order these off of my list in post #1 of this thread (under the recommended capacitors section - where the links are)

3 of 10uF
2 of 15uF
3 of 47uF
2 of 100uF
1 of 220uF

however, one of the 47uF is almost impossible to do yourself on this car, unless you are a pro, even I cuss when I have to do an SC400 - lol

 

Hey Guys, I'm hoping you can help a girl out. So glad I found this thread!

Hopefully a bad/failing ECU is (once again) the cause of my latest transmission problem in my 94 ES300 and not a bad/failing transmission. My ECU was replaced about 2 years ago with one I bought off of ebay ($100+), cause I researched online and found out about bad ECUs in these cars, when I was having intermittent hesitating and shifting problems - replacing ECU fixed it.

Last week I drove up from Sarasota to my dad's house in Atlanta (530 miles), where I'm now stuck with a car that won't move. A day or 2 after I got here the transmission started hesitating and slipping again (like it did 2 yrs ago), but this time it completely stopped doing anything after about 2 miles. Now it won't engage any gear. It just acts like there's no transmission.

I was researching online (again) and found this post. My dad and I went to pull-a-part to get a ECU to see if it would work just enough to get the car back to his house (it's still on side of road 2 miles away). We found 2 but neither of them worked. I know that a bad ECU is probably why the cars were junked (owners probably gave up trying to fix problems they didn't know was caused by bad ECU/caps), but I was hoping 1 might at least make the tranny work, even just somewhat, but there was no change in tranny with either of them.

Any input would be so appreciated!!

 

You might want to try posting this in the ES section. On the other hand, it sounds like you may be having an actual transmission issue. Not positive on that, just my opinion.

 

serious question, probably sounds like a smartass remark, but have you checked the transmission fluid?

I think I have a transmission troubleshooting guide for your year model of ES, if so, will post it later this evening (the cowboy is a night owl!)

generally speaking, even if the ECU is bad, has bad capacitors, etc - you can typically still manually select the gears

 

Hi Cowboy, yep the fluid was the first thing we checked. I did wonder about the manual shifting thing - I saw that on your list on first page. Not exactly sure how to manually select gears on an automatic.

There was something else I found out when I was researching before, and I wondered if it might be related to the issue I'm having now. There's a built-in behavior in this model/year (not sure about other models/years) where the transmission won't engage until it reaches a certain temp (something to do with emissions), so sometimes when the car is first started in cool weather it can take several seconds to a few minutes to engage, depending on how cold it is. I've seen a lot of people think something is wrong with their trans because of it.

Anyway, I wondered if whatever technology that controls that behavior is controlled by the ECU and (failing) ECU is maybe causing it to malfunction - never reach (or properly sense) the required temp, etc. My trans is acting like it's waiting to reach that temp but can't or doesn't 'sense' when it does. It won't engage or do anything in any gear.

If that behavior isn't controlled by or in any way related to the ECU, maybe a bad sensor, thermostat, etc? What do you think?

BTW, I've read this entire thread (all 30 pages!) and I realize that this may not help fix the issue I'm having, but I want to thank you AND Yamae on behalf of all 90s Lexus owners. This is a really awesome thing you guys are doing! Not just getting this info out there but (both of you) helping people (online and offline)... just because you guys want to help. I can totally relate. It's a passion of mine as well

 

a defective speed sensor can also cause this issue, the good news is that this Aisin transmission rarely ever fails with less than 200K miles, so if the mileage is lower than 200K, it is very likely something external. (i.e. low cost in a relative sense)

can you dump the transmission diagnostic codes? - I can post instructions on how to do this if you need them.

 

Looks like we posted at the same time lol. I responded to your first reply to me above.

Not sure about the codes. Maybe good idea to post instructions lol.

 

Oh and regarding defective speed sensor, I remember that being one of the possibilities I was told the first time I had tranny issues. It was replaced first, didn't help, then found out about bad ECUs and replacing ECU fixed it. So... now I wonder if it really is speed sensor or SOME sensor this time... and possibility both a bad sensor AND failing ECU - the replacement ECU does have the bad caps in it.

 

don't worry, I haven't crashed yet!

I have your factory service manual somewhere, trying to locate it now, it has a step by step set of checks you can make. - get the car home, and see if you can see the cable that is coming into the transmission physically moving the gearshift lever on the transmission when you go from 1, 2, D, R, etc.

PS - Florida is the most common state for bad ECU capacitors, must be some mix of heat, humidity or maybe that many Lexus's are snowbird cars, and sit up a lot undriven (not good for the capacitors)

 

I seem to recall that your year of ES300 was one of the first cars in the world to go to OBD-II codes, so you can just pick up a scanner at any auto parts store or walmart, in order to dump the diagnostic codes, or if you are going to be visiting your Dad for a while, then save a bunch of money by ordering this very good and very cheap OBD-II scanner at amazon


I am just referring to shifting into the various gears by hand, like you would a manual stick shift, rather than letting the car shift the gears - so to start out, you would move the shifter to the "1" position, and then once you are up to 15 mph or something, manually move the shifter to "2", etc.


this is incorrect behavior - the only thing that is supposed to happen temperature related, is that the transmission has a temperature sensor to keep it from shifting into the highest gear when cold, in order to speed up the warm-up time of the engine (to slow wear) and to get your heater to warm up sooner - so it is normal on a cold day for the shifts to be a bit later, and it doesn't want to make that final shift into high gear - until the car is warmed up.

however the transmission should engage immediately upon start-up, if the system is working properly and the fluid is at the correct level (you really cannot check it nearly as accurately cold, as you can when it is hot)

 

OK, something just dawned on me - an Aisin transmission that will not move in any gear is a very rare occurrence, and it is almost always very low fluid, and you said the fluid level is fine.

