could someone tell me what type of resistors these are or do I have to replace the board? the car is running way rich, a/c doesn't work, has trouble idling, and can only start moving in 1st gear, if I start in drive it feels like the tranny is slipping real bad. any help would be appreciated. ty

 

your ECU has leaking capacitors, please read my ECU capacitors thread, it will explain how to fix it!

 

sorry i forgot to put in that i had already replaced the capacitors that you had stated in your post. that is how found this one. sorry

 

For future posts, please post year of the LS in question. This is for your '93?
Did you check the contuinity on that resistor?
Was the board been cleaned/neutralized when the caps were changed?

 

That board looks pretty bad. Might need to get another ECU that is in better condition and replace the caps on that one.

 

Those resistors must be used to divide the voltages. The combination of those 4 resistors look just the same to me. I mean R231 with R201 makes one dividing circuit and also R232 with R202 makes another dividing circuit

R231 and R232 are 10KΩ and R201 and R202 are the same and are 62KΩ.

If I were you, I wouldn't to hesitate to use a resistor 62KΩ of 1/6W or 1/4W. For that much of big resistance only passes through less than 0.232mA maximum when 14.4V is applied. The ECU wouldn't be damaged with this much of small current.

What I worry about are the damages caused by the leaked liquid. There are many other items you have to do other than the resistor R202.

 

I agree, but even more importantly, these do not look like the caps recommended in the failing ECU caps post from Yamae and I

I keep seeing a recurring issue here on Club Lexus when you all decide to replace you caps, so please understand the following two issues:


● you need to only use the caps I have listed in the links in post #1 of the ECU caps thread, these are a very rare and specific type of low ESR, high ripple rejection, high temperature, long life capacitor. If you deviate from my recommended caps, I do not think the repair will work for you.

● you need to be very careful where you buy your capacitors, there are very few sources authorized by the four good capacitor companies, Rubycon, Chemi-con, Panasonic and Nichicon. - if you buy your caps from ebay, amazon, or some place online that is not listed in the factory authorized distributors at these manufacturer's website, then the capacitors you get are very likely Chinese counterfeits that look very convincing, they will not work correctly!


DO NOT rely on the guy soldering your ECU to supply the capacitors, they will be incorrect, YOU need to order them yourself!

places that rebuild ECU's, surprisingly, also do not use the correct type, I know, it is ridiculous and troubling!

 

It's just like when you bring your car to an independent mechanic and say "change my timing belt and water pump". Most wont use OEM parts, they'll use the cheapest they can find. That's one reason they are cheaper then the dealer, who does use OEM.

 

How hard to change that resistor? Isn't that as important as the leaking caps?

 

They are MELF devices and although you could remove and replace them with a conventional soldering iron looking at the state of the PCB print pads there will be nothing left to solder new ones to after removal of the old ones.
The resistors themselves will probably be OK ( check them in circuit with a digital multimeter) its the track/pad damage that will the problem.
I would seriously scrap that PCB and find a better example to upgrade.

 

Agreed.

we don't actually know if that resistor or its connection to the board is messed up, it doesn't look pretty, but I think incorrect type or counterfeit capacitors used in the repair is far more likely to be the current issue, rather than the resistor. It could well be both problems, a fair amount of the original solder pad has been eaten away, that board is likely beyond repair, I agree it is time to recap a nice condition one, rather than wasting more time on this one.

This should serve as a warning to those folks that think they can put off this time bomb lurking in all LS400, SC400, GS400 and most other pre-2000 Toyota models!