The knock sensor is commonly located on the engine block and essentially listens for improper combustion when the engine is running. Engine knock, or spark knock, is the noise created when the combustion process is erratic or abnormal. Code p0330 indicates that the knock sensor has picked up a frequency outside of the factory-set frequency range for the combustion chamber. The computer uses information from the knock sensor to adjust the engine ignition timing to keep combustion within the safe zone of operation. In general, when the knock sensor code is set, the computer will put the engine into limp mode to help prevent engine damage.
The ignition system is made up of the spark plugs, plug wires, ignition coil, distributor cap and distributor rotor. Some vehicles have one ignition coil, and spark is distributed by the distributor. Vehicles without a distributor include either a coil pack setup, where the plug wires are connected directly to the coil pack, or a coil over plug setup, where each spark plug has its own coil pack and there is no plug wire. On vehicles without a distributor, the spark timing is controlled in whole by the computer. If any of the ignition components are worn or faulty, the spark may be erratic, causing spark knock and setting off code p0330. If the ignition coils on any of the three systems are faulty, it will cause spark knock, which will set code p0330.
The distributor is rotated in sync with the engine cam shaft. If the distributor timing is offset, the spark will not be delivered at the optimal time, causing combustion to take place when the piston is still in the process of the compression or exhaust stroke. This not only causes spark knock but can be very damaging to the engine valves and pistons. If the terminals on the distributor cap or distributor rotor are worn, the current transferred from the ignition coil to the plug wire will be dramatically reduced. When improper current is delivered to the spark plug, the spark will not be strong enough to properly create combustion.
Remove and inspect each individual spark plug and inspect it for wear at the ground strap and center electrode. If the spark plug is excessively worn or otherwise damaged, the engine will not receive the proper spark, which will create spark knock. If the spark plugs have recently been changed, it is also possible the spark plug gap is set incorrectly, which will hamper the combustion process. Inspect each individual plug wire for cracks in the wire coating or boot. If the plug wires are not properly routed and cross each other, current can jump from one wire to the other, causing the spark plug to fire at the wrong time.
Improper fuel delivery, whether it is from clogged fuel injectors, a weak fuel pump, a clogged fuel filter or damage to a fuel line, can all result in less fuel getting into the combustion chamber. When the air and fuel mixture is off, the combustion will be erratic. Check under the vehicle for any fuel leaks and run fuel-injector cleaner to help clear up the fuel filter and fuel injector jets. It can also be a good idea to replace the fuel filter, because it is generally inexpensive. If there is a lack of air entering the engine, there will be too much fuel for the amount of air. Inspect the air filter by holding it up to the light. If light is not visible through the paper media, it needs to be replaced.
Before replacing the knock sensor, inspect the knock sensor wiring. If the wires are burned or damaged from road conditions, the computer may be receiving inaccurate information. Inspect the terminals on both the knock sensor and the wiring harness for corrosion or damage. If nothing to this point has corrected the code fault, replace the knock sensor.
