Powertrain, generic (extended)

P2A0C Manifold Absolute Pressure Sensor B Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2A0C reports that the MAP B signal voltage is too low. Manifold pressure sensors are usually three-wire parts fed from a 5 V reference; a signal close to zero means a broken reference or signal wire, a ground short or a dead sensor, because even deep vacuum would not pull a healthy sensor down that far. GM documents the code for the Corvette's LT6 V8, whose sensor B measures the manifold pressure of bank 2: a reading below 0.5 V for 1.5 s sets it after one trip. The bank-1 sensor reports the same condition as P0107. Once the signal is lost the module falls back on a modelled pressure for that bank, so the engine keeps running, but response and smoothness may suffer and power may be cut back.

Likely causes

5 V reference or signal wire open
Signal wire shorted to ground
Sensor B failed internally

Symptoms

  • Check engine light on
  • Sluggish response or rough running
  • Possible reduced engine power

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–250
Time0.3–1.5 h

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

Parts involved

map sensor bwiring harnessecm

Related codes

P2A0AP2A0BP2A0DP2A0EP0107

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