P2340 Cylinder 5 Above Knock/Combustion Vibration Sensor Threshold

P2340 reports knock above threshold for cylinder 5, so it can only occur on engines with at least five cylinders – inline-five, six-cylinder, V8 or larger. The principle matches the rest of the series: the module evaluates the knock sensor signal in the crank-angle window of each combustion and retards spark individually when one cylinder knocks. No manufacturer was found that documents P2340 publicly; the Stellantis bulletin for P2336–P2339 concerns a four-cylinder engine and therefore stops at cylinder 4. GM and Saab detect the same condition but store P0324 (excessive knock on a single cylinder for more than 8 s). Causes are usually local to cylinder 5: deposits, a lean injector, a wrong plug or internal damage; poor fuel would affect several cylinders.

Likely causes

Symptoms

• Check engine light on
• Pinging or knocking under load
• Less power, higher consumption

Repair estimate

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

Parts involved

Related codes

References: saabwisonline.com, en.wikipedia.org, law.cornell.edu.