P06BC: A cylinder4 glow performance fault is not just an open-circuit result

P06BC concerns the cylinder 4 glow-plug range/performance assessment. Ford places this resistance check after the open, short-to-battery and short-to-ground checks. Keeping those stages separate prevents a resistance-performance code from being treated as merely another name for an open glow plug.

Heating mode supplies the measurement context

The documented operating mode is glow-plug heating, with approximately three seconds to register a malfunction. A resistance observation from a cold disconnected part does not automatically recreate that controller assessment.

The panel includes a resistance above 2 ohms as its individual-circuit criterion, but the associated threshold caption is labeled short to battery. This inconsistency remains a review limitation. The article does not silently reinterpret the caption or prescribe an unconditional ohmmeter limit.

Preserve the diagnostic progression

Record whether cylinder 4’s basic electrical checks were completed, whether heating was requested and which performance result was stored. A circuit that avoids an open classification may still be unsuitable under a resistance assessment; those findings answer different questions.

The code identifies one channel within a shared monitor family. It does not by itself localize resistance to the plug rather than its connections, harness or driver. Vehicle-specific electrical information is needed to resolve the actual fault path and applicable limit before choosing a repair, rather than replacing the cylinder 4 glow plug from the code alone.

Source and applicability

Ford 2023–2024 diesel OBD summary, August 25, 2023 revision; only the described monitor examples. Confirm the engine and calibration before applying values. The monitor explanation does not identify a failed part or replace the applicable service procedure. Ford PDF, page 116.