XC90 L5-2.5L Turbo VIN 59 B5254T2 (2004)
Vacuum Brake Booster: Testing and Inspection
Checking the vacuum pump
Fault-tracing information
The vacuum pump raises the power brake booster efficiency when the negative pressure of the engine is too low, e.g. when the engine is switched off
(ignition on).
Operating difficulties may make the brake pedal stiff.
Reasons for the vacuum pump not working can include:
-
Open-circuit, short-circuit in the wiring to the vacuum pump
-
Defective vacuum pump switch
-
Defective vacuum pump.
Reasons for the vacuum pump operating constantly can include:
-
Short-circuit to supply voltage in the cable to the vacuum pump
-
Defective vacuum pump switch
-
Defective hoses to the vacuum pump.
Continue - Check the function of the vacuum pump
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Check the function of the vacuum pump