Jake T

I just replaced both knock sensors and the harness. Took the car for a short ride and got a 327 and a 332 both are knock sensor codes. Anyone have any ideas?
Jake

Kmcoldcars

Just because you have knock sensor codes does not mean the knock sensors are bad. The code means something in the knock sensor circuit is not working right. You need to get your factory service manuals out and do the troubleshooting sequence in them to find the problem. Or keep spending money for parts that are not needed and maybe get lucky and fix the problem.

Jake T

Makes total sense. That's what I'm going to do. I'll have to purchase a factory service manual. Can't understand how two knock sensors can be bad at the same time. Especially when I just installed them, including a new harness. I was meticulous doing the install. Checked and rechecked everything. Initially, I had one code for the rear sensor. After the install, I end up with codes for both sensors. Driving me nuts!
Thanks, Jake

Jake T

I was very careful during re-assembly. However, you've raised an interesting question. Guess I'll be looking into that tomorrow morning!
Thanks, Jake

Ice95z

The rear knock tends to go bad from water and moisture getting into it. When you push the black grommets back in put a bead of silicone around them to keep the moisture out.

vetteman138

I replaced both knock sensors and harness with Delco parts and still get codes for both sensors. I have ARH headers and LS6 intake on. I called ARH and they told me the headers should not be a problem. Is there any way to check what is causing this problem?

Ice95z

It's a problem with the wiring I suspect. Especially to get codes for both sensors. Like said before check for pinched wires. Your running the correct coolant cross overs for the ls6 intake right? Check to make sure the harness is plugged in to the right connector. It sounds silly but it happens

vetteman138

I checked all the plugs and wires and still get both KScodes. Could my ARH headers be setting the codes?And if so , is there anything I can do to correct the problem?

Ice95z

The headers will not give you knock sensor codes. If the computer is giving you these codes then it means that there is a fault in the knock sensor circuit. Either wiring or the sensors themselves. If the headers were giving you knock counts it would mean that the sensors are working. It would not trip a fault for the knock sensor circuit. IMHO pull the plenum, carefully check and ohm out your wiring and find a wiring diagram to determine if your plugged into the right spot. The computer is telling you where the issue is, try not to over analyze it. Good luck

tblu92

Here is a good site to diagnose codes---
http://www.gearchatter.com/viewpost13096.php
Typically LT headers won't cause Knock codes--However with LT's because of the thinner wall thickness they will pick up some new noises that the ECM will interpret as knock---- called"false spark retard"--The cure is to de-sensize the sensors somewhat with a tune

vetteman138

I unpluged the PCM and checked the ohm and volts at the plug for both sensors. I got the correct ohms for both and when i set meter to volts i hit the motor on both ends and got .5 volts. Still getting both codes. I put never seize on the threads when i installed the sensors. Since i'm getting a good ohm reading that should not be a problem. Helpme please.

Ice95z

Unplug and Ohm the harness, not the entire circuit. Then verify its plugged into the right connector. If your still unsure mock up your own harness. Try unscrewing the sensors a turn. Very rare you have a pcm issue.

vetteman138

what should the knock sensor voltage be at the PCM with the motor running? I'm doing some tests with the old sensors. I made an alum. block and i'm going to try different torque with never seize and without. I'm using an electric engraver to get different vibrations. Since i'm getting a low signel , i'm trying to see what is best.

Bill Curlee

Here is the DTC troubleshooting guide for the knock sensor.. Measure the KR circuit for BOTH detectors and make sure that the resistance falls with in the specified range (93-107K ohms)

If it were me, i would heck the circuits from the PCM connector to make sure that the entire circuit fall with in spec.

Make SURE that the female pins in the connector are not spread apart.


DTC P0327 Knock Sensor (KS) 1 Circuit



Circuit Description
The knock sensor (KS) system detects engine detonation. The PCM retards the spark timing based on the signals from the knock sensors. The knock sensors produce an AC voltage. The knock sensor voltages are an input to the PCM. The amount of AC voltage produced is proportional to the amount of knock.

