What Does P0329 Mean?
Knock sensor 1 circuit is exhibiting intermittent signal behavior. The PCM detects that the knock sensor signal periodically drops out, spikes unexpectedly, or becomes erratic. This prevents reliable knock detection and causes the PCM to apply inconsistent timing corrections. The driver may notice occasional hesitation or momentary power loss as the PCM alternately retards and advances timing.
Common Causes
30%
Loose or corroded knock sensor connector with intermittent contact
25%
Knock sensor wiring with intermittent break due to vibration fatigue
20%
Knock sensor becoming loose over time, causing intermittent coupling with the engine block
15%
Knock sensor beginning to fail internally with temperature-dependent intermittent output
10%
Intermittent shield ground connection allowing periodic noise pickup
Diagnostic Steps
1
Perform a thorough wiggle test on the knock sensor connector and wiring while monitoring the knock sensor PID — move the harness at 6-inch intervals and watch for signal disruption.
2
Check the knock sensor connector terminals for corrosion, spread pins, or signs of overheating. Repair or replace the connector if any issues are found.
3
Verify the knock sensor mounting torque — use a torque wrench to check if it has loosened from vibration. Retorque to specification.
4
Monitor the knock sensor signal over an extended drive using the scan tool's data logging feature — capture the signal pattern during the intermittent event to correlate with speed, temperature, or road conditions.
5
If the connector and wiring test good, replace the knock sensor as internal intermittent failures are common in aging piezoelectric sensors.
Estimated Repair Cost
$80 - $350
Parts + labor, varies by vehicle and location
Knock sensor 1 circuit is exhibiting intermittent signal behavior. The PCM detects that the knock sensor signal periodically drops out, spikes unexpectedly, or becomes erratic. This prevents reliable knock detection and causes the PCM to apply inconsistent timing corrections. The driver may notice o...
The most common cause of P0329 (Knock Sensor 1 Circuit Input Intermittent (Bank 2 or Single Sensor)) is: Loose or corroded knock sensor connector with intermittent contact
Typical repair costs for P0329 range from $80 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive for normal conditions. The intermittent nature means the knock detection system works most of the time. Avoid sustained heavy-load driving until repaired. Schedule the repair within a reasonable timeframe to ensure consistent knock protection.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0329 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition / Knock Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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