Camshaft Position Sensor for Alfa Romeo 156 159 Brera GT Spider 2.0 2.2 JTS

Use an OBD2 scanner to check for fault codes P0335 to P0338 (crankshaft) or P0340 to P0349 (camshaft). You can also test the sensor with a multimeter - inductive sensors should show resistance between 200 and 1,000 ohms, while Hall effect sensors require a live voltage test with the engine cranking. Erratic or absent RPM signal on a live data scanner is a strong indicator of sensor failure.

Yes. A faulty crankshaft position sensor in particular can cause the ECU to lose engine speed and position data entirely, which may trigger limp mode or prevent the engine from starting. A faulty camshaft sensor on variable valve timing engines can cause the VVT system to default to a fixed position, significantly reducing power and fuel economy.

In most cases no - aftermarket OEM replacement sensors are direct plug-in replacements that require no programming. However some vehicles, particularly late model European makes including BMW and Mercedes-Benz, may require a crankshaft adaptation reset using a dealer-level scan tool after replacement. Check your vehicle service information before replacing the sensor.

Symptoms include intermittent stalling, engine not starting, rough idle, misfires, and a Check Engine light with codes P0335-P0338. In severe cases the engine will crank but not start as the ECU cannot determine crank position for ignition timing.

Symptoms include poor performance, misfires, difficulty starting, rough idle, and fault codes P0340-P0343. Variable valve timing systems (VVT) will also be affected, causing sluggish response and increased fuel consumption.

If the sensor has failed completely the engine will not start or will stall and not restart. If it is intermittently failing, driving is dangerous - the engine can cut out without warning. Replace it immediately.

Not necessarily - replace whichever has failed based on fault codes and diagnosis. However, if your vehicle has high kilometres and one has failed, it is worth considering replacing both as they are similar in age and condition.