Powertrain, shared range

P3486 Cylinder 11 Exhaust Valve Control Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P3486 flags a functional problem with the exhaust valve of cylinder 11: the circuit is healthy, but the valve does not reach the commanded state. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. With a twelve-cylinder engine the consequences of a valve that keeps opening are that the cylinder pumps cold air through the exhaust and the converter cools, the issue Bentley avoids on its W12 by alternating banks. A Ford patent shows how such a leaking exhaust valve can be spotted from exhaust pressure. The reverse fault, a valve that stays shut, compresses trapped gas when the cylinder returns. As none of the known V12 or W12 systems switches valves individually, there is no documented user. P3485, P3487 and P3488 are the electrical faults.

Likely causes

Exhaust switching element of cylinder 11 jammed
Oil supply inadequate for exhaust switching
Exhaust actuator slow to respond

Symptoms

  • Check engine lamp on
  • Knock when cylinder 11 reactivates
  • Misfire on cylinder 11 (P0311)

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–3,500
Time0–12 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

cylinder deactivation solenoidlifterengine oil

Related codes

P3485P3487P3488P3482P0311

References: law.cornell.edu, patents.google.com, bentleymedia.com, mobilityengineeringtech.com.