Knock Sensor 1 Circuit Malfunction (Bank 1)
The knock sensor detects engine vibrations caused by detonation (knocking). When the Powertrain Control Module (PCM) detects a fault in the sensor's circuit—such as an open, short, or signal out of range—it sets code P0325. This can lead to reduced engine performance, as the PCM may retard ignition timing to protect the engine, potentially causing power loss and decreased fuel economy.
01. Most Common Causes
- Faulty knock sensor
- Wiring or connector issues (open, short, corrosion)
- Engine mechanical noise (e.g., worn bearings, loose components) causing false signals
- PCM failure (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power and acceleration
- Poor fuel economy
- Engine knocking or pinging under load
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect knock sensor wiring and connector for damage, corrosion, or loose connections.
Step 3: Test knock sensor resistance and signal with a multimeter or oscilloscope per manufacturer specs.
Step 4: Check for engine mechanical issues (e.g., excessive noise) that could trigger false knock readings.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances. The PCM may retard timing, reducing power and fuel economy, and continued driving could lead to engine damage if actual knocking occurs.
How much does it cost to fix?▼
Typically $50-$150 for a DIY replacement of the sensor; labor at a shop can add $100-$200, totaling $150-$350.