Code P0237 Knock Sensor location needed

Tiny
NTHORNBURY
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
I have a ticking while idling and driving, and I also received a p0237 code for a knock sensor. Where exactly are the knock sensors located on this model? I was also wondering if a bad water pump can cause the ticking or failing spark plugs? Thank you.
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Friday, March 26th, 2021 AT 9:53 AM

4 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good evening,

There is no 237 code but there is a 327 code for the knock sensor. I attached the flow chart and schematic for this code below for you to view.

https://www.2carpros.com/articles/how-a-knock-sensor-works

Let me know if you have any other questions.

Roy

REMOVAL PROCEDURE

CAUTION: Refer to Battery Disconnect Caution in Cautions and Notices.

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1. Disconnect the negative battery cable.
2. Raise the vehicle.
3. Remove the Knock Sensor harness connector.

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4. Remove the Knock Sensor (2) from the cylinder block (1).

INSTALLATION PROCEDURE

Circuit Description
The Control Module (PCM/VCM) uses the Knock Sensor(s) (KS) in order to detect engine detonation. Ignition Control (IC) spark timing is retarded based on the KS signal input when spark knock is detected. The Control Module monitors normal engine background noise during warm engine operation. It stores these noise values for comparison to the current knock sensor signal to help discriminate between normal engine noise and knock. If the amount of noise is below the minimum stored noise value, this DTC will set.

Conditions for Running the DTC
No active ECT sensor DTCs
No active TP sensor DTCs
The timing retard is 0 degrees or less
The system voltage is between 10-17 volts
The ECT is 60 C (140 F) or more
The engine run time is 120 seconds or more
The knock sensor noise is less than 3 counts
The engine speed is 2000-3000 RPM
The throttle position is more than 6 percent

Conditions for Setting the DTC
The difference between the actual noise value and the learned minimum noise value is less than 50 counts or more than 200 counts

Action Taken When the DTC Sets
The Control Module illuminates the Malfunction Indicator Lamp (MIL) if a failure is detected during 2 consecutive key cycles.
The Control Module will set the DTC and records the operating conditions at the time the diagnostic fails. The Control Module stores the failure information in the scan tools Freeze Frame and/or the Failure Records.

Conditions for Clearing the MIL/DTC
The Control Module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22 C (40 F) from the start-up coolant temperature and the Engine Coolant Temperature is more than 70 C (158 F) during the same ignition cycle).
Use the scan tool Clear Information function.

Diagnostic Aids
Check for the following conditions:
A misrouted harness. Inspect the knock sensor harness in order to ensure that it is not routed too close to high voltage wires such as spark plug leads.
Improper knock sensor torque specification. Torque the knock sensor to 19 N.m (14 lbs ft). Refer to Component Tightening Notice in Service Precautions.

Review the Fail Records vehicle mileage since the diagnostic test last failed for help determining how often the conditions occur that caused the DTC to set. This may assist in diagnosing the condition.

An intermittent may be caused by any of the following conditions:
A poor connection
Rubbed through wire insulation
A broken wire inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittent and Poor Connections Diagnosis. See: Computers and Control Systems > Symptom Related Diagnostic Procedures

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Ensures that the condition is present.
5. Ensures that the knock sensor is capable of detecting detonation. Striking the lift bracket with a non-metallic object should produce a signal that the knock sensor should detect.
7. Ensures that the 5 volt reference is near the specified value without being more than 5.2 volts.
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Friday, March 26th, 2021 AT 4:08 PM
Tiny
NTHORNBURY
  • MEMBER
Sorry about that, I transposed the numbers. Thank you for the additional info. This will be helpful. Thanks again!
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Friday, March 26th, 2021 AT 8:03 PM
Tiny
STEVE W.
  • EXPERT
A common reason for that code is the wiring has rubbed through near the exhaust and it sends the wrong data to the ECM. I would check the harness for damage first.
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Saturday, March 27th, 2021 AT 12:18 AM
Tiny
ASEMASTER6371
  • EXPERT
You are welcome.

Just like Steve said, check the wiring before replacing the sensor.

Roy
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Saturday, March 27th, 2021 AT 4:30 AM

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