P0332 – Knock Sensor 2 Circuit Low Input (Bank 2) means the engine control unit has detected a knock sensor signal that is lower than expected for Knock Sensor 2 on Bank 2. This sensor monitors detonation on the opposite side of the engine from Bank 1. When the signal stays too low, the ECU cannot detect knock accurately and may retard ignition timing to protect the engine. This guide explains the meaning of P0332, symptoms, causes, diagnostic steps, and the most effective repair methods.
What Does P0332 Mean?
P0332 is a generic OBD-II powertrain code indicating that Knock Sensor 2 on Bank 2 is producing a voltage signal below the ECU’s minimum expected threshold. Knock sensors generate small voltage pulses when they detect engine vibration caused by detonation. A low input typically means the sensor is not detecting vibration correctly due to electrical problems, loose mounting, or internal sensor failure.
Because the ECU relies on knock data to adjust ignition timing, a low signal can cause reduced engine performance and decreased fuel efficiency.
Quick Reference
- OBD-II Family: P-Code (Powertrain)
- Scope: Generic
- System: Knock Sensor / Ignition Timing Control
- Difficulty Level: Easy–Moderate
- Estimated Repair Cost: €90–€320+
- Last Updated: 10 December 2025
Real-World Example / Field Notes
A V8 sedan came in with a lack of power and a persistent P0332. The knock sensor wiring for Bank 2 had been pinched between the intake manifold and bracket after previous engine work, causing high resistance and a weak signal. Repairing the damaged wiring restored proper readings and eliminated the code.
Another common case involves oil contamination from valve cover leaks. Oil seeped into the knock sensor connector, reducing signal quality and causing the ECU to read “low input.” Cleaning the connector and replacing the gasket fixed the issue.
Symptoms of P0332 – Knock Sensor 2 Low Input
- Reduced power: ECU retards timing to compensate for missing knock feedback.
- Poor acceleration: Noticeable under load or during uphill driving.
- Lower fuel economy: Due to reduced spark advance.
- Pinging or knocking: ECU may not detect detonation accurately.
- Hesitation or rough performance: Particularly during throttle transitions.
- Check engine light: Triggered when the signal remains below threshold.
Common Causes of P0332
Most Common Causes
- Failed Knock Sensor 2
- Damaged or corroded wiring or connector
- Poor sensor-to-block contact (rust, dirt, oil)
- Loose or improperly torqued sensor
- High resistance in the signal circuit
Less Common Causes
- ECU internal fault (rare)
- Excessive engine carbon buildup reducing noise feedback
- Aftermarket tuning altering knock sensitivity
- Real knock not occurring (rare but possible interpretation issue)
- Improper engine block resurfacing affecting vibration transfer
Diagnosis: Step-By-Step Guide
Diagnosing P0332 involves confirming sensor voltage patterns, checking wiring integrity, and ensuring proper mounting on the engine block.
Tools You’ll Need
OBD-II scanner with knock monitoring, multimeter, torque wrench, wiring diagrams, and basic tools.
- Check freeze-frame data: Review load, RPM, temperature, and timing advance at fault time.
- Monitor live knock sensor data: Compare Bank 1 and Bank 2 signals.
- Inspect wiring: Look for cracked insulation, pinched wires, or corrosion.
- Inspect connector: Ensure clean, dry terminals with proper tension.
- Check sensor torque: Incorrect torque often causes low input faults.
- Test sensor resistance: Compare with the manufacturer’s specifications.
- Clean mounting surface: Rust or dirt dampens vibration transfer.
- Check engine grounds: Weak grounding distorts low-voltage knock signals.
- Inspect for oil leaks: Oil contamination affects connector performance.
- Check for ECU updates: Some vehicles benefit from updated knock control calibration.
Pro Tip: If the Bank 1 knock sensor works perfectly but Bank 2 reads low, swapping the sensors can quickly identify whether the fault is the sensor or the wiring.
Possible Fixes & Repair Costs
- Replace Knock Sensor 2: €70–€180
- Repair wiring or connector: €50–€150
- Retorque sensor correctly: €0–€50
- Clean mounting surface or remove rust: €0–€40
- Repair engine grounds: €20–€80
- ECU reflash (rare): €50–€120
Can I Still Drive With P0332?
Yes, short trips are generally safe, but performance will be reduced due to conservative timing. However, long-term driving is not recommended because the ECU cannot detect knock reliably on Bank 2. Avoid towing, steep hills, or aggressive driving until the issue is fixed.
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
- P0332 means Knock Sensor 2 on Bank 2 is producing a signal lower than expected.
- Wiring issues, poor mounting, or a failed sensor are the most common causes.
- Driving is possible but risky under load due to reduced knock protection.
- Cleaning contacts and verifying torque often resolves low-input conditions.
FAQ
Is P0332 serious?
Moderately. The engine may not detect detonation properly, especially under high load.
Does low octane fuel cause P0332?
No. Low octane causes knock, but P0332 refers to an electrical low-signal condition.
Is the knock sensor bad?
Not always. Wiring damage, corrosion, or poor mounting can also cause low input.
Can I clear the code and keep driving?
The code may clear temporarily, but it will return if the underlying issue persists.
Should I replace both knock sensors?
It’s optional, but many technicians replace both on high-mileage V6/V8 engines since they tend to fail around the same time.