P0343

Camshaft Position Sensor A Circuit High Bank 1 or Single Sensor

Cam / crank timing Generic OBD-II High

What it means

P0343 means the camshaft position sensor's signal to the engine computer is reading persistently high (out of range). The ECM uses cam position to time fuel injection and spark, so a bad signal can cause hard starting, stalling, misfires and reduced power — and in some cases the engine may not start at all.

High

Can I keep driving? Risky — the ECM relies on cam position for spark and injection, so hard starting, stalling or a no-start can strike without warning; fix it before relying on the car.

Real-world scan data

Seen in

345

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

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
Hard starting or intermittent no-start
Stalling or rough idle
Misfire or hesitation
Reduced engine power

Common causes

Most likely first

Faulty camshaft position sensorLikely
Wiring shorted to voltage or damaged in the sensor circuit (a high signal often means a short to power)Common
Poor or corroded connector at the sensorCommon
Metal debris on the sensor tip or a damaged reluctor ringLess often
Failed ECM (rare)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and check for related cam/crank codes (P0340–P0344) to see when the fault sets.
Inspect the sensor connector and wiring for shorts to power, chafing or corrosion.
Check the sensor tip and air gap for metal debris; inspect the reluctor/tone ring.
Replace the camshaft position sensor if the signal stays out of range.
Confirm crank/cam correlation; consider the ECM only after wiring and sensor test good.

FAQ

Quick answers

Is it safe to drive with P0343?+

Not reliably. A cam-signal fault can cause stalling or a sudden no-start, which is dangerous in traffic. Have it diagnosed before longer trips.

Can I just clear P0343?+

You can, but it will return as soon as the ECM sees the bad cam signal again. The sensor or its wiring needs to be repaired to keep it away.

Read & clear P0343 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