Code 43 knock sensor fault.

[hclanton93]

I have a 95 k1500 with the 5.7. I’m getting a code 43(Knock sensor fault) with in 10 seconds of start up. The timing is set to zero. I have replace the knock sensor and harness. I have also replaced the temp sensor and the ECM I continue to get the code 43. The truck is sluggish the motor was replaced 3 years ago.

 

[Schurkey]

95 k1500 with the 5.7.

getting a code 43(Knock sensor fault) with in 10 seconds of start up. The timing is set to zero.

Have you connected a scan tool to verify the knock sensor output? Do you hear knocking of any sort--detonation, lifter noise, rod knock, cracked flexplate, etc.?

I have replace the knock sensor and harness.

The ENTIRE harness, or just the connector and a few inches of wire (pigtail)?

I have also replaced the temp sensor

Why?

and the ECM

Why?

I continue to get the code 43. The truck is sluggish the motor was replaced 3 years ago.

Download the service manual set for your vehicle. Follow the diagnostic procedure for Code 43.

 

[1997]

43

Knock sensor (KS)

Wiring open circuit/short circuit to ground/short to positive, KS, PROM, ECM

PROM, maybe you need to double check installation if you replaced ECM.

 

[hclanton93]

Have you connected a scan tool to verify the knock sensor output? Do you hear knocking of any sort--detonation, lifter noise, rod knock, cracked flexplate, etc.?

I don’t have a obd1 scanner. I don’t hear any noises.

The ENTIRE harness, or just the connector and a few inches of wire (pigtail)?

I replaced the pigtail

I replaced the temp sensor because I saw where it could cause the issue.

I replaced the ecm because I read where it might not be advancing the timing to test the knock sensor

 

[hclanton93]

I also have a Haynes manual and it doesn't help with the code 43

 

[PlayingWithTBI]

I also have a Haynes manual and it doesn't help with the code 43

Throw the Haynes manual away and download a proper Factory Service Manual for your truck
www.gmt400.com/threads/88-98-service-manuals.43575/

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[hclanton93]

I just wanted to make an update, For anyone else who may have the same problem and comes across this post. The truck had the wrong knock sensor in it when I got it and when I replaced it I replaced it with the same one. It had a white connector on the sensor the correct one for this truck is the black one. It is no longer throwing a code 43.