I have gotten a code 43 a few times in the last month and i cant figure out what it is. I found (1) source of info that says its the knock sensor-low/high voltage but that is all i have found. Im using Tunrepro rt and dont see anything wrong with the knock sensor as far as retard, knock counts, and etc. Anyone know anything about code 43?

 

check the connector on the knock sensor, over time the plastic starts to break down & causes it to become loose & cause a poor connection. while your under there check the knock sensor wire for insulation flaking off & shorting to any thing.
the sensor it self could also be starting to go bad.

 

Okay, here`s the deal....code 43 defines as ESC control problem but the faliure is usually the knock sensor like you have been finding out.
Here`s how to go about checking it, check the condition of the wiring and connector as DENN_SHAH stated.
with the key in the on position and sensor unplugged, probe the pigtail with a DVOM and check for the 5 volt refrence signal coming from the PCM, if you have 5 volts there all is good to the sensor
Now with the sensor plugged in, back probe the wire, the knock sensor should have pulled down the voltage to 2.5 volts, if it does not replace the knock sensor

 

Alright. Thanks guys for your help.

The thing that had me puzzled is that when i have tunerpro running and im datalogging the knock sensor it picking up knock counts and he esc is retarding the knock per the sensor. Im out in the boone sticks now and im stuck on dial up but ill do what yall said and get back to you as soon as i get home to me broadband. Man you can live without the high speed. I feel sorry for the poor dail up guys.

Brian

 

sorry to bring up back a some-what old topic...I'm havin the code 43 problem as well. I checked the voltage goin to the knock sensor and its readin 4.8 unplugged and 2.2 plugged in..so I'm thinkin its not the knock sensor because the voltage is so close to what it should be. If infact its not the knock sensor, what do i need to be looking at next??

thanks

 

btw, i just noticed this is in the TPI section, and my car is TBI...i dont know if that maked any difference.

 

The sensor should pull the voltage down to 2.5...it`s possible though that the ecm is not seeing that, might want to check the pin at the ecm for that voltage.

 

Your TBI system and the '90-'92 (SD) systems are different. The test for 2.5 volts at the sensor is not valid for the TBI setup.

A code 43 on the TBI setup is caused by one of two tests that the ECM runs. If the knock counter is just running away (endless knocks reported), that will set a code 43.

The other test is the more prevalent to setting code 43. In this test, when in PE mode (WOT) the ECM adds a bunch of timing to force the engine to knock. If the knock system reports knock, all is good and the test is not run again until after a key off.

If knock isn't detected the test is run a second time. If this test also fails then code 43 is set and the SES lights up. Engine power is reduced as a set amount of timing is also pulled. This lasts until after a key off.

Al.

 

well i thought i had it fixed..replaced the knock sen. even tho the voltage was ok. today on the highway i went to pass someone and my ses light came on and i had no throttle responce at all. About 2 minutes away from home I noticed a burning smell..couldn't pin point it to a location..wasnt under the hood tho.. anyway...

Since I replaced the knock sen. and that didn't fix it, what needs to be replaced now? I'm still not sure..