OBD-II code · Powertrain (generic, extended)
P257A Vacuum Reservoir Control Circuit/Open
The control circuit that drives the vacuum reservoir control valve (or vacuum pump motor) is open. The ECM cannot energise the actuator, so vacuum is no longer maintained on demand and consumers like brake booster, EGR or HVAC dampers may run out of vacuum.
Is it safe to drive with P257A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen control wire
- PossibleFailed driver in the control module
- Less likelyPin pushed back out of connector body
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Vacuum Reservoir Control Valve, Wiring Harness
Related codes
- P2577Direct Ozone Reduction Catalyst Efficiency Below Threshold
- P2578Turbocharger/Supercharger Speed Sensor A Circuit
- P2579Turbocharger/Supercharger Speed Sensor A Circuit Range/Performance
- P257BVacuum Reservoir Control Circuit Low
- P257CVacuum Reservoir Control Circuit High
- P257DEngine Hood Switch Circuit Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.