P0682 Cylinder 12 Glow Plug Circuit

P0682 points to a cylinder 12 glow plug circuit fault. The cylinder 12 glow plug circuit is open, shorted, or outside expected current behavior.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Computer
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not skip cylinder identification checks on multi-bank engines before testing the cylinder 12 circuit.

Useful checks before replacing parts

Measure cylinder 12 glow plug resistance, command voltage, current draw, battery voltage, coolant temperature, and cold-start freeze-frame conditions.
Inspect cylinder 12 connector condition, harness heat damage, module output pin, terminal fit, corrosion, and shorts to ground or power.
Compare cylinder 12 measurements with other cylinders before replacing the glow plug, module, or harness branch.

Related OBD-II codes

These nearby computer entries can help compare wording and fault area. They may share the same verification status as the source database.