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:
Headlining Trim Panel Replacement (Sedan without Sunroof)
Headlining Trim Panel Replacement
Callout
Component Name
Warning: Do not attempt to repair or alter the head impact
energy-absorbing material glued to the headliner or to the garnish trims.
If the material is damaged ...
Toe Description
Toe is a measurement of how much the front and/or rear wheels are turned in or
out from a straight-ahead position. When the wheels are turned in, toe is positive (+).
When the wheels are turned out, toe is negative (−). The actual amount of toe is
normally only a fraction ...
Camshaft Installation
Special Tools
EN-422 Installer
For equivalent regional tools, refer to Special Tools.
Note: Coat with MoS 2 lubricating paste. Refer to Adhesives, Fluids,
Lubricants, and Sealers.
Install the intake camshaft (1).
Note: Note the identification mark ...
0.0084