A car is one of the most convenient modes of transportation for the majority of the population.
This is why it is so important that we diagnose and check our engines for any faults or malfunctions. In the abstract below, you will get to know the relevant information regarding the engine regen of a car.
Can I Turn Off Engine Regen In Progress?
You can turn off the engine during regen without causing any harm to the DPF since the conditions enabling the regen will subside – stopping the regen when the engine is off. Keep the exhaust away from any combustible item when parking the vehicle to prevent them from catching fire.
An engine regen is when soot builds up in the Diesel Particulate Filter (DPF) of the vehicle so much that the vehicle no longer runs and has to be cleaned.
If this happens in the middle of the road, it would take around 40 minutes for the car to self-clean the soot, which could be problematic if you are in a hurry.
To prevent such a dilemma, you could force an engine regen to self clean the soot build up so that you don’t have to spend your valuable time on the road.
To perform an engine regen, you need to switch off your car while it’s halfway through active regen which would take around 45 minutes to an hour.
Normally, doing so would not do any harm to the DPF but it may fail to properly get rid of all the soot that had built up.
As you shut down the engine, the regeneration will stop because the conditions necessary to keep the regeneration going will be shut off.
This is called a parked regen and given the right conditions are met – this will properly get the DPF rid of any soot. However, while performing this you need to make sure that your vehicle is parked in an open area.
The exhaust will reach very high temperatures and if there are any flammable items nearby, they could result in a fire or if there are trees and grass it could lead to a large fire.
Therefore, make sure the area is either an open space or is well ventilated to allow a sufficient flow of air.
Can I turn off engine regen during DPF regeneration? Is it bad to stop a regen?
You can turn off engine regen during DPF regeneration but doing so does pose some risk to your engine in exchange of saving time for the regen process.
You can turn off your car engine to interrupt the process if you’re tight on time or else, interrupting the engine to stop the regen could be harmful as the filter may not be properly cleaned.
While stopping a regen, you can keep the filter clean from the soot build-up by burning the soot at a very high temperature that would cause the soot to burn to ashes and get expelled out of your vehicle.
Frequently stopping a regen is bad for your vehicle and can cause further problems to the DPF if the cleaning is not properly completed.
Turning off the engine to stop the regen also has some latent consequences that your vehicle has to face further down the road.
Your vehicle would usually resume its regeneration process after you have forcefully turned it off and in most cases, the regen will take even longer to complete.
Another noticeable fact is that if you stop the regen process more than twice, the soot level will not level down as much and thus you’ll have more frequent regens and have an overall lower MPG.
Interrupting the cycle also causes the overall temperature of the exhaust system to go up.
What happens if I stop a regen?
Below listed are the symptoms that occur when you stop a regen:
Ash build ups in the exhaust:
When the DPF burns away the soot build up, ash is created in the process that builds up in the DPF. These ash deposits cannot be burned away and removed from the system and can only be removed with a specialized DPF cleaning tool.
So as soon as you notice a poor vehicle performance and a back pressure from your exhaust due to the ash build ups. The more you stop the regen, the faster the ash will build up.
Engine shuts down:
The regeneration process causes the accumulated soot to burn up and get removed from the vehicle system.
However, if the regen does not start or get stopped midway then your vehicle will eventually end up in a derate and cause your engine to shut down.
DPF or Check Engine Lights gets turned on:
DPF lights or Check Engine Lights get lit up if there’s any issue in the engine. If you stop the regen way too many times, then the sensors will detect this anomaly and will cause the DPF lights or Check engine lights to light up.
How do you know if your truck is in regen? How do you know when regen is done?
When your vehicle is in regen, there are some visible giveaways that signal whether your vehicle is undergoing the regen process or whether the regen is
Lower fuel economy:
During regen, the fuel economy of your vehicle is affected and causes the mileage to decrease by 4 to 6 MPG.
While you’re driving, take notice of your fuel economy, if you notice it to be less than the 25 mile average – then your vehicle is undergoing regeneration.
Higher RPM at idle:
While the regeneration process is ongoing, the engine will have a higher RPM than usual.
This is best noticed when your vehicle is at idle, whether it be at the red light or the parking lot, you will notice that the RPM is around 750 whereas the RPM is around 500 when it is not in regen.
Notice the exhaust temperature and RPM:
When your vehicle is in regeneration, its temperature and RPM both will be high so that is a clear giveaway that your vehicle is in regen.
In order to recognize when the regen has completed, you need to monitor the temperature of the exhaust and RPM at idle, when the regen of your vehicle ends – both of them will come down to their normal levels which would signal the completion.
How long does regen in progress take?
A vehicle undergoes regeneration process whenever there is soot accumulation in the DPF, which makes it difficult for the vehicle to reach optimum performance.
Regen causes the soot build-ups to burn to ashes at high temperatures and get out of the vehicle system – which usually takes upto 40 minutes, during which the vehicle has to be pulled over and parked.
If there are no issues with your vehicle or the DPF, then this regeneration process would usually take between 30 to 60 minutes on average.
Another thing to note is the heat up time for the regen, if your vehicle is regenerating in a cold area, then it would take additional time to heat up for the regen.
Although there is an average time that the regen occurs for, the most important contributing factor that determines the time for regen is the soot level in the DPF. Until the system gets rid of all the soot build-ups in the filter, the regen will continue.
There are some trucks that show you the soot level on the dashboard which can give you an estimate of the time remaining.
Why is regen taking so long?
The greater the soot build-ups in the filter, the longer the regen will last because your vehicle is still trying to reduce the level of soot build-up in the DPF.
However, if you notice that your vehicle is undergoing DPF regen for more than an hour, then it means that your exhaust temperature is most likely not high enough to burn off the soot fast enough.
For a parked regen, your vehicle should take from 45 minutes to an hour at max, if you notice that the regen is still ongoing past the one hour mark then you need to contact a mechanic since there is an anomaly that has been delaying the regen from completion.
You can switch off the engine during regen without harming the DPF since the conditions for the regen will diminish, thereby stopping the regen when the engine is turned off. When parked, keep the exhaust away from any flammable items to avoid them from catching fire.
I am an automotive enthusiast and have been interested in cars since I was a little kid. I have worked in the automotive industry for many years and have extensive knowledge of vehicles and their engines. I am a father of two and I love spending time with my family.
Read more about the author here.