Decode the Problems Before They Cost You
Diesel engines are tough, but when something goes wrong, they let you know with diagnostic trouble codes (DTCs). Here are five of the most common codes every diesel operator should understand.
1. P2002 – DPF Efficiency Below Threshold
Indicates your filter isn’t cleaning soot effectively. Often caused by a clogged DPF or failed regen.
2. P2463 – DPF Soot Accumulation
Your truck is telling you there's too much soot. A forced regen is typically required.
3. P203F – DEF Fluid Level Low
Triggered when your Diesel Exhaust Fluid is running low. Refill immediately to avoid power loss.
4. P0420 – Catalyst System Efficiency Below Threshold
Means your catalytic converter isn’t performing efficiently. Often tied to DPF or DOC issues.
5. U0100 – Lost Communication With ECM
A scary one. Indicates your ECM isn’t talking to other modules. Check wiring or battery health.
Bonus Tip: With a handheld diagnostic tool from OTR Garage Tools, you can identify and clear these codes yourself—saving time, money, and stress.