Great thread so far, but I have some questions:
1. I had the MAF sensor and tube off of my LS430 last weekend as well as the throttle body tube. Cleaned both the MAF and TB, now it's time to tackle the knock sensor. Is it best to replace both as I have to remove the manifold cover anyways. I found a dealer on Amazon that has a nice price on a set of two.
2. Does the wiring harness really need to be replaced? I'm seeing prices in the $150 range.
3. I haven't been able to locate any video on replacing an LS430 knock sensor, mostly other models. Does anyone have video to share?
4. Finally, to those who have completed this job on their own...any "a ha" moments that I need to be aware of?

Thanks in advance. I really appreciate the posters on this forum. I've learned so much already.

 

This Youtube video (not mine), will show you how to get to the knock sensors...

 

Ok I did my knock sensors the other day. Its a mission to get the inlet manifold off without removing the injectors and fuel rails, but it is possible. I also managed to bend one of the gaskets, however, a bit of a tappy tap tap and a bit of hope/prayer, stuck them back in. Its not as crucial to replace those because the rubber centre is fairly thick and pliable so it'll still create a seal. If you know the starter motor hasn't been done before, then order 2 coolant bridge gaskets and a starter motor, because you will definitely want to. I pulled mine apart and all of the bearings were completely shot, and a field winding was starting to flap around in the breeze, indicating it was on borrowed time. The contacts, brushes and plunger were all in reasonable condition, but to rebuild it was going to cost $60 less than ordering a brand new one, and given the state of the field windings, it would have failed shortly anyway. The knock sensor loom and plugs are exceptionally delicate, mine fell apart in my hands, so I had to tape what was left of the plugs to the sensors. One other thing, go out and spend the money on a 14mm ratchet spanner for the starter motor bolts. You can thank me later.
The ECU wiring diagram I found did not line up to my model year LS, and I couldn't find any others, so trying to probe the loom for continuity was near on impossible. When refitting the vacuum hoses, it might pay to put the ends of them in boiling water for a minute or two to soften them up. The hose to the top of the inlet manifold was very hard and just kept splitting.

This did not cure my problem however. But I do have another theory. My l/f wheel bearing is very badly worn, and it makes a lot of vibration at any speed. Speeds up to 45-50mph was still noisy, but the fault code did not come back. Once I got above 50mph (for me it was 80kph) the vibration could be felt through the whole car. The harmonics this is making could be causing the knock sensor to generate an unusual signal, and this is confusing the absolute hell out of the ECU, causing it to outright go into limp home mode because it doesn't know what to do about it. I initially thought it was my rear bearings making the noise but I changed those and the noise is still there, so I have 2 fronts on order. Hopefully they turn up within the week.

 

Were you able to disconnect the main fuel pipe? I couldn't for the life of me and ended up disconnecting the fuel pulsation dampers and getting new gaskets for them instead.

 

Yeap, wasn't prepared to buy some oddball gaskets that would be near impossible to get. A 14mm and a 19mm was all I needed to disconnect the feed line. It was pretty tight though, but was free enough to not damage anything.

 

So I got the car all put back together with plenty of new gaskets, O rings, starter bits, brand new engine wire to go along with the knock sensors and the code for the sensors is gone!

Unfortunately I managed to cause some new problems. Once it started up it was running rough, the VSC check light came on as well as the check engine light. When I tried moving the car the parking brake light wouldn't go off and I'm guessing it has something to do with the brakes not working. Got techstream working on my laptop and these are the codes that popped up some of the C1200 codes came and went while I was checking it out.

P0115
C1201
C1221
C1223
C1241



I'm assuming something isn't plugged in the way it should be. I broke the coolant temp sensor while I was moving the intake around. I hope I didn't break anything else to the point that it'll have to be replaced. I'll be spending some time on google trying to pinpoint the source of these new issues wish me luck

 

I busted off the plug for the temp sensor in the same way you did, but I ditched the plug, put two small terminals on it, attached it directly to the pins and filled the plug full of urethane sealer. That is what your P0115 code relates to. Your C-codes relate to wheel speed sensors, ECU malfunction and low battery voltage. Go over all your plugs again, make sure they're all plugged in properly and seated correctly. The wheel speed sensors are an odd one to crop up though. My knock sensor fault has not been fixed unfortunately. The code for the bank 2 sensor has now been replaced by the bank 1 sensor (both were replaced btw) and I'm getting a P0325 code, but it only throws the code at highway speed at roughly 50mph. Its got me stumped as to why it does it there and not at lower speeds. If it was a dead short somewhere, the code would come up all the time, not just at cruising speed

 

I really couldn't say but maybe it's the wiring that's causing your code since both sensors are brand new.

