joeparts11

Packrats chewed two of the injector harnesses on my friends '06 RX330. Both wires for cylinder injectors #3 and #5 were chewed through and left frayed. After repairing the wiring, cylinder #3 still does not fire. There is no ground pulse to fuel injector #3 from the ECU. The ECU pulse wire for cylinder 3 (from the driver in the ECU) is grounded all the time, even with the key off; it should not be. Both of the ECU repair companies I contacted did not work on this model of ECU. Does anyone know where the drivers for the fuel injectors are located in the ECU? I have tried to locate them with a meter, but been unsuccessful. I have attached a picture of the circuit board.
Thanks for any help.

HtownBlue

Look at the components on the board. Look for raised capacitors and burning damage to other components. Unfortunately without deep knowledge off electronics AND LEXUS ELECTRONICS you are throwing darts blindfolded in a sense. Might have to find a junk ECU from a yard and try that.

joeparts11

Thank you, HtownBlue. I think you are correct, and this message board is my last chance before buying another ECU. I have the support of a very knowledgeable electrical engineer, but as you mentioned, I don't have one familiar with Lexus ECUs. Installing a used one requires key reprogramming that I was trying to avoid. From my research on this model, it requires Techstream to program the key for the immobilizer system.

alchemist

iTrader: (1)

you could take it in to a dealership and hope you can get in front of a friendly lexus tech. I have done this before for something else. also, there are a couple lexus technicians on the forum. you'd have to search for them - they generally hang out in the GS forums.

alchemist

iTrader: (1)

off the top of my head TACH_MOTOR and VVT-i are members here and they are master technicians. send them a note.

joeparts11

Thanks for the response, Alchemist. I did send a private message to VVT-i, but was unable to do the same for TACH_MOTOR, as he had private messages blocked.
Regarding the local dealer, where the car was brought for insurance purposes to determine the actual financial damages, they wanted to remove the plenum for $450 so they could see if any other wires under it were damaged. It can be somewhat easily inspected with a mirror, furthermore, the only DTCs were for cylinder 3 misfire, not primary ignition. I had to argue with the service adviser who finally got the shop foreman involved so they could confirm the ECU was damaged, all this after I wrote up, in technical detail, why I knew the ECU was damaged. In other words, the local dealer is either inept and ignorant, or dishonest, hopefully the former.