A/C Refrigerant Pressure Sensor B Circuit Intermittent
The P2518 code means the vehicle's onboard diagnostic system has detected: A/C Refrigerant Pressure Sensor B Circuit Intermittent. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $80 - $350 (parts and labor)
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Common Symptoms
- A/C cooling works intermittently
- A/C compressor engages and disengages erratically
- Sporadic check engine light
- Inconsistent A/C performance
Probable Causes (Ranked by Likelihood)
- Loose A/C pressure sensor connector Very High
- Intermittent sensor internal failure High
- Damaged sensor signal wire insulation Moderate
- ECM A/C input circuit sensitivity Low
Step-by-Step Diagnostic Procedure
-
Wiggle test pressure sensor connector while monitoring signal
-
Check sensor connector pins for spread or corrosion
-
Inspect sensor signal wire routing for chafing
-
Monitor sensor data PID for erratic readings
Frequently Asked Questions
Why does my A/C work sometimes but not others?
The intermittent sensor signal causes the ECM to alternately see normal and abnormal pressure readings, enabling and disabling the compressor unpredictably.
Is P2518 worth fixing if A/C mostly works?
Yes. The intermittent fault will likely worsen over time, and erratic compressor cycling can cause premature compressor wear.
How do I find an intermittent sensor fault?
Monitor the sensor data PID on a scan tool while tapping and wiggling the sensor and its connector. An intermittent fault will show as sudden signal jumps.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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