How to reset check engine light

Check engine light on ? What code ? There are many different (DTC'S) - diagnostic trouble codes that can set for knock sensors ! There all don't mean that you replace the sensor .
DTC P0324: Knock Sensor (KS) Module Performance
DTC P0325: Knock Sensor (KS) Circuit Bank 1
DTC P0326: Knock Sensor (KS) Performance
DTC P0327: Knock Sensor (KS) Circuit Low Bank 1
DTC P0328: Knock Sensor (KS) Circuit High Bank 1
DTC P0330: Knock Sensor (KS) Circuit Bank 2
DTC P0332: Knock Sensor (KS) Circuit Low Bank 2
DTC P0333: Knock Sensor (KS) Circuit High Bank 2

The knock sensor (KS) system enables the control module to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The sensors are located below each cylinder head on the engine block. The KS produces an AC voltage signal that varies depending on the vibration level during engine operation. The control module adjusts the spark timing based on the amplitude and the frequency of the KS signal. The control module receives the KS signal through 2 isolated signal circuits. The control module learns a minimum KS noise level at idle and uses calibrated values for the rest of the RPM range. The control module should monitor a normal KS signal within the noise channel.
Knock Sensor Replacement - Bank 1
Remove the exhaust manifold lower heat shield. Refer to Exhaust Manifold Lower Heat Shield Replacement.
Disconnect the engine wiring harness electrical connector (1) from the bank 1 knock sensor (2).
Loosen the knock sensor bolt and remove the knock sensor.
Knock Sensor Replacement - Bank 2
Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
Remove the engine oil filter. Refer to Engine Oil and Oil Filter Replacement .
Lower the vehicle.
Disconnect the engine wiring harness electrical connector (2) from the bank 2 knock sensor (3).
Loosen the knock sensor bolt and remove the knock sensor.

these are designed to be placed were they are so it will only pick up a knock from the engine and not other things bolted to the engine. just replace the knock sensor were it was designed to work best.

Hi Lee,
I'm not sure if the programming in that particular vehicle will disable traction control and/or cause the cruise control light to flash because of a faulty knock sensor. There is no way for a repair technician to know all the factors behind the software in your system. You MAY have separate problems with the cruise - then maybe not.

The only thing I can tell you for sure is that Subaru knock sensors are prone to failure due to cracking. The outer shell gets cracks in it and then moisture gets in and corrodes the field windings inside the sensor shorting them out. (SEE PICTURE)

"Reflashing" your computer or resetting the codes will not work if this is the case. You will have to replace the knock sensor FIRST, then reset the computer memory.

CARB (California Air Resources Board) has a consistent policy regarding monitoring knock (Ks) sensors but vehicle manufacturers don't have a consistent way of using knock sensor circuitry. There are generally two methods that manufacturers have for using the knock sensor.
In the first design, which is found in most vehicles, the knock sensor plays an active role in controlling ignition timing. In this system, the PCM is advancing ignition timing until knock occurs and then retards timing slightly. This system runs on the verge of engine knock at all times. In this system the function of the knock sensor circuit is critical. If the sensor malfunctioned, precise ignition timing control could not be achieved.

A "dead" sensor circuit would not be able to detect actual knock, timing would be overly advanced, and NOX exhaust emissions would increase. For this reason, manufacturers that use the knock sensor in this manner are required to monitor this sensor and light the MIL light when a malfunction is detected.

In the second design, the knock sensor plays a very passive role and is really only on the engine for protection purposes. The various engine sensors send their information to the PCM to determine ignition timing. The PCM uses this information to control the ignition timing based on look-up tables stored in its memory. If ignition knock is detected, the PCM will take action and ****** the timing a few degrees. This type of control is generally used to control spark knock caused by changes in fuel octane.

