Check the heating output of the A/C system

Check the heating output of the A/C system at an engine speed of approximately 1500 to 2000 RPM (repeat the test at a higher engine speed). If the required heating output is reached at this engine speed, the malfunction is not in the heater and A/C unit, but rather in the coolant circuit (integration of the A/C system in the coolant circuit, engine coolant pump delivery rate, the coolant flowing through heater core in the front heater and A/C unit, incorporation of the Coolant Recirculation Pump -V50-, or the Thermal Management Coolant Pump 2 -V618- (on vehicles with a high-voltage system), in the coolant circuit, etc.)). Refer to HEATING AND A/C SYSTEM, INTEGRATING IN ENGINE COOLANT CIRCUIT and COOLANT, DRAINING AND FILLING .
Check the activation and function of the Coolant Recirculation Pump -V50- (the Recirculation Pump -V55- or Thermal Management Coolant Pump 2 -V618- on vehicles with a high-voltage system) and of the Coolant Shut-Off Valve -N82- (the Heater Coolant Shut-Off Valve -N279- or the Coolant Change-Over Valve 3 -N634- on vehicles with a high-voltage system) using the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
Check the integration of the A/C unit in the engine coolant circuit. Refer to HEATING AND A/C SYSTEM, INTEGRATING IN ENGINE COOLANT CIRCUIT .
Check the engine coolant circuit bleeding. Refer to COOLANT, DRAINING AND FILLING .
Check that the engine coolant pump is functioning correctly (if a coolant pump is faulty or a Coolant Recirculation Pump -V50- (Thermal Management Coolant Pump 2 -V618- on vehicles with a high-voltage system) is incorrectly integrated, there may not be enough coolant flowing through the heater core for the heater in the front heater and A/C unit)). Refer to OVERVIEW - ELECTRIC COOLANT PUMP .