P0266 — Cylinder 2 Contribution/Balance Fault
Seen on: Heavy Truck/Diesel
Cylinder 2 Contribution/Balance Fault. Common causes: Cylinder 2 not contributing equal power.
Your code rides along, so nearby mechanics see the fault before they quote you.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Cylinder 2 not contributing equal power
- Worn injector
- low compression
First moves (roadside)
- Cylinder balance test and compression check on cylinder 2
FAQ
Cylinder 2 Contribution/Balance Fault. Common causes: Cylinder 2 not contributing equal power.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Cylinder 2 not contributing equal power. Other possibilities include Worn injector; low compression.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
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.