Powertrain, generic (extended)

P2BFC Exhaust Flow Control Valve B Position Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2BFC covers a general fault in the feedback path that tells the engine computer where exhaust flap B is. It applies only to systems with a second position-monitored flap, such as one per tailpipe, so on single-flap vehicles it cannot occur. No manufacturer documents P2BFC in public material. Ford defines valve B as its bank 2 flap and reads its state through the smart driver's PWM line; GM's 23OBDG07 tables supervise the PWM feedback of two exhaust valves, but under GM-specific codes with duty cycle limits of 2 and 98 percent over 4 seconds. CARB requires circuit monitoring for such inputs. In practice, compare the B side with the A side: if only B fails, look at its connector and wiring first, since the actuators are usually identical.

Likely causes

Flap B connector loose, wet or corroded
Feedback wire to flap B broken or heat-damaged
Position sensing in actuator B failed

Symptoms

  • Check engine light on
  • Exhaust mode selection limited or unavailable

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–900
Time0.5–2.5 h

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

Parts involved

exhaust flow control valve bwiring harnessecm

Related codes

P2BFDP2BFEP2BFFP2BF4P2BF8P2D12

References: law.cornell.edu, fordservicecontent.com, gsi.ext.gm.com.