P0286 Cylinder 9 Injector Circuit High

P0286 indicates a high injector circuit on cylinder 9. The injector 9 circuit is open, shorted to voltage, or above expected range.

Code status

Needs verification

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

System: Injector
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 assume injector 9 is mechanically failed until the high circuit is electrically isolated.

Useful checks before replacing parts

Check injector 9 signal voltage, feed supply, ground control, open circuits, short-to-voltage faults, and injector resistance.
Compare cylinder 9 balance, misfire, contribution, and injector command with nearby cylinders under similar load.
Inspect terminal fit, connector corrosion, harness heat damage, water intrusion, and controller driver behavior during loaded testing.

Related OBD-II codes

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