Powertrain, shared range

P3423 Cylinder 3 Exhaust Valve Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P3423 points to a grounded control wire at a dedicated cylinder 3 exhaust actuator. No manufacturer documents this code publicly, and NHTSA's 2025 look at GM's DFM engines shows why: each cylinder has just one lifter oil solenoid, and it feeds both lifters, intake and exhaust, so there is no separate exhaust output that could fail. For that same solenoid on cylinder 3, GM's L84 table flags a resistance to ground under half an ohm at rest and files it as P3419. The 2007 Displacement on Demand application likewise lists only one solenoid circuit for cylinder 3. Any design with its own exhaust output would fall under the CARB duty to detect shorts. Effect: warning lamp, cylinder 3 stays active.

Likely causes

Exhaust actuator wire of cylinder 3 shorted to engine ground
Actuator winding shorted to its housing
Faulty output stage in the control module

Symptoms

  • Check engine lamp on
  • No switch to reduced-cylinder operation

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

P3421P3422P3424P3419P3431P3415

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