Coolant Pump (V50) (Coolant Pump (V36)), Checking Function
Coolant Pump (V50) (Coolant Pump (V36)), Checking Function
Special tools, testers and auxiliary items required
• Vehicle Diagnostic, Testing and Information System (VAS 5051 A) with Diagnostic Cable (VAS 5051/5A)
• Battery charger, 60A (VAS 5904)
• Standard thermometer (for temperature measurements, if necessary use a thermometer with 2 measuring probes for simultaneous measurement for example, for temperature at right and left)
In this test, function of Coolant Pump (V50) (of Coolant Pump (V36) ) will be checked.
• If the determined temperatures lie below the specification (heating performance too low):
- Check function of control motors for temperature doors and their connections to the temperature doors as well as Coolant Pump (V50) (and Coolant Pump (V36) ) using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
If no malfunctions are detected:
- Check coolant hoses (from engine via Coolant Pump (V50) ( Coolant Pump (V36) ) to heater cores in front and rear heating & A/C units for interchange, refer to => [ Incorporation of Front HVAC System into Cooling Circuit ] Incorporation of Front HVAC System Into Cooling Circuit.
- Check electrical contacts of Coolant Pump (V50) (of Coolant Pump (V36) ) for interchange (running direction of pump changes when connections are interchanged).
Test Requirements
• The coolant circuit has been bled according to the specifications. Refer to=> [ Coolant System, Bleeding ] Coolant System, Bleeding.
• All air ducts, covers and seals OK and properly fitted
• Air flow through dust and pollen filter (in front heating & A/C unit) is not impaired by soiling (removing and installing dust and pollen filter, refer to => [ Dust and Pollen Filter ] Service and Repair).
• Vehicle battery is OK and sufficiently charged (so that Energy Management Control Module (J644) does not shut off activation of Climatronic Control Module (J255) and Rear A/C Display Control Head (E265) during the test).
• Engine warm
• DTC memory of Climatronic control module (and of rear A/C display control head) was checked and erased, basic setting was performed and coding of Climatronic control module was checked using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
• Adaptation of Climatronic control module (and rear A/C display Control Head) was checked using Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding".
• Vehicle not exposed to sunlight
Check the Function
- Close hood.
- Close doors, windows and sun roof.
- Start engine and let it run a few minutes at maximum cooling performance (compressor is switched on, temperature preselect LO for left and right sides at front and if necessary at rear, or temperature preselect rotary switch stands at cold stop).
- Switch off ignition.
- On vehicles with Comfort version A/C system, connect (VAS 5051 A) with (VAS 5051/5A) to 16-pin Data Link Connector (DLC) in vehicle with ignition switched off and select heating / A/C electronics on Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- Start the engine.
Climatronic control module (and rear A/C display Control Head) starts up.
• At this setting, Coolant Pump (V50) ( Coolant Pump (V36) ) is not actuated by the A/C system. Depending on coolant temperature, Coolant Pump (V50) ( Coolant Pump (V36) ) may possibly be actuated by Engine Control Module (ECM), check using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
Testing front A/C system
Cold air flows from instrument panel vents and vents in center console and in B and C pillars (on vehicles with a rear A/C system).
- If the vehicle has the Comfort A/C system, read the measured values from the Left Front Upper Body Vent Temperature Sensor (G385) and the Right Front Upper Body Vent Temperature Sensor (G386) on the Climatronic control module using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- On vehicles with Basic version A/C system, measure temperature of air flowing from instrument panels vents on left and right sides, for example, using a thermometer.
- A value below 20 °C (68 °F) or a temperature below 20 °C (68 °F) measured with a thermometer is displayed in the display fields with the measured values from the left front upper body vent temperature sensor and right front upper body vent temperature sensor.
• If the temperature measured 5 minutes after starting engine is still greater than 20 °C, perform cooling performance test => [ Test Requirements ] Test Requirements.
- Set the Climatronic control module pre-selector to HI for the left and right sides at front or temperature preselect rotary switch to the warm stop.
- Observe the display in the display fields with the measured values from the left front upper body vent temperature sensor and right front upper body vent temperature sensor, or, measure of air flowing out of instrument panel vents on left and right sides in alternation using a thermometer. At an engine temperature of approximately 90 °C (194 °F), the displayed or measured temperature must be greater than 70 °C (158 °F) on left and right sides after a short period of time. At a lower engine temperature, it must correspond approximately to the current engine temperature (permissible deviation 20 °C (68 °F) maximum).
• Depending on version of Instrument Cluster Control Module (J285) , a coolant temperature of for example, 90 °C (194 °F) is always displayed in instrument cluster within a certain temperature range of coolant temperature (engine temperature), the temperature displayed can therefore deviate from the actual coolant temperature.
