I have an '02 silverado with the 4.8l engine and I am getting a P0332
code "knock sensor signal frequency outside normal range". I have
cleared it several times but it comes back withing a few minutes. Does
this mean the sensor is bad or is it telling me the engine is
knocking? The sensor is under the intake manifold so it is a faily big
job to replace it. What else should I look at? Thanks for any help.
It tends to suggest it is bad. GM in their wisdom moved it from a
easily accessable location that was externally mounted with a SB
series motors to the internally mounted one used with the new modular
motors (4.8, 5.3 and 6.0)
The theory behind this supposidly in that in the valve lifter galley
it is closer to the heads and can "hear" better but if that it where
they wanted to put it they could have compromised with a design that
did not require you to remove the intake to change the sensor.
There are actually two sensors. It's not as bad to get at as you
might think. And if they are more accurate in that location, you
have to weigh the pro's against the con's. I know that in the
8 years that this design of engine has been out, we haven't replaced
very many knock sensors on these engines.
There were some issues with leaking intake manifold gaskets on
these engines (not coolant, as they are not a wet manifold, but
a vacuum leak). So if you are going to have the intake manifold
off anyway, you could install the updated manifold gaskets.
Here is the updated gasket number from the GM bulletin.
"Replace the upper intake manifold gaskets with the teal green gasket
material, P/N 89017589."
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