Thanks for taking a look. It doesn't look too bad, when compared to ones i've seen. Looks like a small amount leaked.
KZJ78 Tigris Writeup: ECU Rebuild/Upgrade with Pics
- Thread starter Tigris
- Start date
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- Thread starter
- #42
No problem!
I agree. From these images I can say with good certainty that the ECU is likely repairable. (BTW it appears to have been repaired at least once before, judging by the non-standard caps in the first photo). I don't understand why would the ECU repair shop deemed it unrepairable.
I am in town until early May. If you want, I can work on this ECU for you. Send me a PM if you like. But only If you can find the caps I listed in this thread in stock at digikey first. These caps go on back order frequently since they are the coveted low ESR ones.
Cheers!
- Thread starter
- #44
@Rawloh44 ,
At the moment I don't have an ECU handy, but if you were to get the markings on the diodes there is a good chance of finding the appropriate replacements, diodes are also less finicky than other components, but only the correct replacement should be used.
Some things to consider:
You may already know, but sometimes we can get a faulty reading on a component on a board caused by a different component located elsewhere in the circuit. Have you tested the diodes out of circuit? Maybe corrosion or damaged traces are triggering the fault reading. Just a thought.
A shorted trace or a shorted component (in parallel with the diode can also give a false reading. Diodes can certainly fail, especially if they get overloaded by another fault nearby or get exposed to corrosive electrolytic solutions. If you haven't tested them out of circuit, do so, you will also be able to read the markings better this way.
Best of luck!
At the moment I don't have an ECU handy, but if you were to get the markings on the diodes there is a good chance of finding the appropriate replacements, diodes are also less finicky than other components, but only the correct replacement should be used.
Some things to consider:
You may already know, but sometimes we can get a faulty reading on a component on a board caused by a different component located elsewhere in the circuit. Have you tested the diodes out of circuit? Maybe corrosion or damaged traces are triggering the fault reading. Just a thought.
A shorted trace or a shorted component (in parallel with the diode can also give a false reading. Diodes can certainly fail, especially if they get overloaded by another fault nearby or get exposed to corrosive electrolytic solutions. If you haven't tested them out of circuit, do so, you will also be able to read the markings better this way.
Best of luck!
Malleus
Far west of Siegen
FWIW, I recently discussed repair of '90s era ECMs with Circuit Board Medics, in Greenville, SC. They repaired a board for me, for another application, and I was very pleased and impressed with the service. While they only list RAV4 on their website, they tell me that is because they have only had requests for that model's ECM.
I can also personally recommend @Engineer8000 in Southport, NC. He recently repaired a board for my 40 ignition module.
I can also personally recommend @Engineer8000 in Southport, NC. He recently repaired a board for my 40 ignition module.
Any update on these? I need the exact same one in same spot.
- Thread starter
- #47
Looking at this picture, I believe that the blue component c002 is a mica capacitor. Typically those are very reliable and require no replacement unless they are damaged by the surrounding electrolytic. The value can be verified by pulling a similar but functional cap and measuring its capacitance out of circuit using a capacitor tester. They are also cheap and not super critical in this portion of the circuit (likey used for coupling purposes).
Cheers.
Just as Tigris mentioned I used a multimeter to test them as diodes and compared them to a working one on the other side of the ecu. I forgot what i measured on the multimeter, but i replaced them with this part number on the mouser electronic website. 625-1N4007E-E3/54. Just have to make sure you install them the right way.
Alright. I think I'll try that diode you mentioned. The only markings on all these ones is a blue L. I really have no clue how to find the replacement diode.
GTSSportCoupe
2LTE abuser
Guys, those diodes are likely to be fine. The stuff on them is dielectric from the failed adjacent electrolytic capacitors.
The problems you'll find even if install new capacitors, is the dielectric is corrosive and can damage the copper of the circuit board: eroding it away completely. The board needs to be carefully cleaned and inspected under a microscope. I repaired a couple of these before, and had to run small gauge wire to repair the open traces/vias.
As mentioned, you can test the diodes with a DMM in diode position. In one direction you should see about 0.5 to 0.7V drop, in the other direction it should read high impedance. Technically you should be doing this measurement with the diode out of circuit. (because when you measure in circuit, the rest of the circuit elements may impact the measurement). But don't try to remove them, as you'll likely damage the PCB without using right tools. As mentioned, I'm confident they're fine anyhow.
The problems you'll find even if install new capacitors, is the dielectric is corrosive and can damage the copper of the circuit board: eroding it away completely. The board needs to be carefully cleaned and inspected under a microscope. I repaired a couple of these before, and had to run small gauge wire to repair the open traces/vias.
As mentioned, you can test the diodes with a DMM in diode position. In one direction you should see about 0.5 to 0.7V drop, in the other direction it should read high impedance. Technically you should be doing this measurement with the diode out of circuit. (because when you measure in circuit, the rest of the circuit elements may impact the measurement). But don't try to remove them, as you'll likely damage the PCB without using right tools. As mentioned, I'm confident they're fine anyhow.
