Powertrain, shared range

P3454 Cylinder 7 Exhaust Valve Control Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P3454 covers an exhaust valve on cylinder 7 that does not switch as commanded, with no electrical fault on its control circuit. No manufacturer documents this code publicly. GM's own cylinder 7 check P318F on the 2019 L84 shows why the exhaust side matters: if the exhaust valve fails to open and release the burned gas, the trapped charge is compressed again, cylinder pressure climbs and the intake mechanism can be damaged on reactivation, so the ECM reacts at once (crankshaft jerk test, 66 of 100 samples, Type B). A Ford patent tackles the reverse problem, an exhaust valve still opening after deactivation, spotted through exhaust pressure. P3453, P3455 and P3456 are the electrical codes.

Likely causes

Exhaust lifter of cylinder 7 stuck in the unlocked state
Oil pressure or oil quality inadequate for switching
Exhaust control valve slow or sticking

Symptoms

  • Check engine lamp on
  • Hard knock or jolt when cylinder 7 is reactivated
  • Possible misfire on cylinder 7 (P0307)

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–3,500
Time0–12 h

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

Parts involved

cylinder deactivation solenoidlifterengine oil

Related codes

P3453P3455P3456P3450P349EP0307

References: law.cornell.edu, gsi.ext.gm.com, patents.google.com.