I'm in one of those situations you can't believe happened to you... I went on vacation a few weeks ago, left the car in the driveway (like it has been daily for the last 8-9 years). Came home a week later, and noticed the throttle didn't 'pop' like it usually does, it was fairly sluggish off the line. Then saw that the CEL was on, so took it to the dealer, and the code read knock sensor error. They inspected it and saw that a mouse had decided the space under the intake looked like a good place to set up home. And there was free lunch there too! My wiring and vacuum hoses that is.

I was in a pinch, so I ok'ed the repair. They suggested that since the car has 170,000 miles on it, it'd be a good idea since the intake was already off, to replace the knock sensors. After swallowing hard, I said to just do it. $1250 later I get my car back, running like it did before I went on my (now much more expensive) vacation.

I had it back home for 3 days, and noticed that the check engine light was back on again, so I assumed that they had knocked something loose while they were doing the repair, or maybe hadn't reconnected a sensor properly. I dropped it back off, and got a call the next morning, saying you aren't going to believe this, but it looks like that mouse had came back! They hadn't pulled the intake, but looked around under there with a flashlight and mirror, and it appears that it happened again. This time it would _only_ cost about $850. Only. On top of the $1200 I've already spent. At that point, I decided that, as they had already done the hard work for me (pulling it apart the first time, and breaking whatever was going to break during the removal), I was going to fix it myself.

They had said that the 1st repair had replaced some vacuum hoses, and repaired some wires. I called the parts dept, because I am not a fan of splicing and shrink tubing wires, I'd rather have new in there, if available and reasonably priced. Talking to the parts guy, he said that I would need housings and terminals, and make up new wires. I asked him about just replacing the top of engine harness, because I don't want to possibly miss a small nick that the rodent had made on one of the numerous wires under there, and a few years down the road have another CEL come on or wire corrode and break. He said that he would have to do some digging, but he didn't believe that they were available. I have yet to hear back from them, but does anyone here know if they are, as that would be ideal for me. Relatively quick and painless, except for my wallet of course.

I had just put about $3k into it about 7-9 months ago, including aftermarket cats, because my wife loves the car, and we're pretty much keeping it till the wheels fall off, or so I am told. So I'm pretty much married to it at this point. If anyone could pass along any info on it, or what they have done in a similiar situation with their LS400, I'd appreciate it. Also, comments/suggestions regarding any gotchas or things to look out for when pulling the intake, or doing the harness would also be greatly appreciated.

On a side note, I've gone full Caddyshack on this rodent. Well, almost. Sadly, no explosives, but I did hit the store and have bought about 15-20 enclosed poison traps, and have placed them strategically around the cars and front of the house, as well as near some trees next to the driveway. That rodent will rue the day he ever messed with me, and cost me about $1500 and a weekend of my time...

 

A junkyard or someone parting a car out would probably be your best bet.

 

If it were me I would find an LS in one of my local junkyards and get what I need from there. Or else try eBay. My best luck fixing my CV axle was a junkyard replacement and it's working fine.

 

the main engine harness is ~$1,400-1,700 USD. You're better off taking the car to a well reputed auto electrician (not dealership) and having them repair the damage.

 

I don't like mice or rats. I've seen them do some expensive damage to things. At least they didn't get in the car. I think the only place they could is in the trunk around the moon roof drains. I guess you don't have enough cats in the area, they do a good job keeping the rodents at bay.
If you want new wires you may end up having to either buy the connectors or use your old ones and make up the harness yourself. Just make sure you get some quality wire to do it. Hopefully not made offshore junk.

 

Yeah, less than fond of them myself, and if I can lay my hands upon it, you can be certain it will be an unpleasant ending... This has been an adventure in wiring harnesses, I've spoken to my dealer, and one from out of state that offers decent discounts on parts, which mine doesn't, and have had a hard time coming up with a harness part number for the specific one just for the part under the intake. The one I was hoping that they designed was a short harness which connects to the main one, still inside the engine compartment, and much less expensive than the part # we did come up with which corresponded to my VIN #, 82121-50410. Seeing as I have yet to pull the intake, I haven't been able to verify if this is the part I am hoping it is, but from the sounds of it it isn't, because even with a discount, that harness is about $1000, and looks to go thru the firewall with three connectors in the cabin, not a short top of the engine harness.

It may end up that I will have to have it repaired, again, but I won't know much till I get the intake pulled off. Anyone point me in a direction which might have some helpful info on the job ahead? Or even anyone who's done it before and can let me know of any gotchas to be aware of before I start the process, or anything besides the obvious (intake gaskets) that I should have in hand? Thanks again for the replies.

 

Have you checked with any recyclers? I see you headed down the path I went down with my CV axle. After trying a couple of $200 to $250 fixes I ended up with a $50 junkyard CV axle that works perfect and was in great shape. I'm betting you can find this harness in perfect condition for under $100 from a recycler.

 

Well, turns out that I am running into a time crunch with my backyard construction project, so I decided to contact a local shop that works on Lexus but whose rates are substantially cheaper. I ended up finding the correct harness, the one I listed above, and brought it in with the other stuff needed to complete the job. They pulled it apart yesterday, and found a lovely, cooked family of mice under there, I had a big grin on my face when I heard that. On the downside, the little shatz had eaten back the plastic connector on one of the 2 brand new knock sensors, so there went another $150... At least they were able to repair it again, and I sent back the harness to the out of state dealer for a full credit.

It should be done today, and since I now have the new LS400, I am putting this one up on the block. It hit craigslist yesterday, and have already had one, albeit a bit low, offer. I have the full service records from Lexus, and it's funny (sad funny) how you forget how much you have done over the years. I'm going to be pretty firm on the price, she's in great shape for her age and has had many of the more expensive parts replaced already.

Thanks everyone for your suggestions, I appreciated them.