I replaced the knock sensor, esc module, and all wires look ok. I unpluged the knock sensor which made no changes, the code still pops up? code 43 only occurs under load. Engine running in neutral revs to the sky with no problems or codes. I do have fresh gas, 92 octane, as well. Any ideas on what else to look for would be great. TIA


[Modified by vettemech85, 5:43 PM 4/12/2002]

 

There has been a lot of great information posted on this subject that I did a search on and read. I’m not sure if you know, but if you go to the top menu, there is a search option and use the C4 section and try code 43 or knock sensor as the description and you should find a lot of help on this subject.

:cheers:

 

The code arises when the knock sensor fails to respond to the regular test by the ECM. Look into wiring connections or a failed sensor (proper torque on installation).

If you have access to a scan tool, rap firmly (carefully where) on the block and see if you get "knocks". Even without a scanner I believe you should hear the idle change if the sensor is functioning properly.

 

Heres how I got mine fixed...thanks to David F on the forum for the advice.After I had my motor rebuilt and put everything back in the car,I got a code 43.It turns out that my knock sensor wasnt grounding to the engine block because for one,I put some silicone sealer on it which I should not have and 2,they repainted the block with new black paint during the rebuild so I had to sand the hole in the block to make a good ground.
Cleaning the silcone off and cleaning the block to shiny metal helped.

It also turned out that my knock sensor wasnt hearing knock at the factory torque setting.So I kept turning the sensor until it was just about all the way screwed in,THEN it started to pass the 43 test.What the ecm was doing,when under load,it performs a self test to determine if it can hear the knock.It deliberately advances the timing for a few seconds and when the motor pings,the sensor tells the ecm its hearing it,and its working so the test is passed and normal driving remains.

If it fails the test,it will go into a mode to prevent you from damaging the engine and run at a fixed timing,which is unbearable to drive.Its like a safety measure in case your engine was in fact pinging like marble can but couldnt tell the ecm what was happening.

Because I have a Snap On scanner,I was able to stand outside the motor with it running and watch the knock counts.I took a hammer and tapped the exhaust manifold and seen there was no knock recorded.After I cleaned the silicone off,cleaned the block hole,and screwed the sensor in more,with the hammer test to the exhaust manifold,it started recording the knock noise and i knew I had it fixed.

After that,wasnt a problem again.Sorry If I rambled and maybe you know most of this but this is also to help others who may have had these problems and made the same mistakes but doesnt know much about it.If you have a scanner,its much easier to see if the knocks are being heard.

If everythings good,but still have a problem,you may need to check the voltage at the wires and trace it back to the ecm and see if theres a voltage drop or if the ecm itself cant read the voltage signal there.The shop manual can guide you through it if thats the case.
Good Luck.
:)

 

That's a great post Bill :cheers:

Stupid me Teflon taped mine. I was getting the 43 and climbed under the car and checked the resistance to ground and it checked okay. I then checked the voltage coming in and that checked okay. I put everything together and the 43 dissapeared. Maybe I just had a poor connection. When it comes back, the Teflon is coming off.

 

I will go out and try the block tap test again, it worked last fall I think? Should the wire at the sensor show a voltage reading? Or is it a negative wire? Thanks again for all the great responses :cheers:

 

On my 92, with the ignition on, you are supposed to get around 5v going into the sensor. It is not a gound. :cheers:

 

One more thing, you are supposed to disconnect both of them first, turn on ignition, then check the voltage to each one. Each is supposed to be around 5v coming in from the ECM.

 

No power at knock sensor with the ESC pluged in and ignition on, wire is good though.Battery voltage present at ESC harness on terminal B, ignition power as far as I can tell. Black ground wire, d ,works. Would that indicate that the ESC fried again? TIA


[Modified by vettemech85, 8:30 PM 4/12/2002]