if No. 1 solenoid is out, you will only have a 3rd gear and O/D, if No. 2 is out, you will only have 1st gear and O/D. If, like in your case, you have both of the solenoids out, then the only way for the car to switch gears is the old mechanical way, with the shifter. Position L will give you 1st gear, Position 2 will engage 3rd gear, and D will get you straight to the O/D, which is probably why the car has so many issues launching itself from the stop. This mode is mostly designed to get you home from the dead of woods filled with hungry bears, not to keep driving as if nothing happened.. The biggest issue of starting in a highest gear is that the torque converter would really have to slip a lot, doing so generates a colossal amount of heat, which can quickly ruin the transmission, so I would suggest you to park the car until the issue is resolved. As I wrote before, the issue is most likely circuit related, so the transmission may still be fine, it's just that there is no way for it to switch gears now, that's why it acts all wonky like that..

Hope this helps and best of luck!

 

Thank you so much! That “every other” gear mentality makes a lot of sense, now that you say it. The car is at a 30-year-old Toyota specialty shop, as we speak, and I am on vacation. I hope from the bottom of my soul that this is correctable, is this car is certainly a piece of history… I will report back

 

Well, it certainly sounds interesting, especially considering what kind of car it is..
Will be waiting on your report then..

 

So seems the trans is good. Wiring looks good at trans someone has tried to chase it; speed sensor has been replaced. Possibly the ECU.

 

Is the resistance of solenoids okay? Wires from solenoids go straight to the ECU, to "chase" them, all you need is to measure resistance of the wire from the ECU to the respective pins on the transmission connector.

As for the Speed Sensor, did it fix the issue? It is pretty easy to diagnose, there are 12V and Ground coming to the 1 and 3 pins, Pin 2 is for the signal. The sensor creates 4 12V pulses per one revolution of the prop shaft (not to confuse with one turn of a sensor itself).

Hope this helps and best of luck!

 

Many thanks. I will bring this (open on my smart phone that is)
with me when I go tomorrow to talk to the guys. Because of the delicate nature of the situation, it is with a professional garage… It seems that all, regardless, it will be coming back to me with it issues, which I’m sure in the end will be worth sorting out. I truly understand now why cars before the 70s, and there’s simplicity (remember I own one - 1950) are as simple as people say, yet I appreciate cars of the last decade because even in their complexity, they somewhat self diagnose. This “in between“ is quite difficult

 

Probably a bad ECU, cheap enough to buy a spare ECU for $50-70 and plug it in.

 

Got any updates? Just curious..

 

Sadly not much. Seems the trans is mechanically ok - but the wiring and or ecu may be wonky. Supposed to talk to them again tomorrow. My gut is ecu. But what’s my gut? LOL. It’s a jzx90 ecu for a 1jz and an a340e. Sadly those don’t grow on trees :-/

 

Ow, I thought it has a 2JZ for some reason.. Below is a pinout for the 1JZ-GTE ECU, Pins S1 and S2 are for the solenoids, Pin STA is for Starter Signal. Not every ECU failure totals it, some of the issues can still be repaired, like leaky capacitors or some other fried component that can be sourced from a donor ECU. If that won't help though, there are some on sale, it's the shipping that would pose some issues.



Hope this helps and best of luck!

 

Thank you so much!