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Yamae- Have you seen or heard of any failed electrolytic caps in the 98-00 LS400's? I have 2 LS400's, a 97 & a 00. All caps had been replaced on the 97 a few years ago as a preventative maintenance but I haven't touched the 00 as I live in California with very mild weather. The car also only has 50K miles & it still drives like a brand new car w/ everything working flawlessly. My last conversation w/ you about 2 years ago, you had indicated Toyota had used better caps for the 98-00 so if mine doesn't acting up then there's no need to replace them. Is this still the case? Please advise. Thanks.
Yamae- Have you seen or heard of any failed electrolytic caps in the 98-00 LS400's? I have 2 LS400's, a 97 & a 00. All caps had been replaced on the 97 a few years ago as a preventative maintenance but I haven't touched the 00 as I live in California with very mild weather. The car also only has 50K miles & it still drives like a brand new car w/ everything working flawlessly. My last conversation w/ you about 2 years ago, you had indicated Toyota had used better caps for the 98-00 so if mine doesn't acting up then there's no need to replace them. Is this still the case? Please advise. Thanks.
I myself have experienced 2 failed ECUs for the VVTi engine model (manufactured after July 1997) while helping several shops and even 2 dealers. Both showed strange AT shiftings. Every capacitor was not leaked yet but some showed a bit higher ESR. Replacing all those capacitors fixed problems completely. Other than those 2, A European member named silos5 from Tallinn Estonia had experienced the similar problem. See the post. https://www.clublexus.com/forums/ls-...ml#post8173285
I don't think the capacitor manufacturer Nichicon did anything new. Only the ECU design was totally changed using newer processors that run faster but consume much less energy using a narrower semiconductor design rule and ceramic capacitors used together with Nichicon's QAS capacitors were newer and had lower impedance and ESR. These reduced the stress to Nichicon's and those are the reasons why Nichicon capacitors of PR(M) or PF(M) were not killed quickly compared with earlier ECUs. Newer design and good ceramic capacitors helped to extend the lifespan of those Nichicon QAS capacitors, I bet.
I don't think you need to replace them ASAP. Of course it would be better to do so as a preventative measure but it's all up to you.
So improvements in the design helped reducing power consumption in the 98-00 ECU's thus putting less electrical & mechanical stresses to those caps. As a former Senior Scientist at an Aerospace company specializing in Communication Satellites, when it comes to design, I've always paid attention to the circuit/component's bias points & kept each component's derating at 50% or lower so what you've mentioned, makes perfect sense.
Btw, in LSCowboy's 1st post, he listed a total of 11 caps for the 98-00, however in his subsequent posts, he only mentioned 10. Can you tell me if any of these 10 or 11 are ceramic or are they all coaxial electrolytic caps? As you know, the ESR (Equivalent Series Resistance) in the ceramic caps, by design tends to be much more stable over time than electrolytic caps so perhaps that's why he stated "Replacement Recommended" on a few of them instead of it's a must to replace them all so would you please clarify on this. You're very knowledgeable when it comes to electrical issues on these cars & such a great contributor to this community so thank you very much.
There are 11 electrolytic capacitors but one is a bipola one. Ceramic capacitors are many there. You don't need to do any for them since they are very stable and last almost forever except defective ones such as the internal short circuit, corroded, cracked and etc.
Ok, so all 11 are electrolytic caps. I had given the 00 LS400 to my oldest son last year but I'll place an order for these caps. When he decides to do it as a preventative maintenance, I'll pull it out & fix it for him. Thanks again for your confirmation. Have a great day.
Ok, so all 11 are electrolytic caps. I had given the 00 LS400 to my oldest son last year but I'll place an order for these caps. When he decides to do it as a preventative maintenance, I'll pull it out & fix it for him. Thanks again for your confirmation. Have a great day.
You indeed are a nice father. Your son must be happy having such a kind father. Hope your replacement job will be going well.
There are 11 electrolytic capacitors but one is a bipola one. Ceramic capacitors are many there. You don't need to do any for them since they are very stable and last almost forever except defective ones such as the internal short circuit, corroded, cracked and etc.
