P0330 – Knock Sensor 2 Circuit Malfunction (Bank 2) means the engine control unit has detected an electrical problem in the knock sensor circuit assigned to Bank 2. Knock Sensor 2 monitors vibration caused by detonation on the opposite side of the engine from Knock Sensor 1. When this circuit fails, the ECU cannot properly adjust ignition timing for that bank, leading to reduced performance and potential engine knock. This guide explains what P0330 means, symptoms, causes, diagnostics, and the best repair solutions.
What Does P0330 Mean?
P0330 is a generic OBD-II code indicating that Knock Sensor 2 on Bank 2 is not sending the expected voltage signal to the ECU. The sensor may be failing, the wiring may be damaged, or the connection may be loose or corroded. Because the knock sensor protects the engine from detonation, the ECU responds to this fault by retarding ignition timing to prevent possible damage.
This code appears most often on V6 and V8 engines where two knock sensors are used — one per cylinder bank — though some inline engines may reference Bank 2 differently depending on design.
Quick Reference
- OBD-II Family: P-Code (Powertrain)
- Scope: Generic
- System: Knock Sensor / Ignition Timing
- Difficulty Level: Moderate
- Estimated Repair Cost: €90–€380+
- Last Updated: 10 December 2025
Real-World Example / Field Notes
A V6 sedan arrived with sluggish acceleration and poor fuel economy. Scan tool data showed no knock activity on Bank 2, even under heavy load. The Knock Sensor 2 wiring was corroded inside the connector due to a coolant leak dripping onto the harness. Cleaning the connector and sealing the leak restored normal sensor function.
Another case involved an SUV with repeated P0330 after an engine overhaul. Knock Sensor 2 had been overtightened, causing internal damage to the piezo element. Replacing the sensor and using proper torque resolved the code permanently.
Symptoms of P0330 – Knock Sensor 2 Circuit Malfunction
- Reduced engine power: ECU retards ignition timing to prevent detonation.
- Poor acceleration: Noticeable especially during heavy load.
- Poor fuel economy: Due to reduced timing advance.
- Possible pinging/knocking: If timing is inconsistent across cylinder banks.
- Engine hesitation: Occurs during transitions in throttle.
- Check engine light: Typically stored immediately when the circuit fault is detected.
Common Causes of P0330
Most Common Causes
- Failed Knock Sensor 2 (internal piezo failure)
- Damaged or corroded sensor wiring harness
- Loose, broken, or corroded connector pins
- Incorrect torque or improper sensor mounting
- Poor engine ground connection
Less Common Causes
- Coolant or oil contamination in the connector
- Damaged block surface affecting vibration transfer
- Incorrect fuel octane or pre-ignition causing false knock readings
- Engine noise from mechanical issues
- ECU knock control circuit failure (rare)
Diagnosis: Step-By-Step Guide
Diagnosing P0330 involves verifying sensor output, wiring integrity, proper mounting, and checking for real detonation or internal signal interference.
Tools You’ll Need
OBD-II scanner with knock data, multimeter, torque wrench, wiring diagrams, mechanic’s stethoscope, and basic hand tools.
- Review freeze-frame data: Check RPM, load, timing advance, and temperature.
- Inspect Knock Sensor 2 wiring: Look for corrosion, coolant contamination, or broken insulation.
- Check connector integrity: Ensure tight terminal fit and no moisture inside.
- Test sensor resistance: Compare resistance with manufacturer specifications.
- Monitor live data: Knock activity on Bank 2 should change with throttle input.
- Check sensor torque: Tighten to factory specification only.
- Inspect block surface: Ensure clean, flat metal-to-sensor contact.
- Verify engine grounding: Weak grounds distort knock sensor signals.
- Check for real detonation: Fuel quality or timing issues may contribute.
- Check for ECU updates: Some vehicles have knock control calibration updates.
Pro Tip: If Bank 1 knock sensor works normally but Bank 2 does not, swap sensors between banks (if accessible). If the fault follows the sensor, the sensor is bad. If not, wiring or ECU faults are more likely.
Possible Fixes & Repair Costs
- Replace Knock Sensor 2: €70–€180
- Repair or replace wiring or connectors: €50–€150
- Correct mounting torque / clean sensor contact surface: €0–€50
- Improve engine ground connection: €20–€80
- Seal or repair coolant/oil leaks near wiring: €40–€200
- ECU reflash (rare cases): €50–€120
Can I Still Drive With P0330?
Yes, the vehicle will typically still run, but performance will be reduced due to retarded timing on Bank 2. Driving with this code for extended periods is not recommended because inaccurate knock detection increases the risk of detonation under load. Avoid towing, steep hills, and high RPM until the issue is repaired.
Related Codes
- P0399 – Ignition Coil “R” Primary/Secondary Circuit
- P0364 – Reserved
- P0363 – Misfire Detected Fueling Disabled
- P0362 – Ignition Coil “L” Primary/Secondary Circuit
- P0361 – Ignition Coil “K” Primary/Secondary Circuit
- P0360 – Ignition Coil “J” Primary/Secondary Circuit
- P0359 – Ignition Coil “I” Primary/Secondary Circuit
- P0358 – Ignition Coil “H” Primary/Secondary Circuit
- P0357 – Ignition Coil “G” Primary/Secondary Circuit
- P0356 – Ignition Coil “F” Primary/Secondary Circuit
Key Takeaways
- P0330 indicates a malfunction in Knock Sensor 2 on Bank 2.
- Most issues are caused by wiring damage, connector corrosion, or a failed sensor.
- Driving is possible but risky under load due to reduced knock protection.
- Proper sensor torque and clean wiring frequently fix the issue.
FAQ
Is P0330 serious?
Moderately. The engine is protected by retarded timing, but real knock may not be detected, especially under heavy load.
Does Bank 2 always refer to the passenger side?
No. Bank 2 refers to the side of the engine that does not contain cylinder 1. Always refer to the manufacturer’s layout.
Can bad fuel cause P0330?
Bad fuel can cause knock, but P0330 specifically indicates an electrical fault in the knock sensor circuit.
Is replacing the sensor enough?
Only if the sensor itself is bad. Wiring, torque, and connector issues must also be checked.
Why does coolant contamination cause this code?
Coolant can enter connectors, increasing resistance and distorting low-voltage knock sensor signals.