P0343 means Camshaft Position Sensor A Circuit High (Bank 1 or Single Sensor). The camshaft position sensor A signal voltage is higher than expected, often from an open circuit or lost ground. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0343 means
The engine computer uses the crankshaft position sensor to know engine speed and piston position, and the camshaft sensors to know which stroke each cylinder is on. On engines with variable valve timing, oil-driven cam phasers rotate the camshafts relative to the crankshaft under the control of solenoids. Timing codes come from a sensor that cannot be read, or from a measured cam angle that does not match the commanded one, so oil level and condition, sensor signals and mechanical timing all need checking.
P0343 symptoms
- Hard starting or long cranking
- Stalling
- Rough running
- Check engine light
Common causes of P0343
- Open ground or signal circuit
- Unplugged or corroded connector
- Failed sensor
How to diagnose P0343
- Check the sensor connector and wiring
- Check reference voltage and ground at the sensor
- Compare cam and crank signals with a scope or scan tool
- Check timing if the signal is present but out of place
Can you drive with P0343?
Use caution; the engine may stall or fail to restart.
P0343 tips
Check that the connector is fully latched after any timing cover or valve cover work.
Will P0343 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0343 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0340 | Camshaft Position Sensor A Circuit (Bank 1 or Single Sensor) |
| P0341 | Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or Single Sensor) |
| P0342 | Camshaft Position Sensor A Circuit Low (Bank 1 or Single Sensor) |
Guides that help
When it is more than a sensor
If a stretched chain has already jumped time and damaged valves, or low oil pressure has worn the engine, a repair can cost more than a replacement; see engine replacement cost and compare engines by code on our engines page.
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