Knock Sensor CEL Woes, Running like crap

[acai]

Simply disconnect the knock sensor wires and go for a drive. I'm curious what would happen. Also, what is code 55 in OBD-1?

I drove with a knock sensor #1, #2 code for months w/o any issues. That's when I discovered the actual sensor wire was bad between the sensor and the ECU so I replaced both of them. Admittedly, I have OBD-II so perhaps the ECU is programmed differently, I dunno.

@alia176 What entails replacing the entire wire? Code 55 is a rear knock sensor error.

Thanks

 

[landtank]

If the ECU doesn't see a sensor plugged in or the reading from the sensor is not within specs the ECU will pull timing out in large amounts.

This is the go to routine when the ECU wants to protect the motor. Retard timing and dump fuel.

I've had a bunch of these sensors fail in the last couple of years. Fist thing I do is replace both of them and then move onto wiring if the code persists.

 

[Tedward]

@landtank
Thanks for knowing and posting.

Keeps me from doing a head gasket when I get home!

 

[alia176]

@alia176 What entails replacing the entire wire? Code 55 is a rear knock sensor error.

Thanks

It wasn't too bad just kind of tedious. I didn't want to trace the sensor wires through the wire loom and all that jazz so basically snipped off the two sensor wires at the ECU, then ran two new wires to the sensors. These are single, stranded wires so pretty easy to snake through the engine bay as needed.

Our rigs are getting long in the tooth and the wiring harness is degrading as they normally do. If I had the funds and the energy, I'd just replace the entire harness and be done with it. Lots of little things will happen as the connectors and wires get older and suffer through countless heating/cooling cycles.

 

[acai]

New OEM sensor seems to have solved the problem for me ! Onto the next thing ...

 

[alia176]

That's awesome news, congrats!!!

 

[CleryCruiser]

Where are you in CA? I have 4 extra, known to be good, Knock sensors. You could slave one in if you live close enough.

I know it’s a long shot but do you have any of those Toyota knock sensors available? I’m throwing code 55 and I replaced with a cheap autozone sensor with no luck. I don’t want to spend $160 on a knock sensor bc I’m doing an LS Swap in early 2021 but I would like my engine to run properly until then. Please let me know if you would be willing to sell and ship to the Chicago area? Thanks!

steve