P0698

Sensor Reference Voltage C Circuit Low

Q: Is it safe to drive with P0698?

Not ideal — several sensors can lose their reference at once, causing poor running or limp mode. Diagnose it before driving far.

Q: Can I just clear P0698?

It comes straight back while the reference stays shorted; the shorted sensor or wire has to be found first.

Sensor reference voltage / ECM Generic OBD-II High

What it means

P0698 means the ECM's C sensor reference voltage — typically a 5-volt supply shared by several sensors — has dropped too low, usually from a short to ground. Because many sensors depend on that reference, this can trigger multiple sensor codes and make the engine run poorly, enter limp mode, or start hard until the short is found.

High

Can I keep driving? Be cautious — a low sensor reference can knock out several sensors at once, so the engine may run poorly, drop into limp mode, or be hard to start. Get it diagnosed promptly.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Appears alongside · share of P0698 scans

P0113in 65.2% of scans

P0118in 63.0% of scans

P0335in 63.0% 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 at once
Rough running, hesitation, or stalling
Reduced power or limp mode
Hard starting in some cases

Common causes

Most likely first

A sensor shorting the shared 5-volt reference circuitLikely
Damaged or corroded wiring or ground in the reference circuitCommon
Short to ground in the ECM harnessCommon
Faulty ECMLess often

How to diagnose & fix

Work through it in order

Scan and note every sensor that shares reference circuit C.
Inspect the reference wiring and grounds for shorts, damage, or corrosion.
Unplug the sensors on that reference one at a time; when the voltage recovers, the last-disconnected sensor is the short.
Repair the wiring or replace the shorted sensor.
If the circuit stays low with the sensors disconnected, suspect the ECM.

FAQ

Quick answers

Is it safe to drive with P0698?+

Not ideal — several sensors can lose their reference at once, causing poor running or limp mode. Diagnose it before driving far.

Can I just clear P0698?+

It comes straight back while the reference stays shorted; the shorted sensor or wire has to be found first.

Read & clear P0698 yourself

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

▶ Get it on Google Play

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