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Overview

P0328 OBD-II Knock Sensor 1 Circuit High Input Bank 1 DTC diagnostic fault code meaning symptoms causes and fixes

Common Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Rough or uneven idle
Loss of engine power or hesitation
Engine pinging or knocking noises
Irregular RPM fluctuations

Most Common Causes

Faulty knock sensor high

Sensor may be failing or producing abnormally high voltage responses

Wiring harness damage or connector corrosion high

Frayed, corroded, open, shorted-to-ground or shorted-to-voltage wiring often results in high input readings

ECM/PCM input circuit fault medium

Internal module fault may interpret normal signals as high voltage

True engine knock or detonation medium

Mechanical issues, low octane fuel or lean running can cause actual knock which triggers high sensor output

Diagnostic Steps

Connect OBD-II scan tool and read P0328 along with any related codes

Expected: Code P0328 present, note freeze frame data

Interpretation: Confirm that knock sensor circuit high input is logged
Visually inspect knock sensor connector and wiring harness for damage or corrosion

Expected: Wiring intact with no corrosion or damage

Interpretation: Good condition suggests internal sensor or ECM issue
Measure voltage and resistance of knock sensor circuit with a multimeter

Expected: Voltage within normal operating range (OEM spec) and resistance matching knock sensor spec

Interpretation: Out-of-range values suggest sensor or wiring fault
Temporarily install a known-good knock sensor (if available)

Expected: P0328 code clears when good sensor installed

Interpretation: Original sensor was faulty
If tests above pass, check ECM/PCM input circuit or consult OEM service info for calibration/TSBs

Expected: ECM may fail input tests

Interpretation: Module replacement or reprogramming required

Repair Solutions

Replace knock sensor medium

Estimated Cost: $80 - $300

OEM quality sensor recommended; costs depend on vehicle and access difficulty

Repair wiring harness and connectors medium

Estimated Cost: $50 - $250

Includes repairing frayed wires, replacing corroded connectors, and ensuring proper grounds

Replace or reprogram ECM/PCM hard

Estimated Cost: $300 - $1200

Required only if input circuit fault confirmed

Address underlying engine knock causes (fuel quality, ignition timing, fueling) medium

Estimated Cost: $0 - $500

Correcting lean conditions or using proper octane fuel may resolve actual knock

Common Misdiagnoses

Avoid these common diagnostic mistakes:

Assuming only sensor failure without checking wiring harness or true mechanical knock condition

Frequently Asked Questions

What is the definition of the P0328 engine code?

Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor) is the standard definition for P0328. This diagnostic code is triggered when the ECU detects a problem in the Sensors.

Should I stop driving if I have P0328?

This is a medium priority issue. Check engine light illumination, possible rough idle, loss of power, and irregular RPMs when cruising or accelerating

How do I know if I have code P0328?

You may experience the following: Malfunction Indicator Lamp (MIL) illuminated, Rough or uneven idle, Loss of engine power or hesitation.

What causes the P0328 code?

The most common causes are: Faulty knock sensor, Wiring harness damage or connector corrosion, ECM/PCM input circuit fault.

What is the price difference for fixing P0328?

The cost varies significantly based on the root cause. For example, replacing a Repair wiring harness and connectors typically costs between $50 and $250, while fixing a Replace or reprogram ECM/PCM can range from $300 to $1200.

What cars are affected by the P0328 code?

The P0328 code is a generic powertrain code, meaning it applies to almost all makes and models, such as Honda, Toyota, VW, Ford, and Chevy.

P0328: Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)