Powertrain, shared range

P3455 Cylinder 7 Exhaust Valve Control Circuit Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

P3455 points to a ground fault on the line that would drive an exhaust-only actuator on cylinder 7. No manufacturer documents this code publicly. On GM V8 engines, AFM and DFM alike, a single lifter oil solenoid serves intake and exhaust of each cylinder, so a grounded line there sets the intake-side code P3451: the low-side driver is switched off, the output reads under 0.5 ohm to ground, and 20 of 25 checks taken every 250 ms must fail (Type B). On FCA's Hemi, MDS wiring rubbed through by the heat shield behind the driver-side head, next to cylinder 7, shows up as P3449. With its control line grounded, the actuator could switch on uncommanded, so the cylinder may lose its valve motion while fuel still flows. P3453 is the open, P3456 the short to power.

Likely causes

Actuator wire chafed through against the cylinder head or a heat shield

Actuator coil shorted to its housing

Output stage in the engine control module damaged

Symptoms

Check engine lamp on
Cylinder deactivation locked out
Rough running or misfire on cylinder 7 if the actuator pulls in unbidden

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

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