Powertrain, generic (extended)

P2342 Cylinder 7 Above Knock/Combustion Vibration Sensor Threshold

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2342 applies only to engines with seven or more cylinders, in practice V8s and larger. It says the vibration picked up by the knock sensor during cylinder 7's combustion window has exceeded the threshold. On a V8 each bank usually has its own sensor, so the module has to combine sensor choice and crank angle to blame the right cylinder; noise from a loose bracket or the valve train in that window can mimic knock. Saab's GM-based tables therefore run a separate abnormal-noise check between 2,000 and 8,500 rpm to spot a sensor that is not properly bolted. No manufacturer was found that publishes P2342; GM and Saab report single-cylinder knock as P0324. If knock is real, cylinder 7 needs a look at deposits, plug, injector and compression before damage occurs.

Likely causes

Loose bracket, heat shield or valve train noise in cylinder 7's window
Deposits or hot spots in cylinder 7
Knock sensor of that bank loose or wrongly torqued
Low-octane fuel (usually affects several cylinders)

Symptoms

  • Check engine light on
  • Possibly audible knocking under load
  • Less power from retarded ignition

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–4,000
Time0.5–8 h

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

Parts involved

knock sensorcylinder 7

Related codes

P2341P2343P0324P0330P0332P0307

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