P0430 — Catalyst System Efficiency Below Threshold Bank 2
What it means: Catalyst System Efficiency Below Threshold Bank 2.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Inspect exhaust for oil residue
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Houston, TX
Closest first. Tell them P0430 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Houston, TX · (832) 377-0578
- 0.0 mi away — based in Houston, TX · (713) 219-9090
- 0.0 mi away — based in Houston, TX · (713) 671-9751
Seen on: Heavy Truck/Diesel
What P0430 means
Catalyst System Efficiency Below Threshold Bank 2. Common causes: Catalyst contaminated or damaged.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Catalyst contaminated or damaged
- Engine oil consumption
- coolant leak to exhaust
First moves (roadside)
- Inspect exhaust for oil residue
- check coolant level trend
FAQ
Catalyst System Efficiency Below Threshold Bank 2. Common causes: Catalyst contaminated or damaged.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Catalyst contaminated or damaged. Other possibilities include Engine oil consumption; coolant leak to exhaust.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P0430, or share the same subsystem.
- SCR Operator Inducement — Severe Derate Active (SPN 5246 FMI 0)
- Aftertreatment 1 Diesel Particulate Filter Differential Pressure - Data Valid But Above Normal Operating Range, Most Severe Level (DPF severely restricted / plugged) (SPN 3251 FMI 0)
- Aftertreatment 1 Diesel Exhaust Fluid Quality - Data Valid But Below Normal Operating Range, Most Severe Level (DEF quality/concentration incorrect) (SPN 4364 FMI 1)
- DPF Differential Pressure — Data Erratic (SPN 3251 FMI 2)
- DEF Dosing Unit — Not Responding Properly (SPN 3361 FMI 7)
- SCR Conversion Efficiency — Below Threshold (SPN 4364 FMI 18)
- DEF Quality — Out of Spec (SPN 4094 FMI 31)
- EGR Temperature — Too High (SPN 412 FMI 0)
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.