Cylinder Glow Plug Circuit Faults (12 codes)

What these codes mean

P0671 through P0682 identify glow-plug circuit faults for cylinders 1 through 12 respectively. The member list preserves every exact code and cylinder. A circuit result does not by itself identify a failed heating element, establish the engine layout or locate the plug.

Confirm the full manufacturer description, reporting controller and engine before following a cylinder diagram. The number does not establish a rear position, a particular bank, restricted access, plug material or installed cylinder count from a generic reader alone. If the description appears inconsistent with the vehicle, resolve the full scan and service-information match before buying parts. Do not assume that the reader must be wrong or that a donor controller is the cause.

The covered Ford 2023–2024 diesel summary lists P0671–P0678 under an open-load monitor while the plugs are in heating mode, with cylinders 7 and 8 restricted to its V8 application. The February 2014 Jetta/GLI CJAA table instead describes P0671–P0674 as open or short-to-ground circuit results. These are examples of monitor scope; their current limits and other criteria are not universal test specifications or evidence that every higher-numbered circuit is fitted.

Save the full scan, status, warnings and starting history. More than one cylinder code can justify investigating shared paths, but it does not prove one bad harness, module or fuse or rule out individual plug faults. Identify the actual supply, return, connections and controller outputs, then have the prescribed tests distinguish the circuit from its load. A resistance outlier, a normal indicator or a plug that heats on an improvised bench test does not independently settle the diagnosis.

Do not apply battery power directly to an unidentified glow plug, probe an energized terminal or remove a plug to test a guess. Use the specified isolation, compatible test equipment and exact engine removal procedure. Plug access, permitted removal conditions, extraction risk and whether any other plugs should be replaced are separate decisions after the fault is established. Cylinder number and common age do not justify a whole-set recommendation or a repair price.

Verify the confirmed repair using the monitor conditions required for the installed system. Glow operation can continue after starting; do not prescribe an overnight start or a road trip for every application. Judge urgency from actual starting reliability, warnings and vehicle guidance. A normal warm engine or one stored cylinder code is not a driving-safety or no-damage guarantee.