DTC P0327 & P0332 - what is actually tested - how to dial out false knock/valvetrain?

[Tongboy]

Immediately after a cam swap i'm now getting both codes as fast as I can get them (2nd drive cycle immediately)

i've scoured the internet, read hotrodlane - http://www.hotrodlane.cc/New%20LS%20...or%20P0332.htm and everything else I can find and I can't find the actual details of what specifically the low voltage codes mean aside from what the name implies.

I believe what the sensors are seeing is the newly introduced valvetrain noise with the new cam & valvetrain, I can't hear any knock, the knock sensors still seem to detect and deal with occasional burst knock while driving around. no mechanical faults are apparent.

Can the knock table be used to adjust for this? does increasing or decreasing the multiplier increase or decrease the sensitivity of the sensors? I understand by changing the cam the manifold pressure & load is different than it was stock.

drivetrain is an 01 fbody pullout wired into a 97 bmw 3 series. I put ~7k miles on the "new" knock sensors with no issues until the cam swap - went to 243 heads and a 226/230 EPS cam - ls7 lifters & 7.425 pushrods.

any help or insight is much appreciated.

[mecanicman]

DTC P0327 or P0332
Circuit Description
The knock sensors (KS) produce an AC signal during all engine operating conditions. The powertrain control module (PCM) calculates the average voltage range of each KS signal. If the KS system is operating normally, the PCM should monitor the KS voltage varying above and below calculated average voltage. If the PCM detects a KS 1 signal or a KS 2 signal voltage within the calculated average voltage range, a DTC will be set. DTC P0327 refers to the front knock sensor. DTC P0332 refers to the rear knock sensor.

Conditions for Running the DTC
DTCs P0117, P0118, P0121, P0122, P0123, P0125, P1114, P1115, P1121, and P1122 are not set.
The engine speed is between 1,650-3,000 RPM.
The MAP is less than 49 kPa.
The engine coolant temperature (ECT) is more than 60°C (140°F).
The throttle angle is more than 0 percent.
The engine run time is more than 10 seconds.
Ignition voltage is more than 10 volts.
Conditions for Setting the DTC
The PCM determines that this frequency is less than the expected amount for more than 9 seconds.

Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Check the knock sensor for proper installation. A knock sensor that is loose or over torqued may cause the DTC to set.

If DTCs P0327 and P0332 are set at the same time, inspect for poor connections at the KS harness jumper, located at the rear of the intake manifold.

For an intermittent, refer to Intermittent Conditions .

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step verifies that the malfunction is present.

Tapping on the engine block will simulate an engine knock.

Step
Action
Values
Yes
No

Schematic Reference: Engine Controls Schematics

1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls

2

Important
If you can hear an engine knock, repair the engine mechanical condition before proceeding with this diagnostic. Refer to:


Engine Noise on Start-Up, but Only Lasting a Few Seconds in Engine Mechanical-5.7L
Upper Engine Noise, Regardless of Engine Speed in Engine Mechanical-5.7L
Lower Engine Noise, Regardless of Engine Speed in Engine Mechanical-5.7L
Engine Noise Under Load in Engine Mechanical-5.7L
Review the Freeze Frame/Failure Records data for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC . Attempt to duplicate the Freeze Frame/Failure Records that you observed.
Does the scan tool indicate that this diagnostic failed this ignition?
--
Go to Step 3
Go to Diagnostic Aids

3
Disconnect the knock sensor electrical connector, located on the left side of the intake manifold.
Set the DMM to the 400 K-ohm scale.
Measure the resistance of the appropriate knock sensor using the DMM connected to battery ground.
Is the resistance of the knock sensor within the specified range?
93-107 Kohms
Go to Step 4
Go to Step 6

4
Connect the DMM between the appropriate knock sensor signal circuit on the sensor side and the engine block.
Set the DMM to the 400 mV AC hertz scale. Refer to Measuring Frequency in Wiring Systems.

Important
Do not tap on the plastic engine components.


Tap on the engine near the appropriate knock sensor while observing the signal indicated on the DMM.
When you tap on the engine near the appropriate knock sensor, does the DMM indicate any signal?
--
Go to Step 5
Go to Step 7

5
Disconnect the PCM connector. Refer to Powertrain Control Module (PCM) Replacement .
Test the KS signal circuit between the PCM and the knock sensor connector for the following:
An open
A short to voltage
A short to ground
Did you find and correct the condition?
--
Go to Step 12
Go to Step 9

6
Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical-5.7L.
Test for an open or a short to ground in the signal circuit between the knock sensor jumper harness connector, located at the rear of the intake manifold, and the knock sensor connector. Refer to Testing for Continuity and Testing for Short to Ground in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 12
Go to Step 7

7
Inspect the KS signal at the appropriate knock sensor. Refer to Testing for Intermittent and Poor Connections .
If you find a poor connection, repair the connector as necessary. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 12
Go to Step 8

8
Replace the KS. Refer to Knock Sensor (KS) Replacement .

Did you complete the replacement?
--
Go to Step 12
--

9
Inspect the KS signal circuit for a poor connection at the KS jumper harness connector. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
If you find a poor connection, repair the connector as necessary. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 12
Go to Step 10

10
Inspect the KS signal circuit for a poor connection at the PCM. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
If you find a poor connection, repair the connector as necessary. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 12
Go to Step 11

11
Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .

Did you complete the replacement?
--
Go to Step 12
--

12
Use the scan tool in order to clear the DTCs.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run and pass?
--
Go to Step 13
Go to Step 2

13
With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?
--
Diagnostic Trouble Code (DTC) List
System OK

[Tongboy]

oops, good call, used to having a signature on forums but i'm new around here.

motor is out of an 01 fbody running the fbody management & wiring

Thank you though - that is better info than i've been able to find anywhere else.

any further info available with the engine detail info?

[mecanicman]

I changed the above information to a 2001 fbody, but it is almost the same.

[69lt1bird]

For future reference, this site is great for DTC information.

http://gearchatter.com/