Is it safe to drive with this code?

Continuing to drive may be possible in the short term, though the hybrid system may operate with reduced efficiency or enter a protective mode limiting electric assist. If the battery pack cannot monitor its own temperature properly, there is potential for overheating or reduced longevity. It's advisable to have the fault diagnosed promptly; see our disclaimer regarding driving with active fault codes.

The MOT examiner will check whether the malfunction indicator lamp (engine warning light) is illuminated at the time of the test. If the MIL is lit and the tester cannot verify emission or safety-critical systems are functioning correctly, a failure may be recorded. The outcome depends on the tester's assessment—see our MOT disclaimer for full details.

Roughly how much does it cost to fix?

Repair costs vary considerably depending on the root cause. If the issue is a poor connection or corroded pins, the fix may fall into the low two-figure range for cleaning and reseating. Replacing a faulty air temperature sensor integrated into the battery pack assembly typically ranges from low to mid three-figure sums, whilst more complex faults involving battery pack removal or control module replacement can reach high three-figure or even four-figure territory at a franchised dealer. Independent hybrid specialists often charge less than main dealers for labour.

Can I clear the code and see if it returns?

Clearing the code and monitoring for recurrence can help determine whether the fault is intermittent. However, the underlying cause—such as a degraded sensor or poor connection—will typically trigger the code again. Proper diagnosis is recommended to address the root issue rather than repeatedly clearing stored faults.

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← All fault codes | Electrical & Sensors

P0AAC

Powertrain

Hybrid Battery Pack Air Temperature Sensor (ATS) "A" Circuit

The high-voltage battery control module has identified an issue with the circuit reading from the air temperature sensor located within the hybrid battery pack assembly.

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ⓘ Information only. This page provides general educational information about fault code P0AAC. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.

Recommended next steps

Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.

What does P0AAC mean?

P0AAC is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Hybrid Battery Pack Air Temperature Sensor (ATS) "A" Circuit.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

About Electrical & Sensors codes

Codes in the Electrical & Sensors category.

P0AAC is one of 4,010 codes in this category. Browse all Electrical & Sensors codes →

What we know about P0AAC specifically

We record the SAE J2012 standardised definition and the system this code belongs to, but we have not yet published detailed driver-reported symptoms, common causes, or step-by-step diagnostic guidance for P0AAC.

Rather than invent that information by generating generic content from a template, we leave it out. For specific guidance, the most reliable sources are:

•your vehicle's own service manual or manufacturer-specific technical bulletins
•a qualified mechanic with a manufacturer-level diagnostic tool
•a marque specialist familiar with your make and model

Codes nearby

Codes adjacent to P0AAC in the P-code series. Many fault codes appear together with their neighbours because they relate to the same circuit or component.

P0AA9 Hybrid Battery Voltage Isolation Sensor Circuit Low

P0AAA Hybrid Battery Voltage Isolation Sensor Circuit High

P0AAB Hybrid Battery Voltage Isolation Sensor Circuit Intermittent/Erratic

P0AAD Hybrid Battery Pack Air Temperature Sensor (ATS) "A" Circuit Range/Performance

P0AAE Hybrid Battery Pack Air Temperature Sensor (ATS) "A" Circuit Low

P0AAF Hybrid Battery Pack Air Temperature Sensor (ATS) "A" Circuit High

Other Electrical & Sensors codes

Other fault codes in the same system as P0AAC. The ones with detailed guides have plain-English explanations, symptoms, causes, and diagnostic steps.

B1257

Air Temperature External Sensor Circuit Short To Ground Detailed guide

B1363

DBPT Circuit Short To Ground Detailed guide

B2100

Ignition Run/Start Input Circuit Performance Detailed guide

C2000

Steering Angle Sensor Not Calibrated Detailed guide

P0030

HO2S Heater Control Circuit (Bank 1 Sensor 1) Detailed guide

P0031

Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1) Detailed guide

Spotted an issue or have something to add? Mechanics, technicians, and drivers who have first-hand experience with P0AAC can submit a correction or expansion. We review every submission before publishing, mechanic submissions are prioritised.

Information only, not professional advice

The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →

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