An operating engine produces a normal amount of engine mechanical vibration (noise). The knock sensors produce an AC voltage signal from this noise. When an engine operates, the PCM learns the minimum and maximum frequency of the noise the engine produces. When the PCM determines that this frequency is less than or greater than the expected amount, a knock sensor DTC sets.

Conditions for Running the DTC
The engine speed is between 1650 RPM and 3000 RPM.
The MAP is less than 49 kPa (7.1 psi).
The engine coolant temperature is greater than 60°C (140°F).
The throttle angle is greater than the idle throttle angle.
The engine has been operating for longer than 20 seconds.
Conditions for Setting the DTC
The PCM determines that this frequency is less than or greater than the expected amount for less than 3.0 seconds.

Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL and the DTC.
Diagnostic Aids

Important
Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

Inspect the knock sensor for proper installation. A knock sensor that is loose or over torqued may cause DTC P0327 to set.
The knock sensor jumper harness is located at the left rear of the intake manifold near the crankcase vent.
For an intermittent, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.

This verifies the malfunction is present. The scan tool will display DTC Ran=Yes and Pass=Int if the failure is intermittent. This indicates the diagnostic passed this ignition cycle and failed this ignition cycle. At this point the resistance of the knock sensors should be verified to be in the correct range. If the knock sensor resistances are correct, inspect the KS system wiring connections. When inspecting the KS system connections, start at the KS system jumper harness connector located behind the intake manifold. Then inspect the connections at the PCM. Refer to the wiring schematic for the correct connector and terminal. Then inspect the connections at the appropriate knock sensor. Failure Records data does not include the parameter KS Activity, however other parameters may aid in locating the conditions under which an intermittent occurred.

This test isolates the Knock Sensor from the rest of the circuit.

Tap on the engine block in the location of the appropriate knock sensor.

Step
Action
Values
Yes
No

1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important
If an engine knock can be heard, repair the engine mechanical condition before proceeding with this diagnostic.


Turn ON the ignition with the engine OFF.
Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
Turn OFF the ignition for 15 seconds.
Start the engine.
Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in Freeze Frame and/or Failure Records as possible. Special operating conditions that you need to meet before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number with the scan tool.
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 behind the intake manifold.
Measure the resistance of the appropriate knock sensor by connecting the DMM between the knock sensor signal circuit on the sensor side and the engine block with the DMM .
Set the DMM to the 400K ohm scale.
Is the resistance of the knock sensor within the specified range?
93-107Kohms
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 AC voltage scale.

Important
Do not tap on plastic engine components.


Tap on the engine in the area of the appropriate knock sensor while observing the signal indicated on the DMM .
Is any signal indicated on the DMM while tapping on the engine near the Knock Sensor?
--
Go to Step 5
Go to Step 7

5
Disconnect the PCM connector C1 located on the same side as the manufacturer's logo. 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
If you find a circuit condition, repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 10
Go to Step 8

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 back of the intake manifold, and the knock sensor connector. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.
If a condition is located repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 10
Go to Step 7

7
Replace the Knock Sensor. Refer to Knock Sensor (KS) Replacement .

Is the action complete?
--
Go to Step 10
--

8
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 terminal as necessary. Refer to Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 10
Go to Step 9

9

Important
Program the replacement PCM.


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

Is the action complete?
--
Go to Step 10
--

10
Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option with the scan tool.
Start the engine and idle at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number with the scan tool.
Operate the vehicle within the conditions for running this DTC as specified in the supporting text, if applicable.
Does the scan tool indicate that this test ran and passed?
--
Go to Step 11
Go to Step 2

11
Select the Capture Info option and the Review Info option with the scan tool.

Does the scan tool display any DTCs that you have not diagnosed?
--
Go to the applicable DTC table
System OK



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Document ID# 554279
2000 Chevrolet/Geo Corvette