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.
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.
Related codes
Often seen with P0343
Read & clear P0343 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX