Powertrain, shared range

P3436 Cylinder 5 Deactivation/Intake Valve Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P3436 is the short-to-power code for the cylinder 5 deactivation valve. Publicly it is documented by GM for the L84 V8 (2019), where Dynamic Fuel Management uses a dedicated valve lifter oil solenoid for each of the eight cylinders. The engine computer checks the line while its low-side driver is on; an impedance below 0.5 ohm toward supply voltage counts as a fault, confirmed by 20 of 25 samples at 250 ms, with at least 11 V and 425 rpm. As a Type B code it lights the lamp after two consecutive trips. Because the solenoid then cannot be switched in a controlled way, cylinder 5 is excluded from deactivation. Siblings: P3433 open, P3435 short to ground, P3434 function.

Likely causes

Control wire touching a voltage supply
Shorted coil in the cylinder 5 solenoid
Engine control module output stage defect

Symptoms

  • Check engine lamp after two trips
  • Dynamic Fuel Management disabled

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

P3433P3434P3435P3440P3400

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