1994 3.0 knock sensor wiring harness to ECM

Hello , I just purchased a 1994 4runner for my daughters first vehicle.
I had to trailer it home as the previous owner could not make it run..
I have got it running and have the code 52 knock sensor.
I unplugged the sensor wire under the intake boot and noticed the wire that runs in the injector harness was cracked and the inner wire was touching the shielded outer wire. I repaired it and still get the 52 trouble code. I am thinking of just replacing the wire all they way back to the ECM.
Has any one done this ? If so I removed the ECM but can not locate the knock sensor wire. Looking at the 3 connectors that plug into the ECM I do not see a shielded wire at all. I assume it becomes shielded in the loom in the engine compartment?

I am going to do a knock sensor by pass after I replace the shielded wire only to test the knock sensor system . If it doesn't throw a code after I replace the shielded wire then I will pull the intake and replace the OEM knock sensor and short wire.

Thank you for any help.

 

Don't go with an aftermarket knock sensor. Only use the Toyota one. Yes, they are pricy. We had to replace ours because it cracked when we took the engine apart. It is buried in there under the plenum.

 

Thank you, I did purchase a OEM Toyota knock sensor and 2 of the short harnesses as well as a 1997 S10 knock sensor for a 2.2.
My plan is to replace the shielded wire all the way from the ECM to the injector harness.. Then to use one of the short harnesses to do a temporary bypass using the s10 knock sensor..
I need to be able to test drive and check a few other things with out having code 52 pop up . I then after a week or so plan removing the plenum and replacing the original knock sensor and short wire.

I had a 2000 GMC Sierra 1500 with the 5.3 that I went cheap on the knock sensors( also under the intake ) and had to do it all over again so I fully under stand what a difference true OEM part vs a cheaper mail order part..

I really appreciate your taking a moment to reach out to me .. Thank you

 

I used the s10 knock sensor bypass , which allows me to drive and diagnose a few other issues with the engine not in limp mode.
I will install the proper OEM knock sensor and short harness soon.

 

Did you get the code 52 figured out and fixed? I am getting the code 52 after I replaced the valve cover gasket on the passenger side of the engine. I may have shifted something or caused a crack in the shielding.
Did you find where that wire goes into the ECU?

 

You gotta remove the plenum AND lower intake. To remove the lower intake you have to take off the No. 2 idler pulley for the timing belt, which is also the water outlet for the intake manifold. The sensor is in the valley of the engine. It’s is a huge pain. So you’ll want to add a timing belt/water pump kit, vacuum lines, and a whole intake gasket set. Since you’ll have that all apart you might as well do the valve covers, PCV valve and hose, rear cam plugs, and cam/crank seals.

 

Code 52 knock sensor is now fixed! The first thing I did was to check the continuity of the black wire (power wire) from the ECU to the pigtail plug. There was continuity so I checked out the physical wire in the harness (had to unwrap it carefully) but only from the knock sensor plug back to where it tracks across behind the power steering pump (passenger side of plenum). I found one crack in the housing and the shielding around that specific area was slightly corroded. I spliced the shielded wire with an aircraft shielded wire all the way to the knock sensor plug. The second pin connector at the KS plug is the grounding component and that pin (brown wire) attaches to the shielding around the black wire fairly close to the KS plug of the main wiring harness.
Next came the labor intensive chore of replacing the knock sensor and the pigtail that plugs onto the KS. Here's where the hard news is.....the Code 52 won't go away if you use an aftermarket sensor. Unfortunatley, the KS is just shy of $300 and the pigtial connector is about $15. Both are available at a local dealership. If you're wanting to DIY this job and want to do it correctly as cheaply as possible, this is the ONLY way to do it. The upper and lower intake manifold gaskets and throttle body gasket also need to be replaced as they're not reusable. I bought OE Toyota gaskets but you can buy an aftermarket kit easily and fairly inexpensive. All the other gaskets can be done with Ultra gray gasket maker.
Other tough news to report is the old addage "a penny for a pound". These cars are now 28 years old! When you take things apart, clips, plastic pieces and wires can be brittle. In my repair, some of the fuel rail mounting bolts plastic spacers broke, needing replacing, as well as the injector seats on the lower manifold that the injectors sit in. Aftermarket parts are easy to find in kits too! I didn't replace the timing belt as mine only had 40k miles on it and was in great shape.
I hope this write up helps encourage someone with the same problem I was having. Post any questions, I am happy to help!