Hearing engine knock during hard acceleration in your 2021 Genesis G70 is concerning—especially when accompanied by P0325 (Knock Sensor 1 Circuit Malfunction). Understanding whether you're dealing with a sensor issue or actual detonation is critical for proper diagnosis.
Understanding P0325
Code P0325 indicates a problem with the knock sensor circuit—not necessarily actual engine knock. The sensor detects detonation and signals the ECU to retard timing. When the circuit fails, the ECU can't monitor for knock effectively.
Knock Sensor Function
Knock sensors are microphones that detect the specific vibration frequency of detonation. When knock is detected, the ECU reduces ignition timing to prevent engine damage. The G70's turbocharged engine is particularly sensitive to knock control.
Symptoms to Evaluate
- Audible pinging or knocking under load
- Check engine light with P0325
- Possible reduced power (ECU protective mode)
- Poor fuel economy
- Rough running under acceleration
Possible Causes
Knock Sensor Failure
The sensor itself can fail from age, heat exposure, or internal breakdown.
Wiring Problems
Damaged, corroded, or disconnected wiring to the sensor triggers circuit codes.
Actual Detonation
Low-octane fuel, carbon buildup, or excessive boost can cause real knock independent of sensor function.
Sensor Mounting Issues
Loose mounting affects sensor sensitivity and accuracy.
Repair Costs
| Repair | Parts | Labor | Total |
|---|---|---|---|
| Knock sensor replacement | $75-$200 | $200-$400 | $275-$600 |
| Wiring repair | $25-$75 | $150-$300 | $175-$375 |
| Carbon cleaning (if needed) | $50-$100 | $400-$700 | $450-$800 |
Critical Distinction
Determine whether the audible knock is real or if P0325 is simply a sensor/circuit issue. Real knock damages engines; sensor failures just limit the ECU's ability to detect and protect against knock.