A/C Refrigerant Pressure Sensor Circuit High
The P2518 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the A/C refrigerant pressure sensor that is higher than the expected range. This sensor monitors the pressure of the refrigerant in the A/C system to control compressor operation and cooling fan speed. A high circuit condition typically means the sensor is sending a voltage above the normal operating range, which can be caused by a faulty sensor, wiring issues, or a short circuit. This can lead to improper A/C system operation, such as the compressor not engaging or the cooling fans running continuously.
01. Most Common Causes
- Faulty A/C refrigerant pressure sensor
- Short circuit in the sensor wiring or connector
- Corroded or damaged sensor connector
- High refrigerant pressure due to overcharge or blockage
02. Symptoms You Will Notice
- A/C compressor not engaging
- A/C system blowing warm air
- Cooling fans running continuously or not at all
- Check Engine Light illuminated
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve the code and check live data for the A/C pressure sensor voltage.
Step 2: Visually inspect the sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage output with a multimeter; compare to manufacturer specifications.
Step 4: Check refrigerant pressure with a manifold gauge set to rule out overcharge or blockage.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the A/C system may not work properly. Driving without A/C is safe, but if the cooling fans malfunction, engine overheating could occur in hot conditions.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and sensor replacement, plus refrigerant recharge if needed. Total cost can be higher if wiring repairs are required.