Code 43- Master relay open or grounded

dlivewyer

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I got this code showing and that is what the book shows it is. Where should I look or what do I check?
 

someotherguy

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I got this code showing and that is what the book shows it is. Where should I look or what do I check?
Don't give us too many details, LOL.. like, year, model, engine, any symptoms related, any work done prior to this situation?

What book told you that's what code 43 is? And how did you determine code is 43?

Richard
 

dlivewyer

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Don't give us too many details, LOL.. like, year, model, engine, any symptoms related, any work done prior to this situation?

What book told you that's what code 43 is? And how did you determine code is 43?

Richard
Lol, My bad. '94 2wd 5.7/4l60E. I had a new motor built, 4 bolt main bored .060 over w/flat top pistons and a mild cam. It runs pretty good except the check engine light stays on. I got a "code reader" that essentially only does what a paperclip does and short across the top right 2 holes to make it go into diagnostic mode. It came with a book with all the code meanings. I ran the codes and after the diagnostic flashes, it did 4 flashes....pause....and then 3 flashes. I have since found another source that shows the code 43 as a knock sensor error.

I have another issue also. I believe it has a leaking head gasket. It has a stream of bubbles coming out of the radiator like there is an air line pumping air in to the coolant system. It builds up pressure and pushes coolant into the over-flow bottle and eventually starts to heat up once the coolant level gets low and it's just circulating bubbles through the system. It only takes about 4-5 minutes of idling for it to build enough pressure to start pushing out coolant and the top radiator hose gets rock hard looong before the temperature gauge moves.
 

someotherguy

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OK, yeah as you discovered, 43 is a knock sensor code. Could be bad, disconnected, or the wrong knock sensor for your application.

I'd be far more concerned by that stream of bubbles.. do you see them in the reservoir? You can buy (or borrow) a chemical test kit from the auto parts that should show pretty quickly if it's combustion gases. If you haven't used one, read the instructions closely, but they're pretty easy to use.

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If there's combustion gases in the cooling system the chemical will turn yellow. Do beware though I did get a batch of bad chemical a few years back that wouldn't turn yellow although I was certain a head gasket was blown, and returning it for another bottle got the same result. Got another bottle from a different source and confirmed. Pulled the heads and both gaskets were blown; assume they were just crap quality or not properly torqued.

Richard
 

GoToGuy

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What about warranty with whomever built your engine?
 

Schurkey

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Retorque the head bolts? Pain in the ass as the exhaust manifolds have to come off; but better than ripping the heads off to replace gaskets.

'Course, that air leak into the cooling system could also be a cracked casting.
 

dlivewyer

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What about warranty with whomever built your engine?
After talking with him and hearing him say that he saw the bubbles coming out of the radiator before I picked it up, but yet he let me pick it up anyway and didn't say anything about it, I don't have any confidence in taking it back to him. The motor runs good and sounds strong, even with the issues. I just think I'm gonna take it somewhere else to resolve the head issue. I know it will cost me more money, but I just can't bring myself to take it back to him.
 

dlivewyer

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OK, yeah as you discovered, 43 is a knock sensor code. Could be bad, disconnected, or the wrong knock sensor for your application.

I'd be far more concerned by that stream of bubbles.. do you see them in the reservoir? You can buy (or borrow) a chemical test kit from the auto parts that should show pretty quickly if it's combustion gases. If you haven't used one, read the instructions closely, but they're pretty easy to use.

You must be registered for see images attach


If there's combustion gases in the cooling system the chemical will turn yellow. Do beware though I did get a batch of bad chemical a few years back that wouldn't turn yellow although I was certain a head gasket was blown, and returning it for another bottle got the same result. Got another bottle from a different source and confirmed. Pulled the heads and both gaskets were blown; assume they were just crap quality or not properly torqued.

Richard
I've talked with a very reputable shop about it and I'm gonna take it to them and let them fix it. I just hope it is just crap gaskets or the heads not torqued properly and not a cracked head. I think the knock sensor is not the right one but the shop said they'd fix that too.
 
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