How Knock sensor works?
There are 2 types of KS currently being used: •The broadband single wire sensor •The flat response 2-wire sensor Both sensors use piezo-electric crystal technology to produce and send signals to the PCM. The amplitude and frequency of this signal will vary constantly depending on the vibration level within the engine. Flat response and broadband KS signals are processed differently by the PCM. The major differences are outlined below: •All broadband sensors use a single wire circuit. Some types of controllers will output a bias voltage on the KS signal wire. The bias voltage creates a voltage drop the PCM monitors and uses to help diagnose KS faults. The KS noise signal rides along this bias voltage, and due to the constantly fluctuating frequency and amplitude of the signal, will always be outside the bias voltage parameters. Another way to use the KS signals is for the PCM to learn the average normal noise output from the KS. The PCM uses this noise channel, and KS signal that rides along the noise channel, in much the same way as the bias voltage type does. Both systems will constantly monitor the KS system for a signal that is not present or falls within the noise channel. •The flat response KS uses a 2-wire circuit. The KS signal rides within a noise channel which is learned and output by the PCM. This noise channel is based upon the normal noise input from the KS and is known as background noise. As engine speed and load change, the noise channel upper and lower parameters will change to accommodate the KS signal, keeping the signal within the channel. If there is knock, the signal will range outside the noise channel and the PCM will reduce spark advance until the knock is reduced. These sensors are monitored in much the same way as the broadband sensors, except that an abnormal signal will stay outside of the noise channel or will not be present. KS diagnostics can be calibrated to detect faults with the KS diagnostic inside the PCM, the KS wiring, the sensor output, or constant knocking from an outside influence such as a loose or damaged component. In order to determine which cylinders are knocking, the PCM uses KS signal information when the cylinders are near top dead center (TDC) of the firing stroke.
The Knock Sensor Video
Get an innova digital auto multimeter like the one in the video on Amazon here → http://www.amazon.com/gp/product/B000EVYGZA/ref=as_li_qf_sp_asin_il_tl?ie=U TF8&camp=1789&creative=9325&creativeASIN=B000EVYGZA&linkCode=as2&tag=httpww wyou00f-20&linkId=2KS2TQF5V4QEWODO Thumbs up Mandy's video here → https://www.youtube.com/watch?v=h54AnKbSfyQ See Ericthecarguy's Voltage drop test here → https://www.youtube.com/watch?v=W2cFuheKBgQ Get a suck squeaze bang blow shirt from oily rags here → http://oilyragclothing.com/index.php?route=product/product&path=60_69&produ ct_id=89 See Soham Koli's knock sensor slide show here → http://www.slideshare.net/SohamKoli/knock-sensor The Knock Sensor Video
Tip Clip: Knock Sensor Testing
Dave Scaler from MEA presents testing tips on the most popular import models your customers drive today. Learn quick & surefire ways to diagnose and fix the toughest problems in this growing portion of your repair business. Check it out at http://www.auto-video.com/import-testing-techniques-p-3.html
P0325 Knock Sensor Diagnosis - EricTheCarGuy
Visit me at: http://www.ericthecarguy.com/ Wells website http://www.wellsve.com/ Wells YouTube (great videos I recommend you subscribe) http://www.youtube.com/user/markjhicks As you can see by the title this video covers the diagnosis and repair of a P0325 on my 1997 Subaru Legacy L model with 2.2L engine backed by an auto trans. I did have some trouble with the 'factory' diagnostic procedure but thankfully my friend Mark at Wells Electronics had a test that involved a voltage drop across the sensor that worked perfectly. I hope this video illustrates the import ants of understanding a circuit that you're diagnosing as opposed to just throwing parts at something, with a little time and effort you can do a proper diagnosis. --- Click below and Stay Dirty Visit me at EricTheCarGuy.com http://ericthecarguy.com/ Visit EricTheCarGuy Forum http://www.ericthecarguy.com/forum/default.aspx Visit my Facebook Page: http://www.facebook.com/EricTheCarGuy --- Stay dirty ETCG Due to factors beyond the control of EricTheCarGuy, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. EricTheCarGuy assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. EricTheCarGuy recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of EricTheCarGuy, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not EricTheCarGuy.