Chevrolet Sonic Repair Manual: Knock Sensor System Description
- Circuit/System Description
-
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
-
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:
Instrument Panel Center Trim Panel Replacement
Instrument Panel Center Trim Panel Replacement
Callout
Component Name
1
Instrument Panel Center Trim Panel (Qty:?€‰2)
Procedure
Use a flat bladed plastic trim tool in order to disengage the retainers
secur ...
Tire and Wheel Assembly Balancing - Off Vehicle
Warning: Failure to adhere to the following precautions before tire
balancing can result in personal injury or damage to components:
Clean away any dirt or deposits from the inside of the wheels.
Remove any stones from the tread.
Wear eye protection.
Use coated weights on alum ...
Cleanliness and Care
An automobile engine is a combination of many machined, honed, polished, and
lapped surfaces with tolerances that are measured in ten thousandths of an inch.
When any internal engine parts are serviced, care and cleanliness are important.
A liberal coating of engine oil should be applied to fr ...
0.0089