Powertrain, shared range

P3448 Cylinder 6 Exhaust Valve Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

If cylinder 6 had its own exhaust valve actuator, P3448 would report its control line shorted to battery voltage. No manufacturer documents this code publicly. A GM patent application on cylinder deactivation switches both sides through one shared hydraulic valve and only lets the exhaust valves go first, off and back on, so it shows no separate exhaust control either; GM's production V8s likewise put both lifters on one solenoid and publish only P3444 for a short to power on cylinder 6. That test, below 0.5 ohm to power with the driver switched on and 20 of 25 samples, is the reference for how such a fault would be judged. With the actuator unusable, deactivation is blocked. P3445 to P3447 are the sibling exhaust codes.

Likely causes

Exhaust actuator wire touching a supply line
Shorted turns in the exhaust actuator coil of cylinder 6
Engine control module output stage faulty

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

P3445P3446P3447P3444P3497

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