P0D71

What it means

P0D71 is a generic powertrain code meaning the A/C compressor control module has found a performance problem with its internal temperature sensor 'A'. The module compares the reading with expected values, such as other temperature inputs or how the temperature should change after start-up, and sets the code when the reading looks implausible, stuck or drifting. The exact test and the position of the module depend on the vehicle, and this code is most often seen on hybrid and electric vehicles with an electric compressor.

Symptoms

• Warning light on, which may be the main warning or a hybrid system or A/C fault message
• A/C blowing warm or not cooling properly
• A/C compressor not running or shutting down intermittently
• Reduced A/C performance in hot weather
• Reduced cabin cooling or battery cooling on some hybrid and electric models
• Other A/C or thermal management codes stored alongside it

Possible causes

• Fault inside the A/C compressor control module or its integrated temperature sensorlikely
• Corroded, loose or damaged connector or wiring to the compressor module, including its power and ground supplieslikely
• Module overheating because of poor A/C system performance, such as low or incorrect refrigerant charge or a blockagepossible
• Poor cooling of the module on models where it is cooled by coolant or airflow, for example a restricted flow or low coolant levelpossible
• Low or unstable system voltage causing implausible sensor readingspossible
• Outdated control module software where the manufacturer has issued a fix for this faultrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including module temperature, ambient temperature and battery voltage
2. Check for related A/C, thermal management or communication codes, and diagnose those first as they may be the root cause
3. Inspect the compressor module connector and wiring for corrosion, water ingress, chafing and loose pins
4. Check the battery condition and charging voltage, and check the module's power and ground supplies against the wiring diagram
5. Check the A/C refrigerant charge and pressures, and look for blockages, using the correct recovery and charging equipment
6. Where the module is liquid or air cooled, check coolant level, flow and airflow as specified for that model
7. Compare live module temperature with other temperature readings when the car has been cold-soaked; a sensor that is stuck or far out suggests an internal fault
8. Check for a manufacturer software update or service bulletin for the specific model

How to fix

• Repair or replace damaged wiring and clean or replace corroded connectors
• Correct any power, ground or battery voltage problems
• Correct the A/C system fault, such as a leak, wrong charge or restriction, using proper refrigerant handling
• Restore cooling to the module by fixing coolant level, flow or airflow faults where the design requires it
• Replace the A/C compressor or its control module if the internal sensor is confirmed faulty, following the model's procedure
• Apply a manufacturer software update if one is available for this fault

Can I keep driving?

Nearby codes

• P0D70GenericA/C Compressor Control Module Internal Temperature Sensor A Circuit
• P0D72GenericA/C Compressor Control Module Internal Temperature Sensor A Circuit High