Code 43

TRAVIS1989

MEMBER
1989 CHEVROLET SILVERADO
5.7L
V8
4WD
AUTOMATIC
115,000 MILES

Truck runs fine until it gets warm and then code 43 comes up and truck has no power at all and barely wants to stay running. I've had this problem before and don't remember what I did to fix it. Where do I start with this problem?

Tuesday, June 22nd, 2021 AT 2:28 PM

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

This is a knock sensor code so here are a few guides that will help with getting us started:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

https://www.2carpros.com/articles/how-a-knock-sensor-works

Below you will find the testing from the manual that we need to run through to figure out what the possible cause is of this.

Please let us know what questions you have. Thanks

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Wednesday, June 23rd, 2021 AT 6:06 PM

TRAVIS1989

MEMBER
16 POSTS

In the diagram to check the ESC module, when it says "scan" what exactly does that mean?

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Thursday, June 24th, 2021 AT 5:46 PM

KASEKENNY

MECHANIC
18,907 POSTS

This means the scan tool is be set on the knock sensor info to monitor voltage. Basically it just wants you to see if the sensor is sending a signal that the PCM is seeing.

If you don't have this, I would just test it both ways and that will tell you which it is. So start with assume that it does so you answer it yes and move to the next step. Then run through that test until you get to a failed part. Then do the same thing with answering no and see what it leads to.

Let me know if you have questions on this. Thanks

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Friday, June 25th, 2021 AT 7:36 PM