P0340 — Camshaft Position Sensor A Circuit
High SeverityAt a Glance
What It Means
The camshaft position sensor (CMP) circuit on Bank 1 is not providing a valid signal.
System
Engine — Position Sensing
Can I Drive?
Not recommended — risk of further damage.
Severity
High
Symptoms
- Check Engine Light illuminated
- Hard starting or no-start condition
- Rough running
- Engine may default to batch-fire injection mode
Common Causes
How We Diagnose P0340
Scan & Verify
Confirm P0340 and check for related codes that may share a root cause.
Live Data Review
Pull real-time sensor data to isolate whether the fault is electrical, mechanical, or software-related.
Component Test
Perform targeted tests on the specific circuit or component flagged by the code.
Root Cause Repair
Repair or replace only what is confirmed faulty — no parts-swapping guesswork.
Verify & Clear
Clear the code, perform a drive cycle, and confirm the monitor passes before returning the vehicle.
Related Services
Frequently Asked
Will code P0340 clear itself?
OBD-II codes do not clear themselves. The underlying fault must be repaired and the monitor must pass during a drive cycle before the light extinguishes.
Can I pass an Arizona emissions test with P0340 active?
No. Any active check engine light is an automatic emissions test failure in Arizona. The code must be resolved and the relevant monitor must complete before testing.
How long does a diagnostic take?
Most diagnostic appointments at Apex take 45–90 minutes. Complex electrical faults may require additional time for circuit testing.