I have a service engine soon light caused by code 43, knock sensor circuit, this is also causing my car to continually run in open loop mode.

The mechanic that scanned the car, said its either the wire b/w the computer and the knock sensor or the knock sensor itself.

I checked the ohm's on the wire b/w where the connector is and up under the hood. It was reading around .6 or .7 I used the end where it hooks up to the connector and up top by the computer i used a needle to stick into the wire.

Therefore i think its the knock sensor that needs to be replaced. BUT i have the knock sensor completely zeroed out on the pcm tables. I'm not using the knock sensor.

Do you think its simply the computer picking up that i'm not using the knock sensor and therefore thinking its broken and causing the "code 43 knock sensor circuit" light to be on?

I don't think replacing the knock sensor will do anything since its not being used at all...

Anybody know what the resistance on that wire should be?

 

bump

 

have you tried re-enabling the knock sensor in the pcm and seeing if the code goes away?

 

yes, i'm planning on doing that... But i'm wondering if the code will come back after the knock sensor is zeroed out again?

 

OBD-I KS test

With the connector off the KS, check for 5v on the harness terminal with key ON. Continue if that is good.

Key OFF. Connector off. Measure the resistance between the KS terminal and ground. Resistance should be between 3300-4500 ohms. If it is not, the sensor is faulty or the sensor is not making good contact with the block.

If all that is good, it might be the knock module or faulty pcm.

 

By "zeroing it out in the programming" I assume you have just eliminated the PCM's response to knock. But the PCM is still looking for the KS circuit to be intact. Unless you somehow found a way to attempt to disable the diagnostic, rather than just eliminate any PCM response. It needs a good wire and a good sensor in the circuit, or you get the code.

You also indicate that this is causing you to continually run in open loop? Odd... all I have ever seen it do is default to some very high, and variable knock retard.

 

Mine used to do the same thing but only when I would get on it. I had a brand new KS and every stuff. I was getting a lot of false knock anyway's even on race gas so I just bypassed that thing all together. All you have to do is go into tunercat and UNCHECK the KNOCK SENSOR DIAG 43 in the ECM SWITCH table. Then I go into all the RETARD TABLES and ZERO them out. Of course make sure you don't really have any knock before you do this

 

not sure if i got this right, but i'll describe everything step by step.

key on, red wire to the ks connector, black wire to ground, set on volts dc got 4.78 reading.

key off, red wire to the ks connector again, black wire to ground, set on ohms, got 4.05

does this mean my sensor is faulty since i get less ohms'?

 

all we did on the pcm tables was set the max retard for zero degrees. i belive i'm in the open loop mode based on the fact that the computer is not using the o2 sensors ...at idle they are both around 70 or 80mv instaed of jumping around 400-900 when you rev up, also my gas milage went from about 16mph to 11mpg

 

You misunderstood the second test. The second test is to test the KS, since the first part checks the harness.

Put one lead on the KS terminal (not harness) and one lead to ground and read resistance.

 

plugged red wire into the knock sensor itself and black wire to a ground and the multi-meter wasn't reading anything at all. I tried several different grounds but still, no readings at all.

 

If you cannot get a resistance reading between the terminal on the KS and ground or the metal body of the sensor, the sensor is open.

 

what does that mean? the sensor being open part?

 

ttt

 

Make sure the KS isn't 'insulated' from grounding in the block [for example, by too much teflon tape/sealer etc.]
It has to have a good ground from it's body to the engine block..
Try the ohmmeter from the KS terminal to the body of the sensor and see what you get..