Powertrain, generic · Hybrid propulsion

P0AB1 Hybrid/EV Battery Pack Air Temperature Sensor B Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

Air temperature sensor B is a second thermistor in the battery cooling air path; in GM's two-mode hybrid tables it is the outlet air sensor behind the modules. P0AB1 is the general circuit code for it, used when the controller sees an electrical fault without sorting it into low, high or erratic. No manufacturer documents this exact code publicly; GM reports the siblings P0AB2 to P0AB4 instead. CARB requires temperature inputs of hybrid components to be monitored for circuit faults. Without a valid outlet value the controller cannot judge how much heat the air carries away, so it usually falls back to a default fan strategy and may limit battery power. Inspect the outlet-side connector and wiring first.

Likely causes

Damaged wiring or poor contact at the outlet air sensor
Air temperature sensor B failed
Battery controller input circuit fault

Symptoms

  • Hybrid or check engine warning light
  • Battery fan runs on a default setting
  • Possibly reduced electric assist

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 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

P0AB2P0AB3P0AB4P0AB5P0AAC

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