• If engine temperature deviation is greater than 20 °C (68 °F) or greater than 10 °C (50 °F) between measured values at left and right sides, check ventilation of heater core, refer to => [ Coolant System, Bleeding ] Coolant System, Bleeding and activation and function of temperature door control motors, refer to => [ Retaining Plate With Left Footwell Door Motor (V108) and Left Temperature Door Motor (V158) ] Retaining Plate With Left Footwell Door Motor (V108) and Left Temperature Door Motor (V158), => [ Retaining Plate With Control Motors (V158) ((V159)) and (V109) ((V108)) ] Retaining Plate With Control Motors (V158) ((V159)) and (V109) ((V108)) and Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- Increase engine speed up to approximately 3000 RPM in several stages.
- Observe the display in the display fields with the measured values from the left front upper body vent temperature sensor and right front upper body vent temperature sensor, or, measure of air flowing out of instrument panel vents on left and right sides in alternation using a thermometer. The displayed or measured temperature must not change significantly (or must rise or fall along with engine temperature).
• If the displayed or measured temperature changes by more than approximately 10 °C (50 °F) or is lower in one speed range, check incorporation of A/C system into cooling circuit => [ Incorporation of Front HVAC System into Cooling Circuit ] Incorporation of Front HVAC System Into Cooling Circuit and incorporation and activation of Coolant Pump (V50) ( Coolant Pump (V36) ) using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- Switch engine off and then ignition on again.
- Set an intermediate fresh air blower speed on the Climatronic control module.
• At maximum fresh air blower speed, the delivery rate of Coolant Pump (V50) ( Coolant Pump (V36) ) is no longer sufficient and the outlet temperature sinks relatively quickly to a value of approximately 40 °C (104 °F).
- Perform Guided Fault Finding on the A/C system and read the display in the measured values block display group with the measured values from the left front upper body vent temperature sensor and right front upper body vent temperature sensor or measure temperature of air flowing out of instrument panel vents on left and right sides.
- While doing this, observe the display fields with the measured values from the left front upper body vent temperature sensor and right front upper body vent temperature sensor, or the alternating measured values of thermometer (measure temperature of air flowing out of instrument panel vents on left and right sides). The displayed or measured temperature sinks slowly along with the engine coolant temperature.
• If the displayed or measured temperature decreases relatively quickly, check activation and function of Coolant Pump (V50) ( Coolant Pump (V36) ) using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
Testing Rear A/C system (only for vehicles with this optional equipment)
• Before testing rear heating performance, front heating performance must be check, only if this is OK is the rear heating performance to be checked.
• When testing front heating performance, the temperature preselect Lo is set for the left and right sides on rear A/C display Control Head, it must remain at this setting when starting the test for the rear.
- Start engine.
- On vehicles with a rear A/C system, perform Guided Fault Finding for rear A/C display control head of A/C system using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- In the rear A/C display control head select "read measured values block" the display group with the measured values from the Left Rear Vent Temperature Sensor (G405) and the Right Rear Vent Temperature Sensor (G406) on the Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function
- A value below 20 °C (68 °F) is displayed in the display fields with the measured values form the left rear vent temperature sensor and the right rear vent temperature sensor.
• If the temperature measured 5 minutes after starting engine is still greater than 20 °C (68 °F), perform cooling performance test => [ Test Requirements ] Test Requirements.
- Set temperature preselect to HI for left and right sides on rear A/C display control head.
- Observe the display with the measured values from the left rear vent temperature sensor left rear vent temperature sensor and the right rear vent temperature sensor right rear vent temperature sensor. The temperature displayed must correspond approximately to the current engine temperature on left and right sides after a short period of time (permissible deviation maximum 20 °C).
• If deviation for engine temperature is greater than 20 °C (68 °F), or between left and right measured values greater than 10 °C (50 °F), check ventilation of heater core, refer to => [ Coolant System, Bleeding ] Coolant System, Bleeding, incorporation of rear A/C system into cooling circuit => [ Incorporation of Front HVAC System into Cooling Circuit ] Incorporation of Front HVAC System Into Cooling Circuit , activation of function of control motors for temperature doors in rear heating & A/C unit ( Right Rear Temperature door Motor (V314) => [ Right Rear Temperature Door Motor (V314) ] Right Rear Temperature Door Motor (V314) and Left Rear Temperature door Motor (V313) => [ Left Rear Temperature Door Motor (V313) ] Left Rear Temperature Door Motor (V313)) and of Coolant Pump (V50) ( Coolant Pump (V36) ) using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- Switch engine off and then ignition on again.
- Set an intermediate fresh air blower speed on rear A/C display control head.
• At maximum fresh air blower speed, the delivery rate of Coolant Pump (V50) ( Coolant Pump (V36) ) is no longer sufficient and the outlet temperature sinks relatively quickly to a value of approximately 40 °C (104 °F).
- Perform Guided Fault Finding and read the display with the measured values from the left rear vent temperature sensor and the right rear vent temperature sensor.
- Observe the display with the measured values from the left rear vent temperature sensor and the right rear vent temperature sensor. The displayed temperature sinks slowly along with the engine coolant temperature.
• If the displayed or measured temperature decreases relatively quickly, check activation and function of Coolant Pump (V50) ( Coolant Pump (V36) ) Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.