P0340: Camshaft Position Sensor 'A' Circuit Malfunction (Bank 1)
The ECM uses the Camshaft Position Sensor (CMP) to determine which cylinder is on its compression stroke for sequential fuel injection and ignition timing. P0340 indicates no pulse signal is received from the sensor during cranking.
Driveability & Safety Advisory
Vehicle may experience long crank, hard start, or intermittent stalling. Drive directly to repair.
Official Manufacturer TSB Advisories
Factory Condition: Official factory recall: Camshaft and crankshaft position sensors fail thermally when engine gets hot.
Physical Component Location & Service Access
Mounted in the cylinder head near the end of the intake camshaft.
Electrical Specifications & Live PID Benchmarks
Scan Tool Live Data Targets
Digital Multimeter (DMM) Specs
Documented Model-Specific Case Studies
Root Cause: Thermal breakdown of CMP sensor.
Verified Fix: Replace sensor with OEM Hitachi.
Technician Inspection & Testing Workflow
Check sensor connector for engine oil intrusion.
Verify 12V and ground with DMM.
Replace sensor with OEM component.
Cost Breakdown
Tools & Parts Matrix
Diagnostic Questions & Answers
Why does my car take so long to start when P0340 is active?
Without a camshaft signal, the ECM does not know which cylinder is firing. It has to crank repeatedly and guess timing based on crankshaft acceleration.