A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- The vacuum sensor connector or wiring
- The sensor itself
- A cracked or detached brake booster vacuum hose
- The vacuum pump (on diesels and some petrol engines)
What you can do yourself
- If the brake pedal has become hard, soft or sinks, or the car brakes worse — don’t drive, call a tow truck.
- Listen for hissing at the brake booster and check the vacuum hose from the engine to the booster.
Stop and don’t drive on if:
- The red brake light is on, or the brake pedal feels soft or sinks
- The steering became very heavy, or the car pulls to one side when braking
OOleg’s tip: check the connector
Often the cause is simple — there is no contact in the connector (plug). Look at the connector from the back: remove the rubber seal and you will see whether a wire is corroded or has come off completely. Corrosion shows up as green deposits. Ideally, gently pull each wire towards you one at a time: a sound wire stays in place, while a corroded one simply comes off — it needs to be repaired.
Unplug and inspect connectors with the ignition off.
Find the part on Kaspi ShopBefore buying, check the part number or match the part by VIN in the Kaspi “Garage”.
The explanation comes from the error code reference in the AvtoElektrik PRO app.