What P0343 means
P means powertrain (engine and transmission). The 0 marks a generic code defined by SAE, so the same number means the same thing across makes. The third character, 3, places it in the ignition system or misfire subsystem; the last two digits identify the specific fault.
The camshaft position sensor tells the engine computer which stroke each cylinder is on, so it can time sequential injection and ignition. On engines with variable valve timing it also reports actual cam position. "A" and "B" identify which camshaft (commonly intake and exhaust) as defined by the manufacturer.
Bank 1 is the side of the engine that contains cylinder 1. Inline engines have only bank 1, so a bank 2 code on an inline engine usually indicates a manufacturer-specific use.
What “Circuit High” means here
"High" means the signal or control voltage rose above the maximum the module expects. On a three-wire sensor fed by a 5 V reference, typical causes are a signal wire shorted to the reference or to battery voltage, an open sensor ground, or a failed sensor.
What you may notice
Symptoms depend on the vehicle and on how the module responds to the fault. Any of these can accompany P0343:
- Long cranking or hard starting
- Rough running or hesitation
- Variable valve timing codes stored alongside
- Reduced power
Where to start diagnosing P0343
- Inspect the connector and harness at the sensor.
- Check engine oil level and condition; poor oil affects variable valve timing and can make cam signals look wrong.
- Watch for correlation codes between crank and cam, which can indicate timing chain or belt stretch.
- Inspect the sensor tip for debris.
Clear the code only after recording freeze frame data: it shows the engine speed, load and temperature at the moment the fault set, which is often the best clue to reproducing it.
Live data to watch
These standard OBD2 values relate to P0343. Support varies by vehicle; a value your car does not report will simply be missing.
| Value | What to look for |
|---|---|
| Engine RPM (PID 0x0C) | Starting and idle stability. |
| Variable valve timing data | Usually manufacturer-specific: desired vs actual cam angle. |
Related codes
Codes from the same camshaft position (CMP) sensor family. If several are stored together, the shared part — wiring, a common reference voltage, or the component itself — is the place to start.
| Code | Definition |
|---|---|
| P0340 | Camshaft Position Sensor A Circuit Malfunction (Bank 1) |
| P0341 | Camshaft Position Sensor A Circuit Range/Performance |
| P0342 | Camshaft Position Sensor "A" Circuit Low (Bank 1 or Single Sensor) |
| P0344 | Camshaft Position Sensor "A" Circuit Intermittent/Erratic (Bank 1 or Single Sensor) |
| P0345 | Camshaft Position Sensor "A" Circuit (Bank 2) |
| P0346 | Camshaft Position Sensor "A" Circuit Range/Performance (Bank 2) |
| P0347 | Camshaft Position Sensor "A" Circuit Low (Bank 2) |
| P0348 | Camshaft Position Sensor "A" Circuit High (Bank 2) |
Further reading
Frequently Asked Questions
What does P0343 mean?
P0343 is the generic SAE J2012 code for "Camshaft Position Sensor "A" Circuit High (Bank 1 or Single Sensor)". In plain terms, it means the engine computer has detected a "circuit high" fault on the camshaft position (CMP) sensor.
Can I keep driving with P0343?
Many engines still run on the crank signal alone, but starting and performance may suffer. Get it checked soon.
What should I check first for P0343?
Inspect the connector and harness at the sensor.
Definition source: SAE J2012 / ISO 15031-6 generic DTC definitions. This is the generic meaning that applies across makes; a manufacturer can define a code more narrowly or add its own sub-codes, so confirm against the service information for your vehicle before replacing parts. Written by the OBDAssistant engineering team — see our editorial policy.