P0340 Subaru Forester
Camshaft Position Sensor Circuit Malfunction (Bank 1) · Powertrain Code · High · Repair: Moderate
What is P0340?
The camshaft position sensor on bank 1 is not providing a valid signal. Engine may not start or run poorly.
When the Subaru Forester triggers code P0340 (camshaft position sensor circuit malfunction (bank 1)), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Subaru Forester.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Subaru Forester.
Common Causes on Subaru Forester
- Failed camshaft position sensor
- CMP sensor wiring open or shorted
- Timing chain or belt issue causing incorrect cam signal
- Oil contamination on CMP sensor from cam seal leak
Symptoms
- Check Engine Light on
- Hard starting or extended cranking
- Rough idle
- Possible stalling
- Reduced power
Notes for Subaru Forester
FB-series engines use timing chains; older EJ engines use timing belts that require scheduled replacement at 105k miles.