So, finally got a new ECU in the mail. Drove the car for a bit, cleared the codes, installed it, did the paperclip for 30 mins, started the car. Car started just fine (idled a little high but i didnt notice any other issues), codes still there. This time, instead of it taking a little bit for the check engine light to come on like it has normally done, this time it was immediate. Getting codes P0138, P0158, P0607, and a new one, P0630. I thought the paperclip fix would have prevented the 0630 but now i need to go get the vin programmed into the new ecu. I dont know what to do at this point.

Months ago i did start replacing fuses, but it wouldnt hurt to check again. Which ones do you recommend?

 

Check these fuses and this relay.

 

Appreciate you Lobux, this looks like a foreign language. Break it down for me, I see one Air fuel relay, 2 air and fuel fuses.

 

Could this be a wiring issue (short in the O2 circuit) that caused the original ECU to go bad? It wasn’t fixed and now the new ECU had gone bad as well?

 

At this point anything is possible, but I have no idea. I had Lexus verify that there's zero issue with the actual O2 sensors themselves, Toyota said it wasn't an issue with wiring and it was the ECU but clearly that wasn't right. With the old ECU the codes would take a few seconds to come on, but after warming the car up I could clear them and they stayed off. The new ECU it was immediate, but I haven't let it warm to temp cause I didn't know how far I could drive due to the vin not being programmed. Replaced the gas cap, no dice. I have replaced some fuses and relays but I'll try that again.

Should I be looking for a ground wire/screw somewhere? I have an aftermarket sub and I noticed the installer used a fuse extender/tap in the fuse panel under the dash...could that be it?

 

Do you think you can do this test? This is where I’d start.

 

Done. This isn't my area of expertise so let me know if I did this wrong.

Bank 1




Just to make sure, I switched the leads

 

No matter which way I had the leads, it never changed from Ol.

Bank 2

 

Actually, the picture I posted is of checking the sensors. I just looked at your original post, you've already replaced both sensors. I'll have to look at the test procedure for the car side O2 harness. You might need to probe between the O2 connectors in the cabin and one of the ECU connectors. Have you done the test at the ecu connectors that Lobux posted?

 

Im sorry I don't quite follow what you're saying. I disconnected the O2 sensors and that's where I did the checks is the two downstream sensors. Is there a different sensor you're talking about? Upstream?

I personally did not do the test that Lobux recommended but had Toyota do it and they said it was ECM. It could be that they didn't actually do anything and just charged me for it.

 

Yeah, you just tested the downstream sensors. Obviously they tested OK since they are new, sorry I didn't realize you already replaced them. Next step would be to test the harness. Unplug A6 connector from the ECU and check for short between terminals 1 and 3 of each of the O2 connectors (J94 and J95), and do a continuity test between each end of each wire (O2 connectors to the corresponding terminals on the A6 ECU connector)

 

I appreciate your patience in explaining this. I'm tracking that i need to test 1 and 3 of both bank 1 and bank 2 that are inside of the car, that makes sense. But, is the diagram saying that (for bank 1) that the wires that are attached to 1 and 3 at the O2 connection in the car end at terminals 4 and 26 of the ECU connector? and that 1 and 3 (on bank 2) end at terminals 3 and 27?

 

Correct, the reason you have to disconnect the A6 connector from the ECU is to isolate it and just check the harness or wires for short. Your meter should show OL or open when checking resistance between 1 and 3. Also test that neither wires are shorted to 4, Have you also looked into into your canister pump assembly? It looks like it's part of the system as well.