1998 ES300 Knock Sensor Replacement
02-10-11, 06:02 PM
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1998 ES300 Knock Sensor Replacement
I am kind of a beginner working on cars. I have worked on older trucks and tractors so I do know how to use a wrench. I got this car about a year ago and I changed the timing belt, alternator, battery, windshield wiper motor, window motors and have updated a lot of things in the car. So now onto knock sensors, I have read other posts saying not to do the knock sensor yourself because it is a very hard process, and others say just take off the manifold and a few hoses and your right where you need to be. I am hoping someone with experience of doing this themselves could give me some insight. In the end I will have to do this myself since i'm a broke college student trying to make this car last me til i get my mastors. So if anyone could help me I would really appreciate it.
02-10-11, 06:54 PM
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If you have allready replaced your timming belt, you should have no problem with the knock sensors. Is one, or both of them bad? If only one is bad, you could wire both inputs to the good sensor. Having two knock sensors, especially since they are physically so close, is rather redundant.
02-11-11, 08:14 PM
#4
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You can double check to see if they are defective by testing them as follows:
Using an ohmmeter, check that there is no continuity between the terminal of each knock sensor and its body. The ohmmeter reading should indicate an open circuit. If there is continuity, replace the knock sensor.
Using an ohmmeter, check that there is no continuity between the terminal of each knock sensor and its body. The ohmmeter reading should indicate an open circuit. If there is continuity, replace the knock sensor.
02-13-11, 03:18 PM
#5
I recently had my knock sensors replaced by my local Lexus dealer. I was getting a check engine light, scanned it and came back as a defective knock sensor. In doing my search on here, I read that if your going to replace one, you might as well replace the other and also, a very good idea is to replace the sub-harness wiring. The reason to replace both knock sensors, because of the location of the knock sensors and the time involved to get to them. The reason for replacing the subharness is the same reason, location and time to get to them, also, the heat of the engine and where the wiring resides on the engine, causes the wiring to become brittle and eventually the wires become exposed and start shorting.
02-13-11, 03:48 PM
#6
I recently had my knock sensors replaced by my local Lexus dealer. I was getting a check engine light, scanned it and came back as a defective knock sensor. In doing my search on here, I read that if your going to replace one, you might as well replace the other and also, a very good idea is to replace the sub-harness wiring. The reason to replace both knock sensors, because of the location of the knock sensors and the time involved to get to them. The reason for replacing the subharness is the same reason, location and time to get to them, also, the heat of the engine and where the wiring resides on the engine, causes the wiring to become brittle and eventually the wires become exposed and start shorting.
02-13-11, 09:27 PM
#7
I have a female friend that works at my local Lexus dealer that works in the service dept. She's the one that writes up the service ticket, not a mechanic. Anyways, she gave me a deal and I had it done for about $850 dollars. One knock sensor runs about $300 dollars or so and the sub-harness is like $30 dollars, then factor in labor, which is about $110.00 an hour. I think the job is about a 2 or 3 hour job. She gave me a good deal on the service.
Last edited by angmedic91; 02-22-11 at 05:07 PM.
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02-22-11, 10:22 AM
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Thanks for everyone's input on my little problem. I haven't changed it yet, but i finally get paid this week so I am looking forward to the good weather, 2 knock sensors and the harness. Is there anywhere online I could find a diagram to get this done any faster? PFB thanks for the ohmeter idea, I wouldn't have thought about it. I don't think I can fork out 850, that would cut into my home brewing equipment. I need to get a new fridge for 3 kegs sitting in my garage waiting to get cold. Thanks for everyone's help.
03-18-11, 08:58 AM
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Since a knock sensor with no continuity is good can I just cut or disconnect the wires to the knock sensors, use premium gas and live without both them? Both my sensors are bad on my 96 ES 300 and I just want to get the engine lite off so I can get my car inspected. It this will work where is the easiest place to cut the wires?
03-18-11, 07:34 PM
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No. The sensors are pizo electric crystals that generate a voltage when exposed to vibration. The ECM expects to see some vibration, even when the engine is running normally. If you disconnect the sensors, you will still have a code.
