Vacuum Pump Control Circuit A/Open
What it means
P258A means the engine computer has detected an open in the control circuit for an electric vacuum pump. On many vehicles this pump supplies vacuum to the brake booster (and sometimes emissions actuators), so an open circuit can leave the pump inactive. The engine still runs normally, but on cars that rely on the pump for brake assist you may notice a firmer pedal. The fault is almost always wiring, the connector, the relay, or the pump itself.
Can I keep driving? Usually drivable, but on cars where this pump assists the brakes you may notice a firmer pedal — get it checked.
Common symptoms
What you'll notice
- Check-engine light on
- On some vehicles, a firmer/harder brake pedal (if the pump aids the booster)
- Often no noticeable change in how the engine runs
Common causes
Most likely first
- Open or shorted wiring in the vacuum pump control circuitLikely
- Corroded or loose connector at the pump or its relayCommon
- Faulty vacuum pump or pump relayCommon
- ECM driver fault (rule out wiring and relay first)Less often
How to diagnose & fix
Work through it in order
- Inspect the pump control connector and wiring for an open circuit or corrosion.
- Check the pump relay and its control/feed circuits.
- Confirm the pump runs when commanded; replace it if the circuit is good but it stays dead.
- Clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P258A?+
Can I just clear P258A?+
Related codes
Often seen with P258A
Read & clear P258A yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.