Knock Sensor — Replacement (Chevrolet Trailblazer 1)

1. The knock sensor reacts to abnormal engine vibration (occurring during detonation or pre-ignition). By constantly adjusting the ignition phase, maximum engine performance is maintained on the verge of detonation. As detonation develops, the alternating voltage of the sensor pulse increases. After a critical signal is received by the PCM, the ignition phase is delayed and detonation stops. On 6-cylinder in-line engines with a volume of 4.2 liters, there are two knock sensors, which are located at the front and rear walls of the engine. Sometimes, the unjustified use of high-octane gasoline or premium fuel can lead to a malfunction of the knock sensors, which will result in the registration of a malfunction code in the microprocessor memory.

Replacement

Warning: Allow the engine to cool completely before performing this procedure.

2. Disconnect the negative cable from the battery.

3. Raise the vehicle and support it on vertical stands.

4. Disconnect the knock sensor electrical connector (see illustrations).







5. Unscrew the bolt and remove the knock sensor.

6. Installation is carried out in the reverse order of removal. Tighten the mounting bolt to 25 Nm.

(The original text can be found on the website: CHEVYMAN.RU)