P0343: Camshaft Position Sensor A Circuit High Bank 1 or Single Sensor
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes with care - starting may become unreliable.
Symptoms
- Longer cranking before starting
- Rough running
- Occasional stall
Likely causes, most common first
- Camshaft position sensor signal shorted to voltage
- Failed sensor
- Wiring damaged by heat
- Timing chain wear affecting the signal pattern
Read P0343 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0343 reports the bank 1 camshaft position signal stuck high. The cam sensor tells the computer which stroke each cylinder is on, which is what allows sequential fuel injection and, on many engines, a quick start.
Most cars will still start and run without a trusted cam signal by falling back to a slower strategy, which is why the complaint is usually longer cranking rather than a no-start. If a new sensor does not settle it, check the sensor's target on the camshaft: a worn or slipped timing component changes the signal pattern in a way no sensor can correct.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Cars that report P0343 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0343?
Yes with care - starting may become unreliable.
How much does it cost to fix P0343?
Typical US repair costs range from $80 for the simplest fix (camshaft position sensor) to $2,500 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0343. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.