P2350 Cylinder 9 Pressure Variation High

P2350 is the opposite of P234F: the cylinder 9 pressure signal swings more than plausible, with peaks or steps that do not fit the engine's operating state. No manufacturer publishes the code for cylinder 9. The analogue in Saab's 9-5 diesel workshop data is P039D, labelled as excessive pressure variation for cylinder 1, set as soon as the signal is outside its window for over 0.2 s and treated as a signal performance fault of Type B. A noisy signal comes mostly from the electrical side – interference on an unshielded or chafed signal wire, poor ground, failing sensor electronics. Less often the combustion itself is uneven, for instance through an injector that dribbles after closing. CARB requires such rationality checks of input sensors. Drivers rarely notice anything beyond the MIL.

Likely causes

Symptoms

• Check engine light on
• Usually no noticeable symptoms

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: saabwisonline.com, law.cornell.edu.