P258B

Vacuum Pump Control Circuit A Range/Performance

Q: Is it safe to drive with P258B?

Be cautious — if the pump assists the brakes, stopping can take more effort. Have it inspected promptly and allow extra braking distance.

Q: Can I just clear P258B?

It returns until the pump or its control circuit is repaired. Clearing only turns the light off temporarily.

Vacuum pump (brake/emissions assist) Generic OBD-II Medium

What it means

P258B means the vacuum pump control circuit 'A' isn't performing as the computer expects. Many vehicles use this pump to supply vacuum for brake assist (and some emissions functions), so a fault can make the brake pedal feel firm and increase stopping effort. It usually traces to the pump, its control wiring, or the vacuum plumbing.

Medium

Can I keep driving? Drive with care — if this vacuum pump supplies brake assist, the pedal can feel hard and braking effort increases, so have it checked promptly.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Firmer brake pedal or more effort to stop (on vacuum-assisted brakes)
Vacuum-operated systems working inconsistently
Sometimes no obvious symptom beyond the warning light

Common causes

Most likely first

Faulty vacuum pump or its control circuitLikely
Open, shorted, or high-resistance wiring in the pump control circuitCommon
Corroded or loose pump/connector contactsCommon
Faulty control relay or driver in the moduleLess often
Blocked, leaking, or collapsed vacuum lines affecting performance feedbackLess often

How to diagnose & fix

Work through it in order

Read freeze-frame data and command the vacuum pump with a scan tool to watch its response.
Inspect the pump control wiring, connector, and any relay for opens, shorts, or corrosion.
Check the vacuum lines and check valves for leaks or blockage.
Verify the pump gets power and ground when commanded on.
Repair the circuit or replace the vacuum pump as indicated, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P258B?+

Be cautious — if the pump assists the brakes, stopping can take more effort. Have it inspected promptly and allow extra braking distance.

Can I just clear P258B?+

It returns until the pump or its control circuit is repaired. Clearing only turns the light off temporarily.

Read & clear P258B yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX