P2529
Vacuum Reservoir Pressure Sensor Circuit Intermittent
Vacuum / idle control
Generic OBD-II
Medium
What it means
P2529 means the sensor that monitors pressure in the engine's vacuum reservoir is giving an intermittent or erratic signal. The reservoir stores vacuum for systems such as the brake booster and vacuum-actuated controls, so an unreliable reading — usually a loose connector or failing sensor — can make those systems behave inconsistently.
Medium
Can I keep driving? Usually drivable, but stored vacuum feeds systems like the brake booster and vacuum-actuated controls — fix the intermittent sensor so those work reliably.
Common symptoms
What you'll notice
- Check-engine light on (sometimes intermittently)
- Occasional firmer brake pedal or weaker power-brake assist
- Erratic operation of vacuum-actuated systems
- Often no noticeable change between events
Common causes
Most likely first
- Intermittent open or short in the vacuum reservoir pressure sensor wiringLikely
- Loose or corroded sensor connectorCommon
- Failing pressure sensor with an internal intermittent faultCommon
- Loose or leaking vacuum hose at the reservoir affecting readingsLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and note when the fault appears.
- Wiggle-test the sensor connector and harness while watching live pressure data for dropouts.
- Inspect the connector for corrosion, spread pins, or damage.
- Check the vacuum reservoir and its hoses for leaks or loose fittings.
- Replace the pressure sensor if the intermittent is internal, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2529?+
Usually yes, but if brake-booster or other vacuum assist feels weaker, treat it as more urgent and get it checked promptly.
Can I just clear P2529?+
An intermittent fault will set it again as soon as the signal drops out; the wiring, connector, or sensor still needs repair.
Related codes
Often seen with P2529
Read & clear P2529 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