Powertrain, generic (extended)

P2A0B Manifold Absolute Pressure Sensor B Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2A0B means the MAP B signal stays inside its electrical range but does not fit the operating state. GM documents it for the Corvette's LT6 V8, where sensor B reads the bank-2 manifold pressure, with several checks: before the engine turns, the raw reading has to agree with ambient pressure within a few kPa, otherwise one trip and 5 s are enough; with the engine running it is held against a modelled manifold pressure and may not overshoot the model's maximum or undershoot its minimum by more than about 2 kPa; and if the signal moves by less than 10 kPa although conditions should make it vary, the sensor is treated as frozen (two trips). Leaks downstream of the throttle, a blocked sensor port, ice or a drifting sensor are typical reasons.

Likely causes

Air leak in the bank 2 intake behind the throttle
Sensor port blocked by deposits or frozen condensate
Sensor B drifting so that its reading no longer matches ambient or model

Symptoms

  • Check engine light on
  • Hesitation or uneven idle
  • Mixture or load faults on bank 2

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–350
Time0.5–2 h

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

Parts involved

map sensor bwiring harnessecm

Related codes

P2A0AP2A0CP2A0DP2A0EP0106

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