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Used the paperclip jumper method to produce a code 55 - Knock Sensor Failure. Any write ups on how to replace them? I recently moved to an apartment in SoCal so I no longer have tools or a garage Hoping this isn't too involved and I can do it myself.
Any experiences? Is it always the KS's and/or wiring or have some of you had issues with the ecu as well?
My knock sensor issues were resolved by servicing the ECU. Corrosion had just about eaten through the pins to the circuit board for a couple of the inputs.
Did you send the ecu out for service? If so, to who? If you did, did you happen to look at it first to see if you could see the corrosion, in other words, if I open the ECU up, is it possible to see corrosion to help determine if that's the cause?
Hell no! That's like the next worst thing you can do on the SC400 after replacing the starter.
Did you send the ecu out for service? If so, to who? If you did, did you happen to look at it first to see if you could see the corrosion, in other words, if I open the ECU up, is it possible to see corrosion to help determine if that's the cause?
I had a local circuit board tech do the work, having already ordered the proper capacitors. I did look it over first and couldn't see the damage, but once he removed the caps it was very evident.
The corrosion of the input pins/traces was nearly impossible to see because it's under the thick metal bridge where the harness connects. It was only evident when he had de-soldered all the pins to pull it apart.
As the other poster says, you may have an ECU problem. But, given the crappy insulation on the wiring for these models, you could have a wiring issue. Just note the KS wiring is shielded wire up to within about 3 to 5 inches of the sensor and the shielding grounds to the engine ground EC according to the wiring diagram.
Or, you could have a bad sensor, that's what I had. I ordered a new one, replaced it and still threw the code so I assumed it was the wiring or the ECU. I swapped the ECU from my other car and it threw the code so I ran new wire and it still threw the code. Ordered another sensor and problem solved. Here is a link to my build thread where there is a little more info if you need it.
Does anyone happen to have a step by step on how to replace the knock sensors or where they're located? I found a thread for a MKIII supra, is this correct? It is showing there is only one for the NA version of that motor.
Would I need to drop the alternator to get to the KS's?
Is this a 2JZ or 1UZ? If 2JZ, its simple, no need to remove anything but the plug. It is behind the power steering pump if its the front one, the rear one is a little harder to get to. The fault code will tell you which one. But unplug the sensor wire, use a socket that I think is a 24mm but not sure, unscrew it from the block. Screw the new one in, tighten it, plug the wire back on it and done.
The trick is going to be not breaking the plug. They get brittle and most likely will break unless you really really treat it like your grandmother's china. Then it may break anyway. If it does, order the new plug from Driftmotion or Dr ________ (somebody help me here can't remember the name).
Don't over complicate it, the hardest part is unplugging and plugging back up without breaking the plug. Simple job.
Good luck
Originally Posted by beenlookin
Awesome build.
Does anyone happen to have a step by step on how to replace the knock sensors or where they're located? I found a thread for a MKIII supra, is this correct? It is showing there is only one for the NA version of that motor.
Would I need to drop the alternator to get to the KS's?
Is this a 2JZ or 1UZ? If 2JZ, its simple, no need to remove anything but the plug. It is behind the power steering pump if its the front one, the rear one is a little harder to get to. The fault code will tell you which one. But unplug the sensor wire, use a socket that I think is a 24mm but not sure, unscrew it from the block. Screw the new one in, tighten it, plug the wire back on it and done.
The trick is going to be not breaking the plug. They get brittle and most likely will break unless you really really treat it like your grandmother's china. Then it may break anyway. If it does, order the new plug from Driftmotion or Dr ________ (somebody help me here can't remember the name).
Don't over complicate it, the hardest part is unplugging and plugging back up without breaking the plug. Simple job.
Good luck
Sounds good, its a stock 2jz motor. The code it throws is 55, from what i read its number 2, any idea if its the rear? Thanks for the info, i'll have time to check it out this weekend.
Sounds good, its a stock 2jz motor. The code it throws is 55, from what i read its number 2, any idea if its the rear? Thanks for the info, i'll have time to check it out this weekend.
Going to put what I sent you in the pm for future reference.
This shows generally where the sensor is. It's screwed into the block with a single wire connector connected to it. It isn't easy to see, it's under the intake manifold.
This is what you are looking for. It's just above the starter, its the sensor with the single plug in the center of this picture. Be very careful unplugging the plug from the sensor, it is probably brittle and may break if you get too rough with it. If you break it, try to get it to stay plugged with a tie wrap or worst case order the new plug from Driftmotion. It's a beyotch to get the wire unplugged from the old plug and into the new one so hopefully you won't end up having to do that like I did.
Knock sensor #2 screwed into the block just above the starter with the single wire connector plugged into it.
My SC300 has the same code as the thread starter (Code 55).
For those of you that have replaced their rear knock signal sensor, did you remove the intake manifold or starter to access the knock sensor? Or were you guys able to reach for it and access it blindly?
Starter needs to be pulled - that's it. I should also mention that the new knock sensor did not fix the issue. PCM is next unless anyone can suggest anything different.
I've replaced the REAR knock sensor as indicated by code 55 with an OEM Denso unit but no luck getting rid of the engine code/light. All wiring and the clamp to the knock sensor is good. I've disconnected the battery
and the light remains on. Is there something else I should look at? Is the light simply burned into the ECU or is this another problem?
04-10-16, 09:43 PM
1992 SC300 Check Engine Light Throwing Code 55 - Knock Sensors Tutorials? Write Ups?
Hoping this isn't too involved and I can do it myself.
That's like the next worst thing you can do on the SC400 after replacing the starter.
