mikebatman

in an effort to save money i've taken it upon myself to carefully remove my ECU for inspection.
i am sharing a couple photos to confirm and validate my effort.
after a thorough inspection of all 8 capacitors it appears none are sick or leaking onto the board.
i did not want to put too much stress on the ribbons so i only opened the top board as far as i was comfortable.
i am going to re-assemble everything after i post this.

this was an effort to confirm the cause of my constant simultaneus check engine light and traction off light.
one of my terminals to my battery is corroded. so i will be cleaning that after everything is re-assembled. is it possible the corroded terminal is hindering power to my vehicle thus causing the check engine and traction off lights? i will soon find out.

much thanks to LScowboy and his thread for inspiring this effort.

LScowboyLS

your ECU appears to be a virgin!

keep in mind, that these Nichicon PF (M) caps, in the early stages of going bad, show no visible problems!

our guru Yamae recommends that they be replaced as a preemptive measure.

I know on my 96, I started having issues, I then inspected the ECU, and everything looked top-notch and perfect, so I put everything back together and continued to search for the source of my issues for about 3 or 4 months, and then forced myself to go back into the ECU to reinspect, and to my amazement, the caps had subsequently not only leaked during that 4 months, but had already seriously damaged the board from the leaking electrolyte's caustic effects, like someone had spilled acid on the circuit traces, I caught it just in time to save the board!

and yes, be careful with the gray ribbon cables, they will take some degree of flex, what is necessary to fix the board, but any rough treatment and you will have a real mess on your hands trying to reattach them!

as far as the battery terminal, I strongly recommend you not just clean, but actually replace the end of the positive one, it likes to built up corrosion in areas you cannot see visually (under the bolt about 2 inches down where it attached to the cable) - you can pick up a replacement at any Toyota dealer for around $14 or so, this positive cable end is used on dozens of Toyota models, so they will have it in stock.

mikebatman

Okay, so it is likely still the caps even though they look mint.
I just finished getting everything back together and cleaned the terminal.
Not only was it badly corroded but also quite damaged.
I will definitely replace this tomorrow as nothing in open today.
For a brief moment after starting her back up the check engine and trac off light stayed off!
But only a moment later they came back on lol
However slightly delayed in relation to before.

Regarding replacing the caps.
It is definitely not something I'm willing to risk.
At the moment it is something I'm not sure how to approach as any direction is costly.
I will consider my options.
At least now I know how to take it out and can save myself Labour costs.

LScowboyLS

definitely replace the positive battery terminal with the real Toyota one - $14 or so is not that much for such an important component - just bring the old one to the dealership so they can match it, but most Toyota models used this same one for years - if you tell them that you have a business fixing Toyotas on the side, any dealership should give you at least 20-25% discount off of parts

Yamae

Did you read codes?

When a capacitor is aged, the increased ESR and the decreased capacitance cause variety of problems. The capacitor looses capability to reduce ripples and noises.

One problem is that sensors begin to send abnormal signal to the the processor since the supplied DC to sensors contains ripples and noises. The extra amplitudes are added on the pure signals. The processor is confused by those abnormal signals as well as the processor it self malfunctions.

At the early stage of the failed capacitors, the car still runs mostly well but begins to show intermittent problems turning the engine check light on. You can read codes at this stage but those codes obtained are not related each other in most of the case. That is why I ask you, "Did you read any code?"

As capacitors increase the ESR more and decrease the capacitance more and exceed the threshold level, the processor enters the safe mode and the engine only revs up to 2000rpm.

Electrolytic capacitors dislike high temperature conditions. You can expect longer lifespan of them since you live in Canada. But don't expect to those Nichicon PF(M) capacitors too much. Those are said to be a phantom as I have introduced at LScowboyLS's capacitors thread.

mikebatman

@LScowboy
I will definitely replace the positive terminal in the next day or 2.
I may have to wait until Tuesday this being a long weekend.

@Yamae
Unfortunately I do not have a code reader, so I am not able to verify the code that is triggered.
I have had this vehicle for 7 months and through the winter despite these issues never had a problem exceeding 2000rpm.
I am currently looking into my options for having my capacitors replaced.
@Yamae
Something LScowboy mentioned I should ask you regarding my mass air flow sensor.
In the past several months I have had erratic idle and stalling at low rpm.
3 months ago had my maf sensor replaced with much improvement however still fluctuates slightly in park between 600-800-1000. Still under warranty. Fuji electronics.
Is this acceptable maf sensor?
And what is required to calibrate the maf sensor?
Thanks

Lavrishevo

iTrader: (1)

No calibration on the maf.

Yamae

Codes can be read easily without a scanner on your LS400 as is explained
here.

Regarding the MAF, without observing the waveform myself I have no idea to judge. Why don't you try another one since yours is still under warranty.

mikebatman

Awesome, I will experiment with the code reader on my next opportunity.
And I will definitely order the other maf.