📟
P0328 means the knock sensor signal is stuck high - typically caused by a short to voltage in the sensor circuit. The ECM sees higher voltage than expected and retards timing. Check wiring before replacing the sensor. See top-rated scanners on Amazon ↗
🗺️ Where Is the Problem?
Blueprint view - P0328 knock sensor 1 high voltage fault, Bank 1
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0328 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
45%
#1 - Most Likely
Short to Voltage in KS Circuit
A chafed wire contacting a powered circuit drives the signal voltage above the ECM expected range. Inspect harness near the sensor for heat damage, abrasion, or pinched wires.
🔩 Part
$20–$80
👨🔧 Labor
$60–$150
⚡ DIY Difficulty
Medium
40%
#2 - Check First
Failed Knock Sensor Sending High Signal
The internal sensor element has failed in a mode generating continuously elevated voltage output. Measure sensor output voltage with a multimeter.
🔩 Part
$30–$120
👨🔧 Labor
$80–$200
⚡ DIY Difficulty
Medium
15%
#3 - Less Common
Wiring Chafing on Chassis Ground
A wire chafed to chassis creates leakage paths that confuse high/low voltage readings. Inspect harness clips and routing for wear points.
🔩 Part
$15–$50
👨🔧 Labor
$40–$100
⚡ DIY Difficulty
Medium
10%
#4 -
Contaminated or Wet Connector
Water intrusion creates a parasitic voltage path. Dry and inspect the connector, apply dielectric grease, and reseat before replacing parts.
🔩 Part
$0–$20
👨🔧 Labor
$0–$40
⚡ DIY Difficulty
Easy
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Inspect Connector and Wiring - Locate the knock sensor on the engine block. Unplug the connector, inspect for corrosion and bent pins, clean with contact cleaner, and reseat firmly. Clear the code and retest before purchasing any parts.
- Test Knock Sensor Resistance - With the connector unplugged, measure resistance across knock sensor terminals with a multimeter. Piezoelectric sensors should read very high resistance (1 MΩ+). A low or zero reading indicates a failed sensor element.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need