P0697

Sensor Reference Voltage C Circuit/Open

Sensor reference voltage (ECM) Generic OBD-II High

What it means

P0697 means the ECM detected an open (or out-of-range) condition on its third 5-volt reference circuit, "C." That regulated reference feeds several engine sensors, so when it's lost, multiple sensors read wrong at once — which can make the engine run poorly, drop into limp mode, or set a cluster of related codes.

High

Can I keep driving? Drive with caution — losing a shared 5-volt reference can throw off several sensors at once, causing poor running, limp mode, or stalling; get it diagnosed promptly.

Real-world scan data

Seen in

552

scans in the past year

Found in

0.1%

of scans

0.2%

of scans that found faults

Appears alongside · share of P0697 scans

P0641in 46.2% of scans

P0651in 30.2% of scans

P0193in 27.0% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on, often with several sensor codes set at once
Reduced power or limp mode
Rough idle, hesitation, or surging
Possible stalling or hard starting

Common causes

Most likely first

Open, or a short to ground or power, in the 5-volt reference C wiringLikely
A shorted sensor pulling the shared reference circuit downCommon
Corroded or loose connector on the reference circuitCommon
Faulty ECM/PCM 5-volt reference supplyLess often

How to diagnose & fix

Work through it in order

Scan for all stored codes — the sensors sharing reference C help pinpoint the circuit.
Inspect the reference-C wiring and connectors for opens, shorts, and corrosion.
With the key on, measure the reference voltage (should be about 5V) at the affected sensor connectors.
Unplug sensors on that circuit one at a time to find one shorting the reference down.
Only after wiring and sensors check out, consider a faulty ECM/PCM. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0697?+

Not really — the reference voltage feeds multiple sensors, so the engine can run poorly, drop into limp mode, or stall. Have it diagnosed before extended driving.

Can I just clear P0697?+

It returns quickly because the reference circuit is still faulty. Clearing won't restore the sensors that depend on it.

Read & clear P0697 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

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✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX