P0325: Knock Sensor Circuit Malfunction (Bank 1)
P0325 forces the engine to run conservative timing, sacrificing power and fuel economy.
Severity: moderate · System: Powertrain · Safe to drive: usually, short-term. Fix soon — ECU pulls timing to protect the engine, hurting MPG.
Symptoms
- Reduced power
- Pinging sound
- Poor fuel economy
Common causes
- Failed knock sensor
- Wiring damage
- Loose sensor
Fair repair prices
| Knock sensor replacement | $250–$650 |
|---|---|
| Wiring repair | $100–$300 |
Ranges are US market averages (parts and labor). If your shop's quote is above the high end, ask for a line-item breakdown or run it through the invoice checker.
Other codes
- P0300 — Random / Multiple Cylinder Misfire Detected
- P0301 — Cylinder 1 Misfire Detected
- P0420 — Catalyst System Efficiency Below Threshold (Bank 1)
- P0430 — Catalyst System Efficiency Below Threshold (Bank 2)
- P0171 — System Too Lean (Bank 1)
- P0174 — System Too Lean (Bank 2)
- P0442 — Evaporative Emission Control System Leak (Small)
- P0455 — Evaporative Emission Control System Leak (Large)