P0AAE: Hybrid/EV Battery Pack Air Temperature Sensor A Circuit Low

What does P0AAE mean?

The battery air temperature sensor is an NTC thermistor, so a low signal voltage reads as very hot air. P0AAE sets when the signal stays below the lower limit, usually a short to ground. GM's 2013 table (13OBDG05C) uses under 0.3 V, about 90 °C, in 7 of 10 samples; the two-mode hybrid tables of 2011 and 2013 flag an inlet reading above 95 °C in 30 of 40 samples. Both are Type B, two trips. Since the controller then assumes overheated cooling air, it may run the fan hard and cut battery power although nothing is hot. Look for chafed sensor wires touching ground or a sensor shorted internally. The opposite case, an open circuit reading as very cold, is P0AAF.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine or hybrid warning light
• Battery cooling fan runs at high speed without reason
• Reduced electric assist and regeneration

Common causes

• High Sensor signal wire chafed and shorted to ground
• Medium Thermistor shorted internally
• Low Battery controller input fault

Likelihood is a general estimate across vehicles; your make and model may differ.