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OBD2.help›Powertrain›P0328

P0328

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

The engine computer is seeing a knock-sensor signal that is higher than expected. That can happen when the sensor or wiring is faulty, the connector is contaminated, or the engine has real knock or vibration that is overwhelming the signal. The computer may pull timing to protect the engine.

SEV
3/5
DRIVE
CAUTION
DIY
$20-$150
SHOP
$150-$600

Quick answer

AI-CITATION READY

What it means

P0328 means the PCM detected an abnormally high input from knock sensor 1, usually on bank 1 or on engines with a single knock sensor. The signal can be too high because of sensor failure, wiring or shielding problems, connector contamination, or true engine knock and vibration. Many vehicles respond by retarding ignition timing, which can reduce power and fuel economy.

Can you drive with it?

With caution. You may be able to drive short distances, but reduced timing and power are common. If the engine is pinging, running rough, or overheating, do not keep driving until it is diagnosed.

Most common causes

  • Faulty knock sensor 1 sending an abnormally high signal
  • Damaged, poorly shielded, or shorted wiring in the knock sensor 1 circuit
  • Oil, coolant, or water contamination in the connector or harness

Typical repair cost

DIY usually runs $20-$150. Typical shop repair lands around $150-$600, depending on the root cause.

01 / Definition

P0328 means the PCM detected an abnormally high input from knock sensor 1, usually on bank 1 or on engines with a single knock sensor. The signal can be too high because of sensor failure, wiring or shielding problems, connector contamination, or true engine knock and vibration. Many vehicles respond by retarding ignition timing, which can reduce power and fuel economy.

02 / Drive status

With caution. You may be able to drive short distances, but reduced timing and power are common. If the engine is pinging, running rough, or overheating, do not keep driving until it is diagnosed.

03 / Symptoms

  • Check engine light on
  • Reduced engine power
  • Poor acceleration
  • Possible spark knock or pinging
  • Lower fuel economy
  • Timing retard visible on scan data

04 / Causes

1Faulty knock sensor 1 sending an abnormally high signalhigh
2Damaged, poorly shielded, or shorted wiring in the knock sensor 1 circuithigh
3Oil, coolant, or water contamination in the connector or harnessmedium
4Real engine knock, detonation, or severe mechanical vibrationmedium
5PCM input problemlow

05 / Diagnostic sequence

  1. 01Check for related codes first, especially misfire, cooling-system, lean-mixture, or timing-related faults.
  2. 02Inspect the knock sensor 1 connector and harness for contamination, corrosion, damaged shielding, or rubbed-through wiring.
  3. 03Verify the sensor is mounted securely and is the correct part number.
  4. 04Use a scan tool to review timing retard and knock sensor activity under different engine conditions if supported.
  5. 05Test the circuit for shorts to voltage, signal noise, and resistance problems according to the service manual.
  6. 06Inspect the engine for real causes of high knock activity such as low-octane fuel, overheating, carbon buildup, incorrect spark plugs, or internal noise.
  7. 07If wiring and engine condition are good, replace the sensor and confirm the high-input condition does not return.

06 / Repairs

1Repair damaged wiring, shielding, or connector faults in the knock sensor 1 circuit$20-$150
2Clean contaminated connectors and correct any ground or routing problems in the harness$10-$120
3Replace the knock sensor 1 if it produces an abnormally high signal$50-$250
4Correct real knock causes such as poor fuel, overheating, carbon buildup, or mechanical noise$10-$600
5Diagnose PCM input faults if the external circuit and engine condition test good$150-$900

07 / Related codes

  • P0325
  • P0326
  • P0327
  • P0330
  • P0332
  • P0300

08 / FAQ

What does high input mean on P0328?

It means the PCM is seeing a knock sensor signal that is stronger or noisier than expected.

Can real detonation trigger P0328?

Yes. True knock or severe engine vibration can push the knock sensor signal high enough to set the code.

Will P0328 make the engine feel weak?

Often yes. The computer may pull ignition timing to protect the engine, which reduces power.

09 / Source and method

DATA BASIS
OBD-II REFERENCE + OBD2.HELP
METHOD
STATIC VALIDATION
SAFETY
INFORMATIONAL

This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.

Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.

Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.