What it means
The A/C refrigerant pressure sensor B circuit has an intermittent or erratic signal. The code does not establish the sensor’s location or whether the sensor or wiring is at fault.
At a glance
- Usually lights the check-engine light
How it works
A/C refrigerant pressure sensor B reports pressure to the control module for compressor control and system protection. This code sets when the sensor B circuit signal becomes intermittent or erratic, potentially causing the controller to interrupt or limit A/C operation.
Common causes
Most likely first.
- Intermittent contact at connector
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- A/C may cool intermittently or less effectively
- Check-engine or A/C warning light may illuminate
How to diagnose it
- Check freeze-frame data and live pressure readings for sensor B, comparing them with sensor A if available and with A/C operating conditions.
- Identify sensor B using the vehicle wiring information, then inspect its connector and harness for looseness, moisture, corrosion, or chafing.
- Monitor sensor B's reading while gently moving its connector and harness to see whether the signal jumps or drops out.
- Check the sensor B wiring and terminals for intermittent contact or damage using the manufacturer's procedure.
- If the circuit is sound, test sensor B and compare its reading with measured system pressure using the manufacturer's specifications.
Common fixes
- Secure the sensor B connector and harness if loose.
- Repair chafed wiring or replace corroded connector terminals and seals.
- Repair the intermittent circuit connection identified during testing.
- Replace sensor B if it continues to report erratically with a sound circuit.
Can I keep driving?
You can generally drive if the only symptom is intermittent or reduced A/C cooling. Switch the A/C off if the compressor makes unusual noise or system behavior changes, and arrange diagnosis so pressure information can be restored.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.