What causes a P0671 code?

P0671 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a P0671 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0671 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

OBD-II

P0671

Cylinder 1 Glow Plug Circuit Malfunction

What it means

The Engine Control Module has detected a voltage or resistance deviation in the heater circuit for cylinder number one's glow plug.