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P2336 — Cylinder 1 Above Knockcombustion Vibration Sensor Threshold

Manufacturer-specificPowertrain (engine & transmission)

Code P2336 indicates that the engine computer has detected a vibration signal from the cylinder 1 knock sensor that exceeds the normal threshold. This means the system is either experiencing actual engine detonation (knock) or the sensor itself is reporting a false high signal due to a circuit or component failure.

Symptoms

What causes it — most likely first

1. Faulty knock sensor

The sensor itself can degrade or short internally, causing it to send an excessively high or constant voltage signal to the engine computer.

2. Wiring or connector issues

Corroded, frayed, or loose wiring in the knock sensor circuit can cause electrical interference or false high readings that trigger the code.

3. Actual engine detonation

Legitimate pre-ignition or detonation from low-octane fuel, severe carbon buildup, or a lean air-fuel mixture will naturally push vibration levels past the threshold.

4. Incorrect sensor installation

A knock sensor that is loose, over-torqued, or lacks proper dielectric grease can vibrate erratically or transmit false signals to the engine computer.

5. PCM/ECM failure

A failure within the engine computer's internal circuitry is extremely rare but could theoretically cause it to misinterpret the sensor voltage.

How it's diagnosed

  1. Scan for additional codes, particularly lean condition codes (like P0171) or misfire codes, which point to actual engine detonation rather than a sensor failure.
  2. Visually inspect the cylinder 1 knock sensor wiring harness and connector for fraying, corrosion, or loose pins.
  3. Verify the knock sensor is correctly torqued to the engine block and properly grounded, as an improper install causes false readings.
  4. Test the knock sensor resistance and signal output using a digital multimeter and an oscilloscope to confirm if its readings are out of factory spec.
  5. If the sensor and wiring test normally, investigate mechanical causes of actual knock, such as carbon buildup or fuel system restrictions.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is it safe to drive with code P2336?

It can be driven briefly with caution, but prolonged driving is risky. If the engine is legitimately knocking, it can cause severe internal damage. Even if it is a false reading, the computer will likely retard ignition timing to protect the engine, resulting in sluggish performance.

Do I need to replace the PCM to fix P2336?

No, replacing the PCM is almost never the correct fix. Many mechanics or online sources may suggest a computer replacement, but this code is overwhelmingly caused by a defective knock sensor, wiring faults, or actual engine knock, rather than a faulty engine computer.

Can the wrong type of fuel cause this code?

Yes. Using a lower octane fuel than the manufacturer recommends can cause severe pre-ignition and detonation, which the knock sensor detects as vibration above the normal threshold, setting the code.

Why does my car lack power when this code is active?

When the computer detects high vibration from the knock sensor, it actively retards the ignition timing to prevent engine damage. This protective measure significantly reduces engine power and acceleration.