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Dan
Dan, Auto Technician
Category: Chevy
Satisfied Customers: 3490
Experience:  GM Mark of Excellence/ Service Guild Participant with 13 years experience, ASE Master Certified
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2003 chevy: litre .....my check engine light came..my engine

Resolved Question:

i have a 2003 chevy z71 5.3 litre.....my check engine light came on and i brought it some where and they told me it was either my knock sensor is bad, the wires goign to it are bad, there is something making noise in my engine, or something with the fuel system....i changed my fuel filter and it starts good and ever=ything so i dont think its my fuel pump......where is the knock sensor located and can it make your truck run rough at all if it is bad
Submitted: 7 years ago.
Category: Chevy
Expert:  Dan replied 7 years ago.

I would need the trouble code(s) to determine exactly was wrong with it. If the knock sensor were bad it may make the engine run like it lacks power due to the computer not adjusting the timing accordingly. The knock sensors for this engine are located in the valley under the intake manifold. There is a bulletin pertaining to the knock sensors failing put out by GM.

 

Customer: replied 7 years ago.
Reply to Dan's Post: i have a programmer if i send u the trouble codes think u can help me ?
Expert:  Dan replied 7 years ago.
Yes, I can follow the diagnostic trouble tree for that code and hopefully get you the solution...send it on over.
Customer: replied 7 years ago.
Reply to Dan's Post: p0332
Customer: replied 7 years ago.
Reply to Dan's Post: thanks but if u dont mind think u could explain to me what the code means like what should i do
Expert:  Dan replied 7 years ago.
DTC P0327 or P0332
Circuit Description
The knock sensor (KS) system enables the powertrain control module (PCM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The system uses two KS located under the intake manifold. KS 1 is located at the front of the engine. KS 2 is located at the back of the engine. Each KS produces an AC voltage that varies depending on the vibration level during engine operation. The PCM adjusts the spark timing based on the amplitude and frequency of the KS signal. The PCM receives a signal from each KS through a signal circuit. The KS ground is supplied by the engine block through the sensor housing. The PCM uses each KS signal to calculate an average voltage range value. If the KS system is operating normally, the PCM should monitor the KS voltage varying above and below the voltage range. If the PCM detects the KS signal voltage within the voltage range, or the KS signal is not present, a DTC will set. DTC P0327 refers to the front KS. DTC P0332 refers to the rear KS.

Conditions for Running the DTC
   • DTCs P0117, P0118, or P0125 are not set.

   • The minimum noise level must be learned. The minimum noise level is learned when the following conditions are met:

      - The engine coolant temperature (ECT) must be greater than 60°C (140°F).

      - The engine speed is between 475-975 RPM for 10 seconds.

   • The engine speed is between 1,500-3,000 RPM.

   • The manifold absolute pressure (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.

   • The ignition voltage is more than 10 volts.

Conditions for Setting the DTC
   • The PCM detects that the KS signal is within the calculated voltage range or the KS signal is not present.

   • The above conditions are met 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
   • 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.

   • Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set.

   • Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material.

   • For an intermittent condition, refer to Intermittent Conditions .

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

This step ensures that the malfunction is present.

This step tests the KS and the KS jumper harness for an open or a short to ground.

Tapping on the engine block will simulate an engine knock.

Step
Action
Values
Yes
No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views

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

2
Important: If an engine mechanical noise can be heard, repair the condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical - 4.8L, 5.3L, and 6.0L.


Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Does the DTC fail this ignition?
--
Go to Step 3
Go to Diagnostic Aids

3
Remove the left engine sight shield. Refer to Engine Sight Shield Replacement in Engine Mechanical - 4.8L, 5.3L, and 6.0L.
Disconnect the knock sensor (KS) jumper harness connector located on the left side of the intake manifold.
Set the DMM to the 400 K-ohm scale.
Measure the resistance from the affected KS signal circuit on the sensor side of the KS jumper harness connector to a good ground with the DMM.
Is the resistance within the specified range?
93-107K ohms
Go to Step 4
Go to Step 6

4
With the DMM still connected, set the DMM to the 400 mV AC hertz scale.
Important: Do not tap on plastic engine components.


Tap on the engine block with a nonmetallic object near the affected KS while observing the signal indicated on the DMM.
Is any signal indicated on the DMM while tapping on the engine block near the KS?
--
Go to Step 5
Go to Step 7

5
Disconnect the PCM.
Test the affected KS signal circuit between the PCM and the KS jumper harness connector for the following conditions:
   - An open

   - A short to ground

   - A short to voltage

   - A high resistance Refer to Testing for Continuity , Testing for Short to Ground , or Testing for a Short to Voltage in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 12
Go to Step 8

6
Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical 4.8L, 5.3L, 6.0L.
Test the KS signal circuit between the KS jumper harness connector and the KS connector for the following conditions:
   - An open

   - A short to ground

   - High resistance Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 12
Go to Step 7

7
Test for an intermittent and for a poor connection at the affected KS. Refer to Testing for Intermittent Conditions and Poor Connections or Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 12
Go to Step 10

8
Test for an intermittent and for a poor connection at the KS jumper harness connector. Refer to Testing for Intermittent Conditions and Poor Connections or Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 12
Go to Step 9

9
Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections or Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 12
Go to Step 11

10
Replace the affected KS. Refer to Knock Sensor (KS) Replacement .

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

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

Is the action complete?
--
Go to Step 12
--

12
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Does the DTC fail this ignition?
--
Go to Step 2
Go to Step 13

13
Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List
System OK



--------------------------------------------------------------------------------
Customer: replied 7 years ago.
Reply to Dan's Post: so since that dtc is reported it will make my truck run a lil worst than normal??? and i have been running my truck with this dtc for about a month and nothing else went wrong except that it runs a lil rough.....that means nothing should be wrong with mew engine and that i prolly just need to change this sensor correct?
Expert:  Dan replied 7 years ago.
Yes, if the harness and connector are both ok then the knock sensor is probably faulty. It will cause the computer to run on base timing so ignition advance won't take place. This will create loss of horsepower and fuel mileage, pinging in the engine and the check engine light (trouble code).
Dan, Auto Technician
Category: Chevy
Satisfied Customers: 3490
Experience: GM Mark of Excellence/ Service Guild Participant with 13 years experience, ASE Master Certified
Dan and 4 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.
Reply to Dan's Post: awsome well i appreciate the help thanks so much

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