Powertrain
generic / SAE
P257B
Vacuum Reservoir Control Circuit Low
The vacuum reservoir control circuit reads stuck low — short to ground or low-side driver stuck on. The actuator may be energised continuously when it should be off.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 7B
Possible causes
- Control wire shorted to ground high
- Connector pins corroded - high contact resistance low
- Harness chafing through insulation low
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 120–600 €
- Estimated time: 0.5–2 h
- Component: vacuum reservoir control valve
- MIL / check engine light
Sources
References
sae:J2012