Powertrain, shared range

P3440 Cylinder 5 Exhaust Valve Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P3440 closes the cylinder 5 block and stands for a high signal, usually a short to supply voltage, in the circuit of a separate exhaust valve actuator. No manufacturer documents this code publicly. The code only makes sense on an engine with a separate exhaust actuator; a Ford patent, for example, checks via exhaust pressure whether an exhaust valve still opens after deactivation. Current production systems that deactivate cylinder 5 drive both valves from one solenoid, and GM reports a short to power there as P3436, checked with the driver on and a 0.5 ohm limit. If a dedicated exhaust channel did short high, the computer would stop using deactivation and light the lamp. Compare P3437, P3438 and P3439.

Likely causes

Exhaust actuator control wire shorted to voltage
Shorted actuator coil
Engine control module output stage fault

Symptoms

  • Check engine lamp on
  • 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

P3437P3438P3439P3436P3400

References: law.cornell.edu, gsi.ext.gm.com, patents.google.com.