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P0328 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P0328 is an OBD-II Code that refers to Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)

Meaning

A P0328 code is caused by an ECM (Engine Control Module) receiving a signal from the bank 1 knock sensor 1 that there is a high input. When out of range of manufacturer specifications, the ECM will store the code.

Causes

Common causes for this code include:

  • Faulty knock sensor
  • Open in wiring to knock sensor 1 circuit
  • Short to voltage in the knock sensor 1 signal circuit
  • Faulty ECM
  • Engine overheats
  • Fuel octane rating too low for the engine
  • Running out of fuel
  • Low fuel pressure or lean mixture

Symptoms

The symptoms of a P0328 code are:

  • Check Engine Light will be illuminated
  • Poor fuel economy 
  • Rough idle 
  • Power Loss
  • Knocking or pinging sounds

Diagnosis

To diagnose a P0328 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Listen for knocking sounds that might be coming from engine
  3. Visual inspection for any flaws
  4. Any faults in the cooling system or engine need to be investigated
  5. If the engine is knocking, inspect the fuel octane and fuel system.
  6. Check the knock sensor voltage for changes

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0328 code:

  • Not checking for faults in the cooling system or engine in general 
  • Not checking for proper fuel octane and pressure
  • Not allowing enough time in Freeze Frame to look at all parameters and not just first two.

How serious is this?

Although a P0328 code is not the worst of codes, it does indicate a fault and needs to be repaired. It is likely that many cylinders are misfiring or failing. This can impede fuel economy and lower engine performance. 

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Replacing Bank 1 Knock Sensor 1 
  • Replacing ECM
  • Fixing problems with the fuel
  • Repairing any possible faults with the coolant system

Related codes

A P0328 is related to and may be accompanied by the following codes: 

P0325 – Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)

P0326 – Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)

P0327 – Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)

Conclusion

In conclusion, the P0154 code is a generic trouble code that is mostly caused by a faulty knock sensor. Another common cause of this code is a short in the wiring or voltage supply to knock sensor 1 or an actual failure in the knock sensor itself. 

The best way to diagnose this code is through diagnostic testing and visual inspection. It can be difficult for technicians to find faults in these particular sensors but continued monitoring will give clues as to what specific component may be causing the problem.