Thank you for all the info so far. I have a question on one of my surface mounted components. It looks like the capacitor leaked out onto the board and is there anyway this can still be repaired
You should clean the PWB (Printed Wiring Board) first then do a visual inspection to see the condition of all the signal traces (signal transmission lines) in that area. If some of the lines look iffy then check the continuity of each of the signal line by putting the voltmeter's probes (set in Ohm) on both sides of the line where you think it may have been etched (ate away) by the acid. If it's open & it's on the top layer of the board then you can repair the line by soldering a metal jumper across it. If the PWB is a multi-layer board & the inner signal trace(s) is/are damaged then it's deemed beyond repair so you'll need to acquire a new ECU. Get one from a local junkyard or check on eBay. Best of luck.
Thank you for all the info so far. I have a question on one of my surface mounted components. It looks like the capacitor leaked out onto the board and is there anyway this can still be repaired
A extremely skilled guy would repair it seeing the photo below if the internal layer was not damaged.
I believe the ceramic capacitor C102 is connected to 2 separate pins of IC106. Finding out those 2 pins carefully checking the remaining traces after the intensive cleaning, I'd try connecting 0.1uF/25V to them at the other side of the board other than replacing all QAS capacitors. It will be a time consuming job.
Last edited by Yamae; 09-07-20 at 07:02 PM.
Reason: To add my actual way to repair
Hi Guys, I wanted to chime in regarding by 1992 winnebago warrior built on a 1992 pickup chassis. I found this thread researching capacitor leaks on toyota cars. Of the list on the first page, my RV is experiencing the following issues:
● problems in getting into diagnostic mode or scanner says "no communication" - When shorting the TE1 and E1 terminals, the CE light does not flash rapidly like it's supposed to with no code stored. It only does so when it's cold.
● engine runs like crap, then suddenly runs fine again - The engine runs fine for the first few minutes, then runs rough and misfires after warmed up.
● low idle or erratic idle
The timing mark on the crankshaft pulley is also dancing around and not consistent. When looking at spark from the distributor, it seems there are always 1 or 2 ports not giving spark. The engine is misfiring when warmed up.
We took apart the ECU with my mechanic, and discovered the following capacitor faulted and leaked. I just wanted to get your opinion on if this is what's causing the issue. We have already replaced the distributor, ignition control module, and igniter assembly. I am waiting for a replacement ECU from Flagship One.
The main function of these electrolytic capacitors is they're used as by-pass capacitors in electronic circuits to filter out signal noises/ripple voltages riding on the DC (Direct Current) lines. These capacitors contain liquid electrolyte which is a conductive sulfuric acid that's why these capacitors got its name from. Once leaked, the acid can etched (ate away) the PWB (Printed Wiring Board) & signal traces which made out of polymer & copper materials, respectively. When it's too severed i.e in the case that part of the signal trace's copper had been etched through completely, it'll cause the signal trace to open up thus prevent the electrical signal from propagating/passing through. As mentioned previously, if the damage is on the board's top layer then there's a good chance that the board can be saved by performing electrical repair. One can solder metal wire as jumper across the damaged trace to re-connect the signal, however if the damage is on the inner layer then there isn't much you can do but getting a new board. Anyway, vehicles now these days are computer controlled which heavily utilizing the ECU (Engine Control Unit) as its main central processing unit. When it's compromised & depends on which part of the circuit/function is compromised, once identified and properly repaired, there's a very good chance that you can get your vehicle back to its "should be" & good as new condition.
Thanks for your reply. I wanted to ask you, does the capacitor in my image I posted look bad like it could cause stalling, and rough idling/misfires?
Regards,
Winnie owner[/QUOTE
Yes, it's definitely leaking & based upon what I saw from the photo, some of the signal traces may have been damaged. Like I've said, depends on which circuit(s) & function(s) those signal traces are part of, you could very well experienced those symptoms.
08-23-20, 11:47 PM
