Powertrain, generic · Hybrid propulsion

P0AB4 Hybrid/EV Battery Pack Air Temperature Sensor B Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0AB4 reports a signal from air temperature sensor B above the valid range. For an NTC thermistor that reads as extremely cold air, which points to an open circuit, a broken ground or a disconnected plug. GM uses the code for the outlet air sensor of its full-size two-mode hybrids; the 2011 and 2013 tables set it when the outlet reading falls below -45 °C in 30 of 40 samples, Type B, two trips. With the outlet value rejected, the controller also suspends the outlet plausibility test P0AB2 and runs the fan on a substitute strategy. Look for a connector left off after battery work or a broken wire at the duct. The shorted counterpart is P0AB3, the inlet-side equivalent P0AAF.

Likely causes

Open signal or ground wire of sensor B
Connector not refitted after battery or duct work
Thermistor open internally

Symptoms

  • Check engine or hybrid warning light
  • Outlet air shows about -40 °C in live data
  • Battery fan on default operation

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–2.5 h

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

Parts involved

hv battery pack air temp sensor bwiring harnessbms

Related codes

P0AB3P0AB1P0AB2P0AB5P0AAF

References: gsi.ext.gm.com, gsi.ext.gm.com.