2002 5.7L Vortec P0327 diagnosing help 0411 - Pinout?

[eXo0us]

Hello,

my Chevy Express RV is starting to throw a P0327 code.
First I started the parts canon, - new pigtail and new AC-Delco sensor. No change - potentially even more frequently....
Then I found here in Forum the Manuals. - thanks for this.

I'm following the troubleshooting Guide DTC P0327 Knock Sensor Noise Channel Low Voltage.

Step 1: DTC is set - YES
Step 2: Failed this Ignition: Yes - got to Step 4
Step 4: 100K Ohm. - yes
Step 5: I don't have something to measure frequency
Step 6: Knock sensor has 0 Ohm to Alternator Ground.
Unplugged PCM harness from PCM - checked KS-Pigtail - indefinite Ohm- so I do not have a ground short.
Step 7: Ignition ON - Knock Sensor connector 0.4V - should have 5V reference ?? This is a single wire sensor
Ignition Off 0.0V on knock sensor connector.

I've check my pigtail connection and I have the same voltage before the pigtail repair. So it seems like I'm loosing voltage somewhere.

Next the guide says - remove VCM C2 connector and check connectivity. I got a 0411 PCM from Workhorse in the RV.
There a bunch of dark blue wires in the C2 connector.

Which one is the Knock sensor?

 

[eXo0us]

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Looks like the guide is not a perfect match for 0411 Express PCM - the KS- is on the C1 Connector and not on C2.

Does the 0411 even send out 5V reference? or is the BlackVCM which sends 5V?

 

[L31MaxExpress]

It is very possible the infor you are looking at was for a black box truck. Quick glance shows the knock sensor on C2-19 on a blackbox. C1-51 is correct for an 0411 or P59.

From memory with the knock senaor disconnected there is a 5V bias voltage. With the knock sensor connected it is under 1V bias. If the wrong knock sensor or a faulty one is connected the voltage will drop under the specified voltage and give you the P0327. The knock sensor creates an AC voltage that catches a piggy back ride on the DC Bias voltage as part of the noise filtering of the signal.

 

[eXo0us]

at was for a black box truck. Quick glance shows the knock sensor on C2-19 on a blackbox. C1-51 is correct for an 0411 or P59.

From memory with the knock senaor disconnected there is a 5V bias voltage. With the knock sensor connected it is under 1V bias. If the wrong knock sensor or a faulty one is connected the voltage will drop under the specified voltage and give you the P0327. The knock sensor creates an AC voltage that catches a piggy back ride on the DC Bias voltage as part of the noise filtering of the sign

thanks,

yeah, I don't have 5V when sensor disconnected and ignition on. Should the engine running to get 5V?
Any fuses which supply the PCM with power to create the 5v?

The KS-sensor wire is not grounded and I checked it complete to the PCM.

Any other components which could be pulling the 5V reference to ground so it's not arriving at the Knock sensor anymore?