Code P0327 (Symptoms, causes and how to fix it)

As most motorists know, anything mechanical in nature will break down from time to time, and our beloved vehicles are no exception. Although today’s vehicles tend to be much more reliable than those of yesteryear, they are still far from immune to occasional difficulties, which often occur at the worst of times.

To make matters worse, the average motorist has to wonder about the source of the vehicle’s mechanical problems, in the absence of a simple answer. Fortunately, those who own an older vehicle from 1996 or later are provided with specialized error codes to assist in the diagnostic process. These codes are stored in a vehicle’s onboard diagnostic system for later review.

One of those error codes is DTC P0327, which indicates a problem with the vehicle’s knock sensor circuit. This sensor notifies the engine management software of a “ping” or “knock” that occurs when combustion is not ideal.

Read on to learn more about DTC P0327 and how to fix these problems, should they occur in the future.

What does the P0327 code mean?

The P0327 diagnostic trouble code refers to a low voltage condition in a vehicle’s knock sensor circuit. Specifically, this code refers to the No. 1 engine bank knock sensor, on engines with a “V” configuration.

However, to better understand the severity of DTC P0327, you must first familiarize yourself with the theory behind how the knock sensor works.

Most modern vehicles are equipped with what is called a “knock” sensor. Sensors of this type monitor motor harmonics to identify and isolate any irregularities.

When functioning properly, the engine knock sensor warns the motorist of abnormal engine vibration by illuminating the vehicle’s check engine light. Most knock-detection events come from peripheral combustion.

In the case of DTC P0327, the engine management software believes that the sensor in question cannot provide accurate information. This, in turn, reduces the vehicle’s ability to decide between normal and abnormal engine vibrations, making it slightly more vulnerable to additional wear and tear.

Related: Code P0325, Code P0332

Code P0327 Symptoms

The P0327 diagnostic trouble code is usually accompanied by several additional symptoms, most of which vary in severity. Recognizing these symptoms is often helpful when trying to identify the root cause of these problems.

These are some of the most common symptoms associated with DTC P0327.

Additionally, there are some cases where the P0327 diagnostic trouble code is not accompanied by any additional symptoms, although this is extremely rare.

Causes of code P0327

The P0327 diagnostic trouble code can be caused by many underlying problems, and some tend to be more common than others. Understanding these possible causes can help you repair your vehicle faster.

These are some of the most common causes of DTC P0327.

Is code P0327 serious?

Compared to other trouble codes, DTC P0327 is often considered a moderate priority. In general, there is little risk of further damage from driving with an active P0327 fault code.

This is because this code is less indicative of operational problems than a specific sensor failure. Simply put, the P0327 code specifies the relative inability of the vehicle’s knock sensor to function as intended.

Likewise, the feedback provided by a vehicle’s knock sensor has little to do with the subsequent ECM/PCM calculation, meaning this data is not critical to efficient engine operation. A malfunctioning knock sensor is unlikely to prevent a vehicle from operating at an adequate level of efficiency.

However, one should take the time to diagnose and repair the root cause of the vehicle’s P0327 trouble code, when practical. Such repairs restore knock sensor operations, eliminating your vehicle’s annoying check engine light in the process.

How to fix code P0327

The following steps can be used to diagnose and repair the root cause of your vehicle’s active P0327 diagnostic trouble code. As always, be sure to consult a specific factory service manual (print or online) for your particular vehicle before proceeding with such repairs.

#1: Check for additional DTCs

Before starting the diagnostic process, check for additional diagnostic error codes. Any such codes present must be thoroughly diagnosed before proceeding.

#2 – Knock Sensor Wiring Inspection

Start by inspecting the knock sensor in question, as well as any associated wiring. During such inspection, it is also a good idea to check the integrity of the corresponding sensor connector. Any damage or irregularity must be corrected immediately.

#3 – Check Power/Ground

Next, check that the affected knock sensor has power and ground inputs (as specified by the vehicle manufacturer), using a quality digital multimeter. If either power supply is missing, additional troubleshooting of the input circuit will be required.

#4 – Resistance test

You can now remove the knock sensor in question and test its effective resistance. Most manufacturers specify that sensors of this design should have a resistance greater than 0.5 ohms. Anything below this resistance level will require sensor replacement.

#5: Check Sensor Feedback

Assuming your vehicle’s knock sensor resistance is within specifications, an oscilloscope will be needed to read and detect feedback from the sensor itself.

All comments must reflect manufacturing specifications and not deviate from the shape or length of the contour waveform. If no abnormalities are found in these observations, it is likely that the PCM/ECM is defective or failing.