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Chevy man
Chevy man, Chevy Technician
Category: Chevy
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Experience:  ASE Certified as an L1 Master Technician with extensive experience in Chevy products
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my 2001 2500hd chevy silverado with the 6.0L engine is ...

Resolved Question:

my 2001 2500hd chevy silverado with the 6.0L engine is suffering from loss of power,and excessive engine knock. So far I have replaced the following:fuel filter,spark plugs,plug wires,and a 1 of my catalytic convertors that was 50% clogged. The only engine code is for a knock sensor. The truck has 130,000miles on it and is an automatic with 4wd.Any sollutions?
Submitted: 7 years ago.
Category: Chevy
Expert:  Chevy man replied 7 years ago.

You have excessive engine knock and a code for a knock sensor.

Why are you ignoring this?

Customer: replied 7 years ago.
Reply to Chevy man's Post: I figured the knock sensor code was set by whatever is causing the problems I am having, not by the knock sensor itself being faulty,I suppose if the knock sensor is bad it could cause my symptoms?
Expert:  Chevy man replied 7 years ago.

The code means the knock sensor circuit has a problem and is not working.

This could be a bad sensor or something else in the circuit. The job of this sensor to to tell the computer when knocking occurs so the computer can retard the timing and stop it.

There is actually a TSB on this problem with the knock sensors. There are 2 of them and they are under the intake manifold. Because of the way the rear one is designed, it get water into the valley where it's located. The TSB addresse a fix for this by building a little dam around the sensor with silicone as shown in the picture below. Design the dam the way it is shown in the picture with it open in the back.

graphic

Customer: replied 7 years ago.
Reply to Chevy man's Post: what do you think the probability of it being a bad sensor versus faulty circuitry,and how can I check this before I take the intake off?
Expert:  Chevy man replied 7 years ago.

Here is the complete flow chart for a PO332

 

 

CIRCUIT DESCRIPTION
The Knock Sensors (KS) produce an AC signal under 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 range, a Diagnostic Trouble Code (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, P1122, or P1258, are not set.
The minimum noise level must be learned. The minimum noise level is learned when the following conditions are met:
The ECT must be greater than 60°C (140°F) .
The engine RPM is between 475-975 for 10 seconds .
Engine speed is between 1500 RPM and 3,000 RPM .
Map is less than 49 kPa .
Engine Coolant Temperature (ECT) is more than 60°C (140°F) .
Throttle angle is more than 0 percent .
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 signal 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.
Use a scan tool in order to clear the MIL and the DTC.
DIAGNOSTIC AIDS

IMPORTANT: If the knock sensor is dropped, it must be replaced.



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 left rear side of the intake manifold.
For an intermittent, Refer to Intermittent Conditions. See: Diagnostic Strategies\Intermittent Conditions
TEST DESCRIPTION

graphic

 

graphic

 

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


This verifies the malfunction is present.
This test will isolate the knock sensor from the rest of the circuit.
Tapping on the engine block will simulate an engine knock.

Chevy man, Chevy Technician
Category: Chevy
Satisfied Customers: 4942
Experience: ASE Certified as an L1 Master Technician with extensive experience in Chevy products
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