The 2019 Mercedes-Benz C-Class triggering P0340 indicates a camshaft position sensor circuit malfunction on bank 1. This sensor provides critical timing information the ECM needs for fuel injection and ignition control.
Understanding P0340
P0340 sets when the ECM detects no signal or an irrational signal from the bank 1 camshaft position sensor. This can result from sensor failure, wiring issues, or mechanical problems affecting sensor readings.
C-Class Engine Options
The 2019 C-Class offers various engines including 2.0-liter turbo four-cylinder (M264) and AMG variants with different configurations. Bank 1 contains cylinder 1—for inline engines, this is the entire engine. Sensor location varies by engine.
Sensor Failure Symptoms
Beyond the check engine light, you may experience hard starting, rough idle, stalling, or reduced power. The ECM may enter a backup mode using crankshaft position data alone, but performance suffers.
Sensor Testing
Mercedes camshaft sensors typically use Hall effect technology. Test the sensor by checking reference voltage, ground, and signal output while cranking. Compare readings to specifications—erratic or absent signals indicate failure.
Wiring Inspection
The sensor connector and wiring can develop problems from heat, vibration, or moisture. Inspect for corrosion, damaged pins, or loose connections. Check wiring for chafing or breaks along the routing.
Repair Costs
Camshaft sensor replacement costs $200-450 at Mercedes dealers. Wiring repair runs $150-400 depending on damage extent. If timing chain issues are discovered, repairs can exceed $3,000.