P0698 Sensor Reference Voltage C Circuit Low

P0698 points to a low condition on Sensor Reference Voltage C circuit. The shared C reference supply is below the expected voltage range.

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 condemn the controller until each sensor and harness branch on reference C has been isolated.

Useful checks before replacing parts

Measure reference voltage C at the controller and affected sensors, then review companion sensor codes, freeze-frame data, and sensor ground integrity.
Inspect for short-to-ground faults, a shorted sensor on reference C, crushed harness sections, water intrusion, connector corrosion, and poor terminal fit.
Unplug sensors on the C reference circuit systematically to see whether voltage recovers and identifies the loaded 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.