BlackWorksInc
New member
Best of luck, please let us know how it works; pictures would be awesome too! Even it ends in failure, at least we have a record that someone did go through the effort.
** Need Help, 4Runner won't start
- Thread starter dglee
- Start date
Best of luck, please let us know how it works; pictures would be awesome too! Even it ends in failure, at least we have a record that someone did go through the effort.
Out of curiosity, why have you ruled out getting a used ECU? It isn't a part that's subject to much wear. Either they work or they don't so I don't see how you can go wrong getting one mailed to you from a salvage yard that provides a 30 day guarantee. A quick search on car-part.com shows that you should be able to get a replacement board shipped to you for less than $100.
Last edited:
Actually, I did price out a used one, but then I would have to take (tow) the vehicle in to the dealership to reprogram the ECU for my keys (security, immobilizer, transponder) to see if it would work. But I know I have other issues (VSC & ABS - earlier in my posts) that might still prevent it from starting. Then I'll be stuck there at the dealership and at their mercy. I'd rather be stuck in my driveway and just tinker at my own speed.
You can actually reprogram the computer to recognize your keys yourself without taking it to the dealer. At least you can when you lose a key or want to add a spare. I've never done it with a new computer involved but you may want to research it and see if anybody else has. No tools necessary, just a really strange series of opening the door, shutting the door, turning the key, and so on.
Good luck with your issues. I hope that you can get them figured out. I've been there.
Good luck with your issues. I hope that you can get them figured out. I've been there.
I am glad to hear you at least found your problem, but I am sorry to hear its the ECM.
I would think chances of finding documentation on a level that would identify something as specific as a diode would be slim to none. However, you should be able to identify it by looking at a board that is good. Would you be able to get someone to send you a picture of a good board?
The problem I have found with repairing unrelated circuit boards in the past is that components that show visual signs of damage are often a symptom of the real problem, not the cause. You may successfully repair it only to find you toast another one. Troubleshooting can be difficult without a thorough understanding of the circuitry.
But, you don't have much to lose giving it a try. Worst case you still have a bad ECM.
I would think chances of finding documentation on a level that would identify something as specific as a diode would be slim to none. However, you should be able to identify it by looking at a board that is good. Would you be able to get someone to send you a picture of a good board?
The problem I have found with repairing unrelated circuit boards in the past is that components that show visual signs of damage are often a symptom of the real problem, not the cause. You may successfully repair it only to find you toast another one. Troubleshooting can be difficult without a thorough understanding of the circuitry.
But, you don't have much to lose giving it a try. Worst case you still have a bad ECM.
DanielMaat89
New member
Another quick thought, Zener Diodes are typicaly used as protection devices and in power supplies to generate reference voltages. Certain sensors require a reference voltage to operate correctly. Sensors like the TPS and MAF sensor for example use a reference voltage that is constant so the ECM can accurately read the signal coming from that particular sensor. I would get a service manual with the pinouts of the sensors and try that. If there is no reference voltage, the ECM cannot read data from the sensors and therefore cannot control the ignition timing, injectors and the VVT actuators. Can you connect a scan tool and read any data?
Update: Having no luck in identifying the blown part in location D409. Did get to actually talk to a Toyota Technical Region Rep, but no dice on the schematics or component information on the part. Apparently, this is still proprietary which "is still in Japan". Was suggested to purchase a used ECM to at least get the engine cranking again. I'm still on the fence about a used ECM. Noted my disappointment to Toyota Corporate, no response after two days. Even though I have other issues besides the cranking issue, just got frustrated that Toyota would just leave their customers high and dry. Just vetting here folks. Oh, BTW, scan tool cannot communicate, no link.
