OBD-II code · Powertrain (generic)
P0697 Sensor Reference Voltage C Circuit Open
The 5-volt sensor reference rail C is open — the module supplies no voltage on this circuit. Every sensor powered from reference C loses its supply and reads invalid, so the ECU substitutes default values and may limit engine operation. Causes: a broken reference wire, a disconnected connector, or an internal open in the module's voltage regulator for rail C.
Is it safe to drive with P0697?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in shared reference rail
- Less likelyPin pushed back out of connector body
- Less likelyCracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- Parts involved
- Sensor Reference Voltage C
Related codes
- P0651Sensor Reference Voltage B Circuit Open
- P06A3Sensor Reference Voltage D Circuit Open
- P06D2Sensor Reference Voltage E Circuit Open
- P06D6Sensor Reference Voltage F Circuit Open
- P0694Cooling Fan 2 Control Circuit High
- P0695Fan 3 Control Circuit Low
- P0696Fan 3 Control Circuit High
- P0698Sensor Reference Voltage C Circuit Low
- P0699Sensor Reference Voltage C Circuit High
- P069ACylinder 9 Glow Plug Control Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.