P2527
Vacuum Reservoir Pressure Sensor Circuit Low
Vacuum reservoir / idle control
Generic OBD-II
Medium
What it means
P2527 means the vacuum reservoir pressure sensor is sending a signal that's too low, usually from a wiring short, an open circuit, or a failed sensor. The reservoir stores vacuum for systems like brake assist and emissions actuators, so the fault mainly affects those functions rather than how the engine runs.
Medium
Can I keep driving? Usually drivable, but systems that rely on stored vacuum — such as brake assist or emissions actuators on some vehicles — may not work correctly, so have it checked.
Common symptoms
What you'll notice
- Check-engine light on
- Vacuum-operated systems may behave inconsistently
- Possible harder brake pedal on vehicles that use the reservoir for brake assist
- Often no obvious driving symptom
Common causes
Most likely first
- Faulty vacuum reservoir pressure sensorLikely
- Short to ground or open in the sensor's signal wiringCommon
- Corroded or loose sensor connectorCommon
- Loss of the 5-volt reference or ground to the sensorLess often
- Cracked or leaking vacuum lines to the reservoir affecting the readingLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check the sensor's live reading with a scan tool.
- Inspect the sensor connector and wiring for a short to ground, an open, or corrosion.
- Verify the reference voltage and ground at the sensor connector.
- Check the vacuum lines and reservoir for leaks or blockage.
- Replace the sensor if its signal stays low with good wiring, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2527?+
Usually yes, but if the reservoir feeds brake assist you may notice a firmer pedal, so have it inspected promptly.
Can I just clear P2527?+
It will return until the sensor or wiring fault is repaired. Clearing only turns the light off temporarily.
Related codes
Often seen with P2527
Read & clear P2527 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX