Powertrain, generic (extended)

P2B7B EVAP System Pressure Sensor/Switch C Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2B7B means sensor C delivers a signal that is electrically valid but implausible. Mercedes-AMG documents it as P2B7B26 on the GT63 S E Performance (2024–2026): the ME control unit sees the signal change too slowly, caused by interference on the line, and bulletin LI07.70-P-078293 cures it by twisting the sensor leads that run between the engine computer and the EVAP sensors. Audi's V6/V8 bulletin 2069531 lists P2B7B as pressure sensor 3 implausible, but explains that this entry is mislabelled and the test really belongs to P24D6 on sensor G950. VW's 2025–2026 Jetta and Taos set it together with the narrowed G400 orifice. CARB asks for two-sided rationality checks on inputs where feasible. Leak tests may be suspended meanwhile.

Likely causes

Interference on untwisted sensor wiring (Mercedes-AMG)
Sensor port or orifice too narrow or blocked
Fault entry assigned to the wrong sensor (Audi bulletin 2069531)
Pressure sensor C drifting or sluggish

Symptoms

  • Check engine light on, no driveability complaint
  • EVAP readiness monitor not completing
  • Code returns after clearing, often after a few drives

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–450
Time0.5–2.5 h

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

Parts involved

evap pressure sensor cwiring harnessecm

Related codes

P2B7AP2B7EP24D6P0451

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.