A/C Refrigerant Pressure Sensor B Circuit Low
The P2516 code means the vehicle's onboard diagnostic system has detected: A/C Refrigerant Pressure Sensor B Circuit Low. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- A/C not blowing cold air
- A/C compressor cycling rapidly
- Check engine light on
- A/C system warning light
Probable Causes (Ranked by Likelihood)
- Refrigerant pressure sensor shorted internally Very High
- Short to ground in sensor signal wire High
- Very low refrigerant charge Moderate
- Corroded sensor connector Moderate
Step-by-Step Diagnostic Procedure
-
Measure pressure sensor signal voltage at ECM connector
-
Check refrigerant pressure with manifold gauge set
-
Inspect sensor connector for corrosion or water intrusion
-
Test sensor wiring for short to ground
Frequently Asked Questions
Why is my A/C compressor cycling on and off with P2516?
The low pressure reading makes the ECM think the system is low on refrigerant, so it cycles the compressor off to protect it, then back on when it reads higher.
Can I just recharge the A/C to fix P2516?
If the system truly is low on refrigerant, a recharge may help. However, a faulty sensor will continue to send incorrect readings regardless of charge level.
How do I test the A/C pressure sensor?
With the engine off, measure the sensor output voltage. It should correspond to a specific pressure. Compare the reading with manifold gauge pressure to verify accuracy.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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