That low voltage code is the one that doesn't want to go away for me I changed the alternator after it first popped up and O'rileys said it had tested bad. Came back soon after that so I thought it might be related to the knock sensor codes that kept switching back and forth between bank 1 and 2 like yours so I spent the extra $200 for the Postive Engine wire no. 2 since it was such a beast of the job to get to the senors in the first place. Now it's back as soon as the car had been started again so neither of those fixes have helped. The car really isn't in any shape to drive the way the brake system has gone into failsafe. I thought I was going to run into my neighbors yard when I first pressed the brakes then they locked up hard and the sound was not pretty.

That's quite a mcgyver you pulled for that temp sensor I tried to just stick it back in place hoping it'd still get a connection. Should've tried your method but I already hit submit for a $40 new one on ebay. I'm really not looking forward to trying to hunt down what I hope is a simple mistake because I'm sure there's more than one waiting to be discovered. When I started putting everything back together I figured I'd get a code letting me know what I messed up once I got the car started I just didn't think they'd be so vague. I've found the service manual online and the endless diagnostics seem pretty exhausting. I'm starting to wonder how much it'd end up costing me to just get a tow and let a shop set things right at this point.

 

It is likely that your car battery voltage is too low. Disconnect the battery cables and fully charge the battery to see if the DTC would stay off.

 

Battery is fairly new and is at 12v right now though I don't have any way of charging it at this time.

What I'm really worried about right now is why the VSC off light is coming on and stopping the brakes from working. I went back over all the plugs and they all seem good.

 

When you say that the brakes don't work, do you mean pushing on the pedal literally results in zero braking effort? Or that they 'basically don't work' and just exert minimal braking compared to the amount of force on the brake pedal?

 

The brakes seem to have gone into a failsafe mode or something
When I pushed the pedal it was 0% brake force or 100% once I pushed the pedal all the way to the floor. I talked to a mechanic friend of mine and they mentioned I could've put the brake booster vacuum in the wrong spot. He's coming over tomorrow to take a look.

I'm still working to figure out what's causing these issues if anyone has a picture of their engine without the cover that'd be helpful. Not sure where I messed up but I know I'll be taking more pictures next time.

 

That does sound like it could be a vacuum issue. Either a line disconnected or in the wrong place, or the booster itself has gone bad. My VSC light came on in my 2001 a few hours after picking up my car from a shop that was doing some work under the hood. One of their techs actually drove out to where I had pulled over on the side of the highway a few miles from their shop and found a vacuum line that had slipped off of it's nipple/sleeve thing because it hadn't been pushed on quite far enough/not secured. He plugged it back in, cleared the DTC, and had no further problems after that.

The other thing I can think of is maybe the ABS accumulator or actuator...?

 

The brakes definitely sound like you've got a vacuum leak. Check the main hose to the booster it put back in its place on the manifold. We had that problem with my partner's VR4 Galant wagon and while the hose was on, the hose had a check valve in it and was fitted bass ackwards so 0 vacuum was getting to the booster. I literally had to stand on the pedal to get any stopping action going.

Currently I'm still getting a P0325 code, I tried doing the splice mod on both wires but I'm still getting codes. I'm going to read the codes I have tomorrow, and have one more shot at getting this wiring mod right before I rip the manifold off again. The wiring loom I currently have is in no state to be struggling with the manifold more than I already have.

 

So the $30 Coolant temp sensor came in today from amazon. Installed it with a new gasket, engine started right up and run's without the VSC or check engine light returning. Unfortunately the BRAKE light still doesn't go away after I take off the parking break. The brake's really don't have any travel to em even when the engine is running.

When I plug in Techstream I got a few codes but once I cleared them none returned. the The vacuum line going from the intake to the brake booster seems to be on right but I don't know how I could test it. I removed the hose and put my finger over the pipe from the intake whilie the engine was running and it did have suction. I'm starting to think this is a problem with the brake booster I just can't figure out why it suddenly went bad after I replaced my knock sensors.
Found this picture and the car failed the first two checks.

Any got any input on this situation? Should I go ahead and start looking into replacing the brake booster assembly?