Powertrain, shared range

P3457 Cylinder 8 Deactivation/Intake Valve Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Cylinder 8 is not among the cylinders that classic Active Fuel Management or Chrysler's MDS shut off (both use 1, 4, 6 and 7), so P3457 is documented only for newer designs. GM's 2019 tables list it for the L84 with Dynamic Fuel Management, which can deactivate every cylinder: more than 200 kohm with the low-side driver off, 20 of 25 samples every 250 ms from 425 rpm, Type B. GM's AFM/DFM information bulletin adds that the LTA and LT2 engines deactivate cylinders 2, 3, 5 and 8. GM also notes that some controllers store P3459 together with an open. P3458 is the function code for cylinder 8, P3459 and P3460 the short-circuit codes.

Likely causes

Wire to the cylinder 8 solenoid broken or chafed in the lifter valley harness
Open winding in the cylinder 8 solenoid
Poor contact at the solenoid connector
Engine control module output stage faulty

Symptoms

  • Check engine lamp on
  • Dynamic cylinder deactivation inhibited
  • P3459 may be stored alongside on some GM controllers

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

P3458P3459P3460P3461P3449P3400P3497

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