From time to time you may encounter a problem with your parked regen light flashing. You will see this symbol on your dashboard.  

   

This light only comes on when the truck is requesting a parked regen. Every truck manufacturer designs this feature to appear when the soot level in the DPF filter reaches a certain level. When your truck is requesting a parked regen it means that the passive regen process your truck already went through was not enough to burn the soot in your DPF filter.  

Note: If you keep driving your truck without doing a parked regen your engine power and speed will be limited. 

 Use your onboard computer to check the fault codes.  

 

You will see one of these codes: 
MID 128 PPID 328 FMI 7 
MID 128 PPID 329 FMI 7 
SA 0 SPN 3471 FMI 7 
SA 0 SPN 5443 FMI 7 

Note: FMI 7 – Shut-off valve, the system does not react in the right way. The wrong software. 

It is more than likely that the problem could be the 7th injector is stuck closed. 

What you need to do is remove the 7th injector from your truck according to the manual: unscrew 2 bolts and disconnect the fuel line. Then look at the nozzle. If it is dirty or clogged, you found the issue.  

There are 2 ways to proceed from this point: 

1 –The cheap way (which may not help) is to try to clean it with carb/brake cleaner and toothbrush ( you should understand that you do this at your own risk and there is no guarantee that it will help.) 

2 – The preferred way - Exchange the part with a new one:

 

After you install the 7th injector you need to start regen process manually using truck`s onboard computer. 

It takes approximately 30-60+ minutes and will continue until the soot level has reached ‘low’ or ‘0%.’ Some trucks will let you monitor your soot level via a gauge on the dashboard. 

After the process concludes, you should be all set!! Have a good ride!