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:
Wheels and Trim—Aluminum or Chrome
Use a soft, clean cloth with mild soap and water to clean the wheels. After rinsing
thoroughly with clean water, dry with a soft, clean towel. A wax may then be applied.
Caution
Chrome wheels and other chrome trim may be damaged if the vehicle is not washed
after driving on roads that have bee ...
Radiator Cleaning
Warning: NEVER spray water on a hot heat exchanger. The resulting
steam could cause personal injury.
Caution: The heat exchanger fins are necessary for good heat transfer.
Do not brush the fins. This may cause damage to the fins, reducing heat transfer.
Note: Blow compressed ...
Engine Oil Cooler Inlet Pipe Replacement (LUW)
Removal Procedure
Drain the cooling system. Refer to Cooling System Draining and Filling.
Remove the exhaust manifold with catalytic converter. Refer to Exhaust
Manifold with Catalytic Converter Replacement.
Remove the engine oil cooler pipe bolts (1) an ...
0.0082