P0AAE

Code

Generic P — Powertrain

Hybrid/EV Battery Pack Air Temperature Sensor A Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 18 EN: 15 RU: 13

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Short to ground in the sensor signal wire
Poor or corroded connector or pin at the sensor or control module
Damaged or chafed wiring harness between sensor and battery management/ECU
Failed/shorted battery pack air temperature sensor (internal short)
Faulty battery management system (BMS) / control module input
Water ingress or contamination at sensor/connector

Symptoms

DTC P0AAE stored (illumination depends on manufacturer)
Incorrect or implausible battery pack air temperature reading (very low or pegged)
HV battery cooling/heating or climate control may operate improperly
Reduced EV/hybrid performance or limited charging/discharging (safety limp mode on some vehicles)
Possible warning lamp or message about hybrid/EV battery system

What to check

Scan tool: read freeze frame, MIL status, pending/confirmed count, and live data for battery pack air temperature and related sensors
Visually inspect the air temperature sensor, mounting area and connector for corrosion, damage, water intrusion or contamination
Backprobe the sensor connector (with vehicle safely made unserviceable if HV work required) to measure signal voltage and reference voltage with ignition on
Measure sensor resistance (thermistor) at ambient temperature with sensor disconnected from harness
Check continuity and insulation to ground on signal wire; look for short to chassis ground
Wiggle test wiring harness while monitoring live data for intermittent changes

Signal parameters

Expected signal voltage (typical): ~0.5–4.5 V depending on temperature and manufacturer; a 'low' circuit fault often registers below ~0.2–0.5 V
Typical thermistor resistance example (varies by design): ~10 kΩ at 25°C for many NTC sensors — consult vehicle spec
Open-circuit resistance: very high (>>50 kΩ) or infinite; short to ground: very low (
Operating temperature range for air temperature sensors: about -40 °C to +125 °C (sensor curve expected to change accordingly)

Diagnostic algorithm

Read and record DTC details, freeze-frame data and live sensor values with a scan tool. Note if code is confirmed or pending and whether multiple related codes are present.
Follow manufacturer procedures to safely disable/isolate the high-voltage system before performing any hands-on tests near the HV battery. Do not attempt HV work without appropriate training and PPE.
Visually inspect the battery pack air temperature sensor, connector, seals and harness for damage, corrosion, moisture or detachment.
With the vehicle in the correct (safe) state for low-voltage checks, backprobe the sensor connector and verify reference voltage (usually a pull-up/reference of ~5 V or other specified value) and ground continuity at the ECU/BMS connector with ignition ON.
Measure the sensor signal voltage with ignition ON and compare to expected range. A very low voltage suggests a short to ground or shorted sensor.
Disconnect the sensor from the harness and measure sensor resistance at ambient temperature. Compare to manufacturer specification or expected NTC curve. Replace if out of range or shorted.
Check continuity and resistance of the signal and ground wires between the sensor connector and the BMS/ECU. Look for short to ground, short to power, or open circuits.
If wiring checks are good and the sensor is within spec, inspect BMS/ECU connector pins for damage. If possible, swap with a known-good identical input (if supported) or substitute a known-good sensor to confirm.
Replace or repair any damaged wiring, connectors, or the sensor. After repairs, clear codes and perform a test drive or battery system exercise to verify the fault does not return.
If the fault persists after sensor and wiring replacement, consider BMS/ECU input fault and consult manufacturer service information or an authorized repair facility for module diagnostics/repair.

Likely causes

Connector damage or corrosion at sensor
Wiring short to ground in harness near sensor
Failed thermistor sensor element
Intermittent connection or poor ground at BMS/ECU

Fault status

⚠️ Status

Battery pack air temperature sensor A circuit voltage below expected/low input. Possible short to ground, damaged sensor, wiring/connector fault, or BMS/ECU input problem.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1-3 hours