Powertrain, shared range

P3427 Cylinder 4 Deactivation/Intake Valve Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P3427 is set when the cylinder 4 deactivation solenoid circuit has a path to ground. GM uses it on several 2019 V8s: the DFM engine L84, the AFM engine L86 and the LT4 of the Corvette. Once the low-side output is switched off, less than half an ohm toward ground fails the check; 20 of 25 samples, relay voltage at least 11 V, 425 rpm (L84) or 400 rpm (L86, LT4), Type B. In all three tables the criteria column names cylinder 1, an apparent copy slip. For the MDS-equipped Hemi from Chrysler, one STAR case documents an exhaust manifold shield that rubs the solenoid harness open; a bared wire touching metal there can end up as this kind of short. P3428 covers the opposite short, to battery voltage.

Likely causes

Control wire to the cylinder 4 solenoid rubbed through to ground, e.g. by a heat shield
Cylinder 4 solenoid shorted internally
Moisture or oil in the solenoid connector
Damaged driver in the engine control module

Symptoms

  • Check engine lamp after two drives
  • V4 or reduced mode never engages
  • Further circuit codes on other deactivating cylinders if the harness is damaged

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–900
Time0.5–4 h

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

Parts involved

cylinder deactivation solenoidwiring harnessecm

Related codes

P3425P3426P3428P3431P3419P3403

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.