The S2000 knock sensor in your Honda is primarily responsible for monitoring engine knock or detonation. It’s a big part of your Honda EFI system and when this one pin ceramic sensor goes bad, it’s going to trigger a OBDII check engine light. The most common Honda S2000 issue with your Diagnostic Trouble Code is P0325.
Most S2000 knock sensor issues in your 2.0 liter F20C engine trigger a limp mode. Your S2000 won’t be able to rev higher than a certain point and it won’t respond to your accelerator input.
If your Honda S2000 check engine light is on, you’ll need a OBDII scan tool to pull the code out from your ECU.
If your trouble code comes back as an alphanumeric check engine light for your knock sensor, this guide can help you test it.
To begin testing your knock sensor, go ahead and clear your Honda S2000 check engine light using your scan tool. Now start your Honda S2000 engine and increase the engine speed between 3,000-4,000 RPM. If your S2000 knock sensor is faulty the check engine light should immediately return.
If it does immediately light back up, the first part of this S2000 knock sensor tutorial starts with testing for continuity between the ECU and knock sensor harness. Stop your engine and reach behind your intake manifold to access your knock sensor.
Unplug the knock sensor and use a digital multimeter to test for continuity. The wire you will need to check is the RED wire with a BLUE stripe of the knock harness to your ECU. The ECU plug in question is your 31pin Honda S2000 ECU C connector.
If there is continuity the next part of the test is to ground the knock sensor harness. There’s not much else to test for this sensor, as it’s a one pin unit and very simple in design.
Knock sensors are just piezoelectric listening devices, much like a microphone. Inside your S2000 knock sensor there’s a special piece of ceramic that creates an electric signal from vibration.
If your sensor has died, it’s either failed from the heat inside your engine bay or your ceramic has cracked. To proceed we’ll be testing the ground from your S2000 knock sensor.
Connect a ground or run a wire into the female side of the S2000 knock sensor connector. Now check the same C connector of your S2000 ECU, PIN 22 and make sure there’s a ground signal.
If a ground signal is present at this ECU wire, this means that unfortunately your knock sensor has gone out. Remove the knock sensor and then install your replacement unit to correct your P0325 trouble code.
Once you have the knock sensor installed, you’ve got to use your OBDII scan tool to clear and erase your S2000 check engine light. Have any questions about this How To Guide? Want more tech tips and DIY articles for your Honda S2000? Subscribe to My Pro Street and get all the latest in tutorials and automotive news.