P0D71: A/C Compressor Control Module Internal Temperature Sensor A Performance

What it means

The ECM detects a performance fault on the a/c compressor control module internal temperature sensor a. Reading cannot be used reliably for control.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Temperature sensor A inside the A/C compressor control module tracks the module’s temperature so the system can manage heat safely. This code sets when the sensor signal does not change or respond as expected, even though the circuit may remain electrically connected.

Common causes

Most likely first.

1. Sensor characteristic drifted
2. High-resistance contact

Symptoms

• A/C warning light may come on
• Air conditioning may provide little or no cooling
• A/C operation may be limited or disabled

How to diagnose it

1. Record freeze-frame data and monitor internal temperature sensor A live data from a cold start through normal A/C operation for an implausible or unchanging response.
2. Inspect the compressor control module connector and harness for corrosion, weak terminal contact, or heat-related damage.
3. Check the sensor circuit for excessive resistance or voltage drop, particularly at connector and ground points.
4. Compare sensor readings at different module temperatures with the manufacturer’s specification to identify a drifted sensor response.
5. If the circuit and connections pass, test sensor A and the compressor control module using the manufacturer’s procedure.

Common fixes

• Clean and secure the sensor circuit connector terminals.
• Repair high-resistance wiring or ground connections.
• Replace internal temperature sensor A if its response falls outside the specified range.
• Replace or repair the compressor control module only if its sensor input fails the specified test.

Can I keep driving?

A/C operation may be limited or stopped because the module cannot trust its internal temperature feedback. Driving is usually possible if there are no other symptoms, but arrange diagnosis soon and use another method to clear window fog.