Powertrain, shared range

P340D Deactivation/Exhaust Valve Control Circuit Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P340D is the bank 2 version of the exhaust-side group circuit: the engine computer sees an electrical fault on the line that is supposed to disable the exhaust valves of the bank without cylinder 1. No manufacturer documents this code publicly. Separate exhaust control matters because a cylinder can only act as a gas spring if its exhaust valves stay shut too; a Ford patent shows how an exhaust valve that keeps opening can be detected from exhaust pressure. On known engines, though, intake and exhaust are switched together per cylinder, as with GM's DFM. CARB rules call for monitoring of outputs like this one. Related: P340C for bank 1, P340B for the bank 2 intake side, P341D for the function check. Deactivation stays off.

Likely causes

Damaged wiring to the bank 2 exhaust deactivation actuator
Faulty coil in the bank 2 exhaust actuator
Output stage fault in the engine control module

Symptoms

  • Check engine lamp on
  • Engine no longer drops cylinders at light load

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

P340CP340BP341DP3497

References: law.cornell.edu, patents.google.com, static.nhtsa.gov.