Regen Light Still On After Regen? Here Are Possible Reasons!

Is your regen light still on after regen?

This is something that a few people observe with their vehicle even after a regen. When you have already conducted and completed a regen, the regen light is supposed to switch off, right?

So, why does it happen with other people that the light remains on even after this procedure has been finished? 

Find out exactly the cause of this issue and what you can do about it. Let’s get started.

regen light still on after regen

Regen Light Still On After Regen

We have heard of a few truck owners who complain about their regen light staying on after they have done a regen. But prior to this scenario, everything appeared to be just fine – no problems at all. 

However, it began with the check engine light turning on while driving. Then, there was a message that appeared after a few hours saying a parked regen is required immediately and that the engine is in derate. 

Although the driver did not at all notice the engine was in derate, the driver decided to pull over and conducted a regen. Then, they inspected their gauge for a filter and while it appeared to be fine, they still decided to check it anyway. After an hour or so, the regen process was completed. But then the message persisted, so it gave the driver some concerns about driving even with the message still on.

The fortunate thing was that the driver reached the destination without any issues – and that is even with the regen light on and the message never going away. This is why the driver decided to take the vehicle to a mechanic and have it inspected. 

The mechanic ran a diagnosis and looked for some error codes, yet the check engine light remained. They also did a forced regen, removed the filter housing, cleaned the filters, as well as the dozer injectors. Nevertheless, all of these did not do anything to turn the regen light off nor did it eliminate the message. 

As a result, they recommended taking the vehicle to a Volvo dealer for further inspection of the issue. This leaves a number of drivers wondering if there is something completely and seriously wrong with their vehicle, or if this is fairly normal. After all, despite the regen light and the message, things appeared to be working fine.

Now, a possible issue would be in your DPF filter. This is why we recommend checking for some staining on either side. If so, this means that there is a thermal failure occurring in your filter, or the filter is actually melting inside. One other driver with 410k miles on the truck was planning on replacing the filter.

Furthermore, many regen strategies come with an ECM monitor, and it does not declare a regen to be finalized until a specific temperature has been reached for a specific period. It only means that a certain component has not met the criteria required. But in most cases, another code is required to be logged in to report the regen failures. 

Most of the time, the light turns on only when your vehicle requests  parked DPF regen. This varies from one truck to another, depending on the manufacturer’s design. It can also sometimes show up when the DPF filter’s soot level has reached a particular level to ensure the truck’s proper operation. 

When you notice that your truck requires a so-called parked DPF regen, this means that there is a passive DPF regen completed by the truck, yet it does not suffice in burning soot in the DPF filter. 

However, it is for certain that when your vehicle is requiring a parked DPF regen, it really needs to be done. Otherwise, if you continue to drive without completing a parked DPF regen, then the vehicle will get into a derate mode. What this means is that you will have a limited speed and engine power, which can be an inconvenience for you.

Additional Points To Consider

It is also worth noting that an active DPF regen is one thing to keep in mind, which basically means that your vehicle performs this process in an automatic manner. It usually occurs once soot has reached a particular threshold and begins the process of burning this soot off. The engine also tends to run harder than normal when in the active mode.

There are numerous causes for a failure in the active regen as it depends on conditions required to be met for it to be completed. Yet, if for some reason, you failed to do a parked regen, this means that further issues are likely to occur. There may also be more derates to happen if you choose to drive anyway. This is why it is best to observe the problem as it occurs and do something about it by seeking professional assistance.

For the most part, it takes about 20 minutes to an hour or so to finish a parked DPF regen. It will keep on doing a regen until your soot level is at zero percent or lower than it used to. You may also be required to monitor the soot level gauge found on the dashboard.

It is also good to know the difference between a parked and a forced DPF regen. When it comes to a parked DPF regen, you begin the process by pushing the button on your dashboard. On the other hand, a forced DPF regen requires a diagnostic scan tool to be used, which will initiate the process. There is no need to perfectly meet conditions and the mechanics will initial a forced regen for you.  

The purpose of a forced DPF regen is to ensure the proper condition and function of the aftertreatment system. So, if you are able to do a forced DPF regen even without any issues or fault codes showing up, then your vehicle should be ready to go.

Final Thoughts

When the regen light is still on even after regen, it means that the process has not been completed yet. It is good to have a specialist to take a look at this issue for a definitive solution to the problem and make sure there are no further risks to your truck.

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