P0697 Sensor Reference Voltage C Circuit/Open

P0697 indicates Sensor Reference Voltage C circuit is open or unavailable. Sensors sharing the C reference may lose their expected supply voltage.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

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 replace multiple sensors until the shared reference C circuit is measured and isolated branch by branch.

Symptoms of P0697

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0697

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Identify every sensor on reference circuit C, then compare reference voltage, signal voltages, grounds, freeze-frame data, and companion sensor codes.
Inspect open reference wiring, one shorted sensor loading the shared circuit, water intrusion, rubbed harness sections, and connector terminal damage.
Disconnect affected sensor branches according to service information to isolate whether the fault is a sensor, harness, or controller output.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.