Powertrain, shared range

P3452 Cylinder 7 Deactivation/Intake Valve Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Unlike the open and ground-short checks, GM can only detect P3452 while the cylinder 7 solenoid driver is switched on, because a short to supply voltage shows up as an output that will not pull low when it should. The 2019 tables for the L84, L86 and LT4 set the limit at 0.5 ohm to controller power and need 20 errors out of 25 samples, Type B. The check therefore depends on the ECM actually commanding deactivation; on GM's DFM engines that only happens with coolant above 40 °C, more than 20 s after start and above 13 km/h, according to NHTSA. Typical causes are a harness pressed against a feed wire or a solenoid with shorted windings. P3449 and P3451 are the other circuit codes for cylinder 7.

Likely causes

Cylinder 7 control wire shorted to a voltage feed
Low-resistance coil in the cylinder 7 solenoid
Engine control module driver defective

Symptoms

  • Check engine lamp on, often only after longer warm drives
  • Cylinder deactivation unavailable

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

P3449P3450P3451P3456P3400

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