Description & Function
The electric vacuum pump is only installed in vehicles with automatic transmission. It is switched on by Engine Control Module (ECM) depending on intake manifold pressure. Vacuum pump is On Board Diagnostic (OBD) capable. Detected malfunctions are stored in Engine Control Module (ECM) memory. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. Testing function of electric vacuum pump via On Board Diagnostic (OBD) must only be performed with engine at standstill.