nedogre20

I would like to start off by saying I'm new to this forum and have been here many times to look for help on diagnosing my problem so I figured it was time for me to contribute. This was a lengthy electrical nightmare that started August 2nd and finally ended today, September 2nd.

Back in June I went to drive my SUV to grab some dinner and realized there was a loud whining noise and a burning smell so I turned around and went home to get a different car. I feared it was the timing belt because its the original belt to the car with 133k on it. In mid July I changed the timing belt, water pump, cam and crank seals, the tensioner, both belts, the pulleys and flushed the coolant while I was in there. After I put it all back together the whining noise was pretty much gone so I thought I fixed the problem by doing the timing belt service.

I drove the SUV around for a few weeks with no problems then I went to start it up on Aug 2nd and it would crank but not start. The car died in my garage so I immediately started to diagnose it. I hooked up my bluetooth scan tool and it gave me:
P0123 Code - Throttle Position Sensor/Switch A Circuit High Input
P2135 Lexus - Throttle/Pedal Position Sensor/Switch 'A'/'B' Voltage Correlation

I thought to myself how in the hell would the throttle position sensor and the accelerator pedal position sensor die so randomly. I didn't have the time to mess with it so I towed it to my local Toyota dealer here in fort worth for a diagnostic. The service adviser called me and asked me if the battery has ever been installed backwards because his scan tool was reading the same codes but the technicians software also showed him something to prove othewise. I drove to the dealership and he told me the codes sound like they are related to the CSP (customer support program) and that Lexus should cover the costs for the tow and the replacement parts.

So I called Sewell Lexus who offered to tow it from the toyota dealership to theirs. I get a call from the service adviser at Sewell Lexus to tell me the ECU is fried and the wiring harness needs to be replaced and the total job would cost $6,000!!! I told him don't touch it and I will be there after I get off work. Not sure if I'm posting the pic correct or not but here are the pics:











Sewell Lexus in Fort Worth has tried to screw me before so I wanted a 2nd opinion before I made my decision on what to do. I towed it to a shop that only works on Toyota Lexus or Scion cars only and he confirmed the same diagnosis. He wanted 4k to replace the ECU and the ECU harness so I paid him for his time and had the SUV towed back to my house to start work.

My first order of business was to look for a used ECU (with the exact part number) and I was able to locate one at a salvage yard for $150 which I thought was a good deal considering the guy could get it next day. Not knowing the ECU needs to be reseeded to the current VIN, I snapped in the new ECU and attempted to start the car with no avail. I made the decision it was time to suck it up and remove the entire ECU wire harness before I bought the new one. I removed it and ordered the new one which took a week to arrive from Japan. I ordered it from lexus of south Atlanta as they were $700 cheaper than sewell.

So many items had to be removed to access the wire harness so I decided to go ahead and replace the spark plugs, plenum gasket, pcv valve and thermostat. It took me 1 day to remove the old harness and another day to install the new one. Still not knowing the ecu needs to be reseeded to the current VIN, I attempted to start the car and it would crank but not start. I plugged in my scan tool and it gave me B2799 which is the immobilizer. The immobilizer will not allow the car to start if the VIN is not recognized. It will not allow the fuel injectors to fire hence the stalled car. I called the service adviser at toyota and he said he could reflash the ecu to the current vin for $200 so I had to have it towed AGAIN from my garage to the dealership. The technician told me it started up on the 2nd try and it smoked so bad (from the engine being cranked over so many times) that he turned it on and moved it outside to let it idle so the technicians don't inhale all that smoke.

I waited at the dealership while they reflashed it and as soon as I walk up to the car to see it idle, the whining noise is stronger than ever. The technician tells me its the alternator and its about to die so I quickly drove it out of the service bay to the parking lot where it dies. My brother comes to the dealership to see if we can jump it to get it home and it barely made it there. We replace the alternator that night and the whining noise has gone away completely. After dealing with all that crap the past month, I thought I was done and could begin to use it as my daily driver again. NOPE!!! As soon as I turn the key to the ON position, the radiator fans begin to spin at the highest setting without the engine running. Tested the coolant temperature sensor and it was good. Replaced the thermostat. Made sure the coolant was topped off. Checked the 1 relay on the drivers side and it was good. All that was left was the cooling fan computer which was showing 0 ohms. My entire family buys lexus so i was able to swap out the cooling fan computer with my sisters and it immediately solved the problem so I ordered a used one of a website and it solved the problem of the radiator fans spinning out of control. Here is the part number for the cooling fan computer: 89257-48020.





FINALLY......after going to hell and back with this thing, its back to my daily driver today. If anybody has any questions regarding this post, ask or pm me and I'll do what I can to help. Thanks!!!

ericg

Glad to hear that your nightmare is finally over,
Did anyone ever determine what caused the initial failure of the wiring harness and ecu?

nedogre20

No I never determined what caused the initial failure. The techs at Lexus tell me they never see a failure like this unless a rat chews thought the wires.

ericg

It must be so frustrating that there was a definitive failure of one or more parts of the electrical system and no known cause. It will be interesting to see if anyone else posts a similiar situation.

nedogre20

I got several CEL codes so I knew there was no way that everything could've failed at the same time. The brown ground wire in the picture melted together with another ground wire in the harness underneath the plenum. The harness could have been fixed but it wasn't worth it considering the price difference. I made a few phone calls and got quotes around $600 and a new one was $1200 from Lexus of South Atlanta. After taking out a defective harness, the last thing I wanted to do was reinstall it. I just had to bite the bullet and install a new one.

Eliaquim

Hello!

I know this is an old thread,but if you are still around, I would apreciate your help. My engine wire was cut in half and I would like to know if you kept your old engine wire so you can help me with some pictures. At the moment I cannot import used parts and a new one is very expensive due to exchange rates. So I am thinking about soldering.

Thanks in advance!

nedogre20

I'm not sure If I kept my old wire harness or not. How did your harness get cut in half???

Eliaquim

I found the harness like shown in the picture Don't know the reason. Either a hater or someone was trying to stea the wires for the metals. Chinese are buying copper and alluminum and other metals.

Quatro40

Someone doesn't like you.

Pdawilson

Goodmorning
. Can anyone advise on how to replace the keys and ignition in a rx330 ..
I have this suv and the security system was condemned. I bought the ignition and keys and wishing to install ..
problem with the car : it drives good for two weeks then it will tumble but not start .. if you turn the keys two days after it starts only to get the two weeks driving good then no start again

Benito74

Hi there! I have a 2005 Lexus RX330 that I got from auction as a theft recovery. Its starts for a second and then dies. Do you think computer for sure? I would appreciate any help