Isuzu NPR Exhaust System Warning Light and Symbols
The exhaust filter light that asks for a regeneration.
What the exhaust light means
The DPF traps soot from the diesel exhaust and burns it off during a regeneration. The exhaust light comes on when the filter is filling. If you also see a temperature or check engine light, the regen has been delayed and the truck may start cutting power to protect the filter.
Exhaust system (DPF)
The diesel particulate filter needs to regenerate. Drive at highway speed, or run a parked regen per the manual.
How to clear it
- Drive steadily at highway speed for 20 to 30 minutes to trigger an active regen
- Or run a parked (manual) regen using the switch, following the manual
- Keep DEF topped up and use the correct low-ash diesel oil
- Do not keep making short stop-start trips, which block the filter
When it needs a shop
If the light will not clear after a proper regen, or a check engine and power reduction appear, the filter may be too full for a normal regen. At that point it needs a forced service regen or cleaning at a shop before it damages the DPF.
Your questions answered
What does the exhaust system light on an Isuzu NPR mean?
The diesel particulate filter is full of soot and needs to regenerate. A steady highway drive or a parked regen usually clears it.
How do I run a regen on an Isuzu NPR?
Drive at highway speed for 20 to 30 minutes, or use the parked regen switch while stationary following the owner's manual. Do not interrupt it.
What if the DPF light will not go out?
If a normal regen fails and a check engine light or power loss appears, the filter needs a forced regen or cleaning at a shop.