OBDII Mode 6: How Significant Is It?

Bluedriver is an OBD2 scanner Mode 6
Bluedriver is an OBD2 scanner Mode 6

OBDII, as what we all know, is a very important user interface in cars, because it can help technicians easily detect problems.

Most of the time, these possible issues or even the current ones are made imminent by a warning light on the car’s dashboard.

With the help of scan tools, technicians can save time diagnosing and repairing problems related to the anti-lock brake system, air bags, engine, and more.

For those who don’t know, OBDII scanner is integrated with nine standard modes of operation that are used by scan tools to perform different functions. One of them is Mode 6 which specifically shows data for non-continuous monitors.

In this article, we will briefly discuss OBDII Mode 6 is and its significance in car diagnostics and repair.

What is OBDII Mode 6

OBDII Mode 6 is one of the OBDII modes defined by the Environmental Protection Agency (EPA) and by the Society of Automotive Engineers (SAE).

What is OBDII Mode 6As indicated by both organizations, Mode 6 contains “test results for continuously and non-continuously monitored systems.”

To get a clearer understanding about what Mode 6 does, this is how it works:

A vehicle performs some tests on its systems and components like on the evaporative emission control system (EVAP), catalytic converter, and the oxygen sensors.

Once the test results are already available, they are saved by the engine computer in Mode 6. This is where a scan tool looks for results that would help technicians determine if a car is going to pass an emission test or not.

In the simplest sense, OBDII Mode 6 can be referred to as a technician’s virtual door to the car manufacturer’s “electronic strategy.” Whatever criteria or parameters that the software engineer was thinking during the development of the car, like for example the Check Engine Lights, can be basically seen on Mode 6.

One important thing to know about Mode 6 is that its functionality is defined by every car manufacturer, thus it differs depending on the make and model. Moreover, not all scan tools are designed to support it.

Note: For more information about the other OBDII modes and their operations, one may refer to the “SAE On-Board Diagnostics for Light and Medium Duty Vehicles Standards Manual” which is available on the Service Technicians Society’s website.

Why Does OBDII Mode 6 Have Varying Views from Technicians?

Technicians, who’ve seen the inception of Mode 6 in cars in the early 2000s, may have varying views about how helpful it is or how limited its usage may be at some point.

At first look, Mode 6 may look obscure and intimidating most especially to amateur technicians. However, there are actually a lot of valuable diagnostic information for those who are willing to learn.

Here are some useful features of OBDII Mode 6:

Literally acts like a weatherman. Test results in Mode 6 can already tell you if there are some components that are performing below specified standards. This allows you to act quickly so as to avoid a Check Engine Light from coming on. This means technicians wouldn’t have to guess what’s messing up with the car.

A busy car doctor on-the-go. There are cases wherein scan tools won’t detect any problem in the car even if there appears to be an issue that needs attention. This happens when a scan tool thinks the issue is not big enough for a Check Engine Light on the dashboard to be turned on. Mode 6 will most of the time identify a type of problem like this and even show a failing test result.

A non-continuous monitor for PCM. Mode 6 allows technicians to easily find out if the powertrain control module (PCM) of a car has been tested and, whether or not, it has passed the exam.

Let’s take a look at some notable limitations of Mode 6:

A puzzle game that’s sometimes hard to solve. Mode 6 is often hard to interpret. Although it’s helpful for some who know how to decipher, its non-definitive nature may be complicated for most technicians.

Confusion may literally lead to failure on emission tests. Mode 6 varies from vehicle to vehicle. One vehicle may use current readings to carry out a test, while the other may utilize voltage readings. Incorrect interpretation of data may lead to undesirable results.



Car diagnostics have gone a long way as more and more options are being made available for technicians and regular drivers to utilize. It’s mainly up to the end users to think what’s suited for their skills and knowledge.

For those who are seriously considering learning more about the benefits of OBDII Mode 6, they’re highly advised to invest on a high-end scan tool that can decode information and see valuable information all at once.

While Mode 6 is capable of identifying components that are failing, there’s no better than using common sense in some cases.

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