Coolant RECIRCULATION Pump -V50- Function
The Coolant Recirculation Pump -V50- is currently not installed in all vehicles. Refer to CONNECTION DIAGRAM - COOLANT HOSES . If a parking heater is installed as optional equipment in vehicles, a Coolant Recirculation Pump -V50- may not be installed. The Recirculation Pump -V55- installed in vehicles with a parking heater assumes this function. The discontinuation of the Coolant Recirculation Pump -V50- has not been implemented in all vehicles. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function and refer to the appropriate Wiring Diagram(s).
The activation of the Coolant Recirculation Pump -V50- is different. For most vehicles the respective Engine Control Module -J623- (or from the Vehicle Electrical System Control Module -J519-) is activated at the request of the Front A/C Display Control Head -E87-. Refer to the appropriate Wiring Diagram(s).
Function
- The Coolant Recirculation Pump -V50- -A- supports the engines own coolant pump during coolant recirculation. It is activated by the Engine Control Module -J623- (or from the Vehicle Electrical System Control Module -J519-) at the request of the Front A/C Display Control Head -E87- to ensure sufficient and even coolant flow through the heater core(s) of the heating and A/C system. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function.
- With the Coolant Recirculation Pump -V50- -A- running the coolant on most vehicles is extracted via the coolant hose -C- from the engine and pumped via the coolant hose -B- to the heater and A/C unit heater core. Via the heat exchanger in the heater and A/C unit and if equipped the Coolant Shut-Off Valve -N82- (depending on the version of the engine and the vehicle equipment) it flows back to the engine. Refer to INCORPORATING THE HEATING AND A/C SYSTEM IN THE COOLANT CIRCUIT .
- The Coolant Recirculation Pump -V50- -A- is activated when the ignition is turned on, depending on the coolant temperature and the adjustment on the Front A/C Display Control Head -E87- from Engine Control Module -J623- (or from Vehicle Electrical System Control Module -J519-). Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function and refer to the appropriate Wiring Diagram(s).
- Depending on the version of the vehicle the Coolant Recirculation Pump -V50- -A- is also activated by the request from the Front A/C Display Control Head -E87- from the Engine Control Module -J623- (or from the Vehicle Electrical System Control Module -J519-) when the parking heater is on or in the "residual heat function". Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- On vehicles with a "Start/Stop System" the Coolant Recirculation Pump -V50- -A- (and if equipped the Coolant Shut-Off Valve -N82-) are activated by a request from the Front A/C Display Control Head -E87-. The Heater Coolant Shut-Off Valve -N279- (and the Recirculation Pump -V55- if equipped are activated via the Auxiliary Heater Control Module -J364- by a request from the Front A/C Display Control Head -E87-. Refer to CONNECTION DIAGRAM - COOLANT HOSES , the appropriate Wiring Diagram(s) and Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- If errors are determined on these components and in the Front A/C Display Control Head -E87- no activation is stored. Therefore pay attention to the version, coding and adaptation of the Front A/C Display Control Head -E87-. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Coolant Recirculation Pump -V50-, Removing and Installing. Refer to ELECTRIC COOLANT PUMP, REMOVING AND INSTALLING .