Error Code P0333: What It Means & What To Do?

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A P0333 code is a generic Diagnostic Trouble Code, thus it applies to all makes of vehicles, and refers to a high output voltage of the knock sensor. This code refers to the sensor on bank #2 (the side of the engine that doesn't contain cylinder #1). The P0333 code means that the input voltage from a knock sensor circuit in one of the cylinders on bank 2 is higher than the manufacturer’s limitation. However, your vehicle will likely require multiple instances to set the code. This code is usually seen in conjunction with other, more serious issues.

OBD-II Code P0333 is defined as a Knock Sensor 2 Circuit High. It indicates that the PCM has detected a voltage input reading in the knock sensor circuit for a particular cylinder that is not within a predetermined manufacturer’s limit. Typical knock sensor circuits consist of one 5-volt signal wire. If voltage readings exceed a variation of 10-percent from the manufacturer’s reference voltage, a code will be stored in the PCM and a malfunction indicator lamp will be illuminated. The knock sensor tells the engine control module (PCM) that the engine has an excessive vibration resulting from an incorrect fuel and air mixture. If the PCM does not receive a signal from the knock sensor, it will set code P0333. Code P0333 pertains to the sensor on bank 2 (the opposite side of the engine where the #1 cylinder is located).

While the P0333 code will not always result in drivability problems, it is important to have it inspected immediately as it may lead to serious damage and higher repair cost.

What causes the problem of Knock Sensor 2 Circuit High Input (Bank 2)?

• Faulty knock sensor
• Loose knock sensor
• Damaged knock sensor connector
• Open or shorted knock sensor circuit
• knock sensor circuit is shorted to voltage
• Circuit has electrical problem
• Low fuel pressure
• Inaccurate fuel octane
• Failed PCM

1. Knock Sensor - The knock sensor (KS) is mounted in the engine and is used to detect spark knock. The knock sensor detects vibrations upon increase and decrease in engine rpm. Ensure its efficient functioning else can lead to the associated trouble codes.
2. Connectors - Connectors here refers to a device that usually used to join the electrical circuits. These are really the one of the small components but actually play an important role in smooth running of your expensive automobile. Make sure they should not be damaged or corroded else replace them immediately.
3. Shift Solenoid - Shift solenoid or transmission solenoid is an electro-hydraulic valve that controls fluid flow into and throughout an automatic transmission. If you discover it frayed, kindly replace it.
4. Powertrain Control Module - A powertrain control module (PCM), also known as the engine control unit (ECU) or module (ECM), is electronic devices that regulates many of a vehicle’s important functions and has a direct impact on how well the car runs. So, always ensure its proper functioning.

Below are the common symptoms for the code P0333. If you experience below mentioned symptoms please bring your vehicle to a reputable repair facility. Keep in mind; problems don’t get better over time unless rectified.

• Detectable knocking from the engine compartment
• Pinging from engine under acceleration
• Dropping power
• Improper RPM
• MIL (Malfunction Indicator Lamp) illumination

P0333 code will not always result in drivability problems but it is important to have it inspected immediately because it may cause more serious engine problems in near future, which can lead to serious damage and higher repair costs. The repair needed to fix the P0333 code will vary depending on the underlying cause of the problem. Below mentioned repairs or replacements that can help you fix this trouble code:

• Repair the frayed connectors
• Replace or repair the damaged wiring
• Replace the faulty knock sensor
• Repair of more serious engine problems causing the P0333 code

Below are some basic steps to diagnose the trouble code P0333, though we always recommend you to have it diagnose from an experienced technician.

• Many problems can easily be found in the harness and connectors. So, begin your diagnosis by visually inspecting the sensor and its connection.
• Perform a basic test of the knock sensor. Locate the knock sensor and tap on an engine location near the sensor (do not directly strike the sensor). If the sensor is working correctly, you should see the timing begin to retard. If not, you have a problem with the sensor or its circuit.
• Connect a digital multimeter set to AC voltage between the knock sensor output signal wire and a good ground. Then once again, tap on an engine location near the sensor. You should see an AC voltage reading on your digital multimeter. If not, the sensor is bad and should be replaced.
• If the knock sensor checks out OK, but you still have P0333 code illuminated, you’ll need to check the sensor circuit. Using a digital multimeter set to the ohms; connect one side of the meter to the harness side of the knock sensor connector and the other to the knock sensor input pin on the PCM. This tests the continuity between the sensor and PCM. If your meter reads OL, there is an open somewhere in the circuit that must be repaired. If not, the PCM is likely the problem and should be replaced.

Common Mistakes When Diagnosing the P0333 Code

Common causes of misdiagnosis include replacement of the knock sensor when another more serious engine malfunction is to be blamed. Make sure that the knock sensor is not simply “doing its job” before replacing it.