Code result
P257A
Vacuum Reservoir Control Circuit/Open
Moderate severity
What it means
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 The ECM cannot energise the actuator, so vacuum is no longer maintained on demand and consumers like brake booster, EGR or HVAC dampers may run out of vacuum.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?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Open control wire
highOne of the most commonly reported causes for this code — check this first.
Failed driver in the control module
mediumA plausible cause — test and verify before replacing parts.
Pin pushed back out of connector body
lowLess common, but worth ruling out after the more likely causes.
Related help
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