Used in this way, the knock sensor is less critical to emissions and may not even have a measurable emission impact. Unlike the first design, a "dead" knock sensor in this system will have little to no effect on the operation of the engine. Manufacturers that use this design are not required to monitor the sensor under EPA OBDII regulations and will not turn on the MIL if the P0325 DTC is set.
Remember, this sensor does not change the operation of the engine. The customer will not notice any change in the way the vehicle operates. The knock sensor system has a one trip detection logic and WILL NOT turn on the MIL or store Freeze Frame data.

How to Diagnose P0325
Most technicians know how this type of sensor operates. Its element produces a voltage when the sensor picks up a vibration, usually caused by engine detonation.Technicians then check the ohmic value of the sensor.
Maybe this was of some help.Your valuable feedback would be appreciated.Thanks for choosing Fixya.

P0327 - Knock Sensor 1 Circuit Low Input Bank 1 or Single Sensor
First check the knock sensor connector. If the connector is clean and secure, replacing the knock sensor usually takes care of the problem.

- An excessively low voltage from the sensor is sent to Powertrain Control Module (ECM) or Engine Control Module (ECM)

The knock sensor is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as vibrational pressure. This pressure is converted into a voltage signal and sent to the Powertrain Control Module (PCM) or Engine Control Module (ECM).

Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/Loss of Power

Possible causes
- Knock sensor circuit short to GND.
- Knock sensor circuit short to PWR.
- Knock sensor circuit open.
- Damaged knock sensor.
- Faulty Powertrain Control Module (PCM) or Engine Control Module (ECM).


Test and check it. Hope helps.

did you have the check engine light reset after replacing it? if not then go to auto zone, and let them know you replaced it and need to reset the trouble light for the check engine light... hope this helps...

Hello. You have posted an excellent question.

The code 55 you are getting, in Toyota terms, as as follows:

"No number one knock sensor signal to the ECU fo four crank revulutions under these 2 conditions: Coolant temperature 140 degrees F or more; Engine speed between 1600 and 5200 RPM."

This indicates a failed (or a loose) knock sensor on the Right Bank of the engine. Since the knock sensor is basically a piezo-electric crystal, not continuity test can be performed with the intake manifold installed.

You can check the continuity form the Knock Sensor wires to the ECM, but, this may not prove useful to you.

Unfortunately, you are going to have to pull the intake, and check the knock sensor wiring integrity. If the connector is good, and the sensor is tight, I would suggest replacing the sensor. Actually, if you were in my shop, I would suggest replacing them both, as the whole intake will have to come off if the other sensor fails. Better to replace them both at once, than to pull the intake again.

We here at FixYa hope that this helps you out, and saves you some future reoair dollars. Thanks for choosing FixYa for advice.

Replace knock sensors

P0332 - Knock Sensor 2 Circuit Low Input (Bank 2)

This sensor signals the engine-control computer when detonation is detected, momentarily retarding ignition timing until detonation ceases.

Most computer-controlled systems use knock sensors to ****** timing when the engine is experiencing pinging or knocking.


Obviously, a faulty knock sensor produces problems that appear to be ignition-system-related. If the knock sensor system does not provide an engine detonation signal to the PCM (powertrain control module), the engine detonates, especially on acceleration.

• The first step in diagnosing the knock sensor and knock sensor module is to check all the wires and connections in the system for loose connections, corroded terminals, and damage.
• With the ignition switch on, be sure that 12 volts are being supplied through the fuse to the knock sensor module.
• A quick check of a knock sensor is to watch the ignition's timing while the engine is running and the engine block is tapped with a hammer.
  • The noise should cause a change in timing.
• The knock sensor can also be checked by tapping near the sensor and watching for an AC pulse on a DMM or lab scope.

Well, you have another issue besides a knock sensor problem. A knock sensor code WILL NOT illuminate the check engine light. Check for other codes stored in the ECU. I have seen oxygen sensor issues cause knock sensor issues due to inaccurate fuel delivery resulting in engine ping at all times (causing the ECU to think that the knock sensor is bad because it's reporting ping at all times) - but also had codes for one or more O2 sensors.

Nissan Scope Technician- 10 years with Nissan