P2E7C: A/C Compressor Control Module Internal Temperature Sensor B Circuit

What it means

The ECM detects a circuit fault on the a/c compressor control module internal temperature sensor b. 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

Internal temperature sensor B monitors temperature inside the A/C compressor control module. The ECM checks the sensor circuit so the compressor can be controlled within safe conditions; this code sets when that circuit has a fault and the reading cannot be relied on.

Common causes

Most likely first.

1. Sensor failed
2. Wiring or connector fault

Symptoms

• Check-engine light may be on
• Air conditioning may be reduced or disabled

How to diagnose it

1. Use a scan tool to save freeze-frame data and check for sensor B readings and related A/C compressor control faults.
2. Inspect the accessible compressor control module connector and sensor B wiring for looseness, corrosion, moisture, or damage.
3. Check live data to see whether sensor B reports a plausible temperature or remains fixed, absent, or erratic.
4. Use the manufacturer's wiring diagram to test sensor B's circuit and connector continuity for an open, short, or poor contact.
5. If the circuit checks pass, test internal temperature sensor B against the manufacturer's specification.

Common fixes

• Reseat or clean the compressor control module connector if its contacts are serviceable.
• Repair damaged wiring or a poor connection in sensor B's circuit.
• Replace sensor B or the relevant serviceable module component if it fails the manufacturer's test.

Can I keep driving?

This fault may cause the A/C to be reduced or disabled, but it does not by itself establish a loss of engine braking or steering. If the compressor or hybrid system shows an overheating warning, stop safely and have the fault assessed.