Chevrolet Sonic Repair Manual: Knock Sensor System Description
- Circuit/System Description
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The knock sensor system enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The ECM uses the knock sensor system to test for abnormal engine noise that may indicate detonation, also known as spark knock.
- Sensor Description
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This knock sensor system uses one or two flat response dual-wire sensors. The sensor uses piezo-electric crystal technology that produces an alternating current (AC) voltage signal of varying amplitude and frequency based on the engine vibration or noise level. The amplitude and frequency are dependant upon the level of knock that the knock sensor detects. The ECM receives the knock sensor signal through 2 isolated signal circuits.
If the ECM has determined that knock is present, it will retard the ignition timing to attempt to reduce the knock. The ECM is capable of controlling spark retard on an individual cylinder basis. The ECM will always try to work back to a zero compensation level, or no spark retard. knock sensor diagnostics are calibrated to detect faults with the knock sensor circuitry inside the ECM, the knock sensor wiring, or the knock sensor voltage output. Some diagnostics are also calibrated to detect constant noise from an outside influence such as a loose/damaged component or excessive mechanical engine noise.
Knock Sensor Replacement
Knock Sensor Replacement
Callout
Component Name
Preliminary Procedures
Disconnect battery negative cable. Refer to
Battery Nega ...
Heated Oxygen Sensor Replacement - Sensor 1
Heated Oxygen Sensor Replacement - Sensor 1
Callout
Component Name
Warning: In order to avoid being burned, do not service the ...
Other materials:
Storing the Tire Sealant and Compressor Kit
The tire sealant and compressor kit is located in the rear storage area.
1. Lift the trim cover.
2. Remove the tire sealant canister (1) and the compressor (2).
To store the tire sealant canister and compressor:
1. Attach the sealant/air hose to the sealant canister inlet valve.
2. Return the ...
Vehicle Yaw Sensor Learn
The yaw sensor does not require calibration often. Calibration of the yaw rate
sensor might be required after certain service procedures are performed. Some of
these procedures are as follows:
Electronic brake control module (EBCM) replacement
Multi-axis acceleration sensor replacement
...
Intake Camshaft Installation
Note: Mind the markings on the camshaft bearing caps. Camshaft
bearing caps should be installed in their original position.
Lubricate camshaft and camshaft bearing caps with engine oil.
Install the intake camshaft (3).
Install the 5 camshaft bearing caps ...
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