OBD-II Code P0330 — What It Means & How to Fix It

What Does This Error Mean?

P0330 means there is a fault in the knock sensor 2 circuit. Knock sensor 2 monitors the second bank of cylinders — typically bank 2 on V6 and V8 engines. The PCM uses this sensor to detect detonation and protect the engine by retarding timing. Without it, you may lose power as the PCM retards timing across bank 2 as a precaution.

Affected Models

All 1996+ V6 and V8 vehicles with dual knock sensors
Common in Toyota and Lexus V6 engines (bank 2 sensor)
Common in GM LS-series V8 engines with two knock sensors
Common in Nissan and Infiniti V6 and V8 engines
Common in Ford V6 and V8 engines with two-sensor knock systems

Common Causes

Failed knock sensor 2 with an open circuit or internal breakdown
Damaged, corroded, or broken wiring in the bank 2 knock sensor circuit
Loose mounting of knock sensor 2 preventing proper vibration detection
Corroded or loose harness connector at the sensor 2 plug
Actual engine knock on bank 2 causing repeated signal spikes that the PCM flags as a circuit fault

How to Fix It

Confirm which bank of your engine is bank 2. On most vehicles, bank 1 contains cylinder 1 and bank 2 is the opposite bank. For example, on a GM V8, bank 2 is the passenger-side bank. Check a diagram specific to your vehicle.

Getting bank 1 and bank 2 mixed up is a common mistake. Replacing the wrong sensor wastes time and money.
Locate knock sensor 2. It is threaded into the engine block on the bank 2 side, typically beneath the intake manifold. On many engines this requires intake manifold removal to access. Check for visible wiring damage before planning the teardown.

On Toyota and Lexus V6 engines, both knock sensors are accessible together under the intake manifold. This makes access labor-intensive but allows you to inspect both sensors at once.
Inspect the knock sensor 2 wiring harness. Look for heat damage, chafing, or broken wires. Check the connector for corrosion, bent pins, or moisture intrusion. Clean the connector with electrical contact cleaner and reconnect.

Wiring for sensors under the intake manifold is often disturbed during previous engine work. Check for pinched or misrouted wires from prior repairs.
Test the sensor by measuring its resistance. Unplug the harness connector and measure across the sensor's two terminals with a multimeter. Compare the reading against your vehicle's service manual specification. A reading significantly out of spec indicates sensor failure.

If you are replacing the sensor on a Toyota or Lexus V6, many technicians replace both knock sensors at the same time since access requires the same labor for both.
Install the new knock sensor and torque to the manufacturer's specification — typically 15-20 Nm. Do not overtighten. Clear stored fault codes and perform a test drive with varying engine load to confirm P0330 does not return.

After replacement, the PCM will resume normal timing advance on bank 2 after a few warm drive cycles.

When to Call a Professional

If replacing knock sensor 2 and inspecting wiring does not resolve P0330, the PCM or a wiring harness short may be at fault. A technician can test signal output with an oscilloscope and check the circuit integrity precisely. Diagnosis typically costs $80-$130. Knock sensor 2 replacement runs $100-$350 depending on the engine and access difficulty.

Frequently Asked Questions

Why do some engines have two knock sensors?

V6 and V8 engines have two banks of cylinders. One knock sensor monitors each bank independently. This allows the PCM to retard timing on just the knocking bank. The other bank continues operating at full efficiency. Two sensors provide better protection and more precise timing control.

Can P0330 appear alone or does it come with other codes?

It can appear alone if only bank 2's sensor circuit has a fault. You will not necessarily see any misfire codes with P0330. If the engine has real knock on bank 2, you might see both P0330 and timing-related codes. Check for all stored codes together to get the full picture.

Is P0330 urgent?

It is moderately urgent. The PCM protects the engine by retarding bank 2 timing as a precaution. This reduces power and fuel economy but prevents knock damage. However, if actual engine knock exists on bank 2, the damage risk is real. Do not delay diagnosis if you also hear engine noise.