Code 43 Knock sensor questions
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Intermediate
Joined: Mar 2002
Posts: 33
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From: North Huntingdon pa
Code 43 Knock sensor questions
I dumped the codes today and got the reason for my SES light. I had 2 code 43s. That's about right. I have had the car 4 months and twice got a SES light for a second or two when I was cruising at highway speeds for more than 20 minutes or so at low RPM. The car runs fine.
I read the archives and it says to Check ECM wiring and/or replace knock sensor. Archive posts also say to check the wiring on the sensor too. How exactly do I check the ECM wiring, just make sure it is plugged in? How about checking the knock guage wiring? Do the same? Just make sure it has a good connection by giving it a twist?
Are there two of them? I understand that the knock sensor is on the bottom of the engine, somewhere around the oil filter on one side and ? on the other. Are they easily recognizable?
Should I be worried about this since it is so intermittent?
Thanks!
I read the archives and it says to Check ECM wiring and/or replace knock sensor. Archive posts also say to check the wiring on the sensor too. How exactly do I check the ECM wiring, just make sure it is plugged in? How about checking the knock guage wiring? Do the same? Just make sure it has a good connection by giving it a twist?
Are there two of them? I understand that the knock sensor is on the bottom of the engine, somewhere around the oil filter on one side and ? on the other. Are they easily recognizable?
Should I be worried about this since it is so intermittent?
Thanks!
Advanced
Joined: Apr 2001
Posts: 88
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From: oakdale,mn,u.s.a.
Re: Code 43 Knock sensor questions (webmstrjay)
Make sure the knock sensor(s) is torqued correctly. I test to make sure that it works by taping ( a good hard tap) on the block next to the sensor. The idle should go up and down for a second (timing should change). Or try unpluging the sensor while it is running? If you don't run high octane, try that? I am no pro though. hope this helps.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Code 43 Knock sensor questions (webmstrjay)
The ECM periodically tests the knock sensor by advancing the timing till (within limits) a knock is detected. When that fails the code is set.
Burning Brakes
Joined: Aug 2000
Posts: 984
Likes: 1
From: Cincinnati OH
Re: Code 43 Knock sensor questions (webmstrjay)
I recently had this problem, posted the procedure for a '92 in another thread:
Ignition on, disconnect the knock sensor connectors and measure voltage b/w the knock sensor connectors and ground, should be 5v. (if not, check wiring, then ecm)
If that's ok, measure the resistance b/w the knock sensor terminal and ground, should be 3300-4500 ohms. (if not, most likely the sensor is bad, about $30 at any parts place)
In my case, the code 43 was intermittent, but finally one of the knock sensors gave up completely. When measuring the resistance, one was open, dead giveaway.
Also, make sure the sensors are torqued to spec, this is important. It's possible someone changed the coolant and didn't torque it properly. Also, do NOT use additional sealer or teflon tape on the threads.
Hope this helps.
Ignition on, disconnect the knock sensor connectors and measure voltage b/w the knock sensor connectors and ground, should be 5v. (if not, check wiring, then ecm)
If that's ok, measure the resistance b/w the knock sensor terminal and ground, should be 3300-4500 ohms. (if not, most likely the sensor is bad, about $30 at any parts place)
In my case, the code 43 was intermittent, but finally one of the knock sensors gave up completely. When measuring the resistance, one was open, dead giveaway.
Also, make sure the sensors are torqued to spec, this is important. It's possible someone changed the coolant and didn't torque it properly. Also, do NOT use additional sealer or teflon tape on the threads.
Hope this helps.
