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P0340 Fault Code on Vauxhall Vectra: Camshaft Sensor Issue Due to Oil Contamination?

Model: Vauxhall Vectra Fault Code: P0340 Posted: 2015-07-27 07:28

New user here with a Vauxhall Vectra experiencing intermittent misfiring and rough idling. The OBD2 diagnostic code displayed is P0340 — Powertrain - Camshaft Sensor "A" Circuit (Bank 1 or Single Sensor). I've been advised that oil contamination may be blocking the camshaft oil passage, leading to sensor malfunction and engine misfires. While many online forums suggest checking wiring or replacing the sensor itself, this oil-related cause is rarely discussed. Given that my vehicle exhibits symptoms only when cold and resolves after warming up — with a noticeable rich fuel mixture and loss of power — I suspect an issue related to the oil path to the camshaft. Could contamination in the engine oil be obstructing the oil passage to the camshaft, causing intermittent sensor signal failure? Is this a known issue on Vauxhall Vectra models, particularly older units with high mileage or poor oil maintenance?

Related fault codes
P0340
Comments (3)
Anonymous 2015-07-29 20:13

I'm experiencing the same P0340 code. The problem only appears when the engine is cold. After warming up and restarting, the warning light disappears. While the lights are on, the engine runs rich, smells smoky, and loses power — similar to limp mode. I haven't opened the hood yet, but my suspicion points toward an oil sensor or port issue. The code clears once the engine warms up. Chad

Anonymous 2015-07-29 20:14

I should have clarified — my vehicle is a 2006 Vauxhall Vectra, not a Honda CRV. My mistake in typing that earlier.

Anonymous 2015-07-29 20:56

Chad, thank you for the clarification! This makes it much more relevant to the Vauxhall Vectra community and helps others with similar models find accurate troubleshooting guidance.