So I was racking my brain, where have I seen this before, and I remembered! - and this may very well be the problem, as follows:

sometimes when you get your transmission fluid changed, or if a previous owner got it changed, the shop saves money and doesn't typically use the real Toyota filter - these aftermarket filters rely on a friction fit, and sometimes after a while (could be days, months or even many years) the filter loosens and falls down into the transmission pan. - The filter has the fluid pickup built into it, and now the transmission can no longer pick up the fluid it needs in order to operate, and the car goes nowhere! - the transmission basically thinks it has no fluid, but it does! - it just can no longer reach its fluid!

easy fix, just change the fluid and filter! (and use the real Toyota filter)

not saying this is definitely the problem, but it is certainly one of the few scenarios that I have seen before, that would explain no motion in any gear, while fluid level is fine.

 

I think you're right! I suspected this too from the other research I've done, and because of the manual shifting thing you talked about (btw I figured that's what you meant about that before, thanks for the clarification). Anyway, the car is making a whiny sound kinda like when power steering fluid is low but different. You know what I mean? Doesn't a tranny whine when not getting fluid?

Thank you so much Cowboy! I think you just solved my problem. I had no doubt you could

 

problem solved. its under the glove box on the back of the lower dress panel..

ive only had a couple of the caps delivered so i went ahead and did them..

1 was definetly leaking. the other 4 didnt look that bad..

bad can confirm with what i have done.. man it starts so much easier now.. virtually straight off the key activating start.
instead of about a 4 second period of the starter turning over..

will keep you informed on the rest as it comes..

 

Cowboy, another quick question: With all the changes in fluid since 1994, which transmission fluid would you recommend we put back in it? I've found Dexron VII to be recommended most but wanted to see what you think. And I'm getting suggestions that a synthetic fluid like Mobil One being even better, but that my car wouldn't really benefit from a synthetic fluid at this point given its age. What do YOU think?

And 4 quarts correct?

 

there is no Dexron VII

Dexron VI would be my first choice, Dexron III my second choice, Dexron II was the factory fill

the number of quarts required is going to be dependent on how long you let it drain, the dipstick is the final arbiter, and the cold mark is a rougher guide than the hot mark, which is the precise level, but you can truly get the transmission how until it drives again! - 4 or 5 quarts should be enough to bring home, but I would start with about 3.5 after the filter change and keep topping up based on what the dipstick says (with car running in Park)

Get a Fel-Pro transmission pan gasket and make sure to use a torque wrench when fastening the 17 or so pan bolts

Filter bolts torque - 8 ft/lbs.
Pan bolts - 43 inch pounds

PRELIMINARY CHECK
1. CHECK FLUID LEVEL
HINT:
• Drive the vehicle so that the engine and transmis–
sion are at normal operating temperature.
Fluid temp. : 70–80 ? C (158–176 ? F)
• Only use the COOL position on the dipstick as a
rough reference when the fluid is replaced or the
engine does not run.
(a) Park the vehicle on a level surface and set the parking
brake.
(b) With the engine idling and the brake pedal depressed,
shift the shift lever into all positions from P to L
position and return to P position.
(c) Pull out the dipstick and wipe it clean.
(d) Push it back fully into the tube.
(e) Pull it out and check that the fluid level is in the HOT
position.
If the level is at the low side, add fluid.


NOTICE: Do not overfill.

2. CHECK FLUID CONDITION
If the fluid smells burnt or is black, replace it.

3. REPLACE TRANSAXLE FLUID
(a) Remove the drain plug and drain the fluid.
(b) Reinstall the drain plug securely.
(c) With the engine OFF, add new fluid through the oil
filler tube.

Capacity:
Total: 6.75 liters (7.1 US qts, 5.9 Imp. qts)
Drain and refill: 3.5 liters (3.7 US qts, 3.1 Imp. qts)
(d) Start the engine and shift the shift lever into all posi–
tions from P to L position and then shift into P posi–
tion.
(e) With the engine idling, check the fluid level. Add fluid
up to the COOL level on the dipstick.
(f) Check the fluid level at the normal operating tempera–
ture, 70–80 ? C (158–176 *F), and add as
necessary.
NOTICE: Do not overfill.

4. CHECK FLUID LEAKS
Check for leaks in the transmission.
If there are leaks, it is necessary to repair or replace 0
–rings, seal packings, oil seals, plugs or other parts.