Knock Sensor 1 Circuit High Input
The P0328 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the knock sensor (Bank 1 or single sensor) that is higher than the expected range. This typically points to a wiring issue, such as a short to voltage, a faulty sensor, or a problem with the ECM. The knock sensor detects engine vibrations caused by detonation (knock) and sends a signal to the ECM to adjust ignition timing. A high input can cause the ECM to incorrectly retard timing, reducing performance and fuel economy.
1. Most Common Causes
- Faulty knock sensor
- Short to voltage in knock sensor circuit
- Damaged wiring or connector
- Corroded terminals
- Faulty ECM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power and acceleration
- Poor fuel economy
- Engine knocking or pinging noise
- Possible rough idle
3. 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 shorts.
Step 3: Test knock sensor resistance and voltage with a multimeter (typically 2-4 kΩ and 2.5V bias).
Step 4: Check for short to voltage by disconnecting sensor and measuring signal wire voltage (should be 0V with key on).
Step 5: If wiring is good, replace knock sensor and clear codes.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the ECM may retard timing excessively, leading to reduced performance, poor fuel economy, and potential engine damage from undetected knock.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts (knock sensor $50-$150) and labor (1-2 hours).
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.