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Cooling performance checking (vehicles from model year 2002) Audi A6 C5 рестайлинг

Air Conditioning 3 illustrations ~1446 words

Cooling performance checking (vehicles from model year 2002)

  1. Measure ambient temperature (must greater than 15 ° C).
  2. Close doors, hood, window and sunroof.
  3. Open all dash panel vents.
  4. Switch ignition on.
  5. Select ECON mode on A/C control head -E87- (indicator light in ECON button lights up).
  6. Start engine.
  7. Connect VAG 1551 scan tool and press buttons -0- and -8-to insert AC/Heating Electronics" address word 08 and advance program until "Select function XX" appears on display. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  8. Initiate "Read Measuring Value Block" function 08 and select display group "001" for vehicles from model year 2002. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  9. Check indication in display fields: Display field "2" shows 0% (compressor is switched off) Display field "4" shows, that the pressure in the refrigerant circuit measured at ambient temperature is the same or greater as the value shown in «AMBIENT TEMPERATURE AND PRESSURE (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/automatic-hvac-system/#air-conditioning) table.
Ambient temperatures in ° CDisplayed pressure (in bar absolute pressure)
154.7
205.6
256.6
307.6
358.8

AMBIENT TEMPERATURE AND PRESSURE (VEHICLES FROM MODEL YEAR 2002)

Note. At absolute pressure, 0 bar corresponds to absolute vacuum. Normal ambient pressure corresponds to approximately 1 bar absolute pressure. 0 pressure corresponds to an absolute pressure of one bar on most pressure gauges (indicated by -1 below 0). The pressure in the refrigerant circuit depends on the ambient temperature. Via heat emission of components (e.g. coolant fan), with the engine at operating temperature a slightly higher pressure is displayed than the respective ambient temperature. If the displayed pressure is lower than in the table

  1. Check measuring value of High Pressure Sensor -G65-. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and Electrical Testing, «TEST STEP 5 TO 9»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  2. Not enough refrigerant in circuit, if no malfunction can be detected on high pressure sensor. Determine and eliminate the cause
  3. Switch compressor on, for this select ECON mode on A/C control head -E87- (indicator light in ECON button does not light up).
  4. Select temperature mode "Lo" (for driver's and passenger's side) on A/C Control Head -E87-.
  5. Select air flow direction on A/C Control Head -E87- to "air from dash panel vents"
  6. Select "Read Measuring Value Block" function 08, display group "001". See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  7. Check indication in display fields: A duty cycle greater than 30% is displayed in display field "2" (compressor is switched on, A/C Compressor Regulator Valve -N280- is activated or compressor is being driven via the A/C Clutch -N25-). A current greater than 0.3 A is displayed in display field "1" (current flows via A/C Compressor Regulator Valve -N280-, compressor is switched on) in vehicles with a compressor with A/C Compressor Regulator Valve -N280- In vehicles with a compressor with A/C Clutch -N25-, compressor is driven. A current greater than 0.1 A is displayed in display field "1", depending on version of A/C Control Head -E87- (current flows via A/C Clutch Relay -J44-, compressor is driven via the A/C Clutch -N25-). The shown pressure in display field "4" rises above the value with the compressor switched on.

Note. If display field "1" shows no or too little current on vehicles with A/C Compressor Regulator Valve -N280-, check: A/C Control Head -E87- activates A/C Compressor Regulator Valve -N280- so that the air temperature after evaporator reaches the specified value (approx. 2 to 5 C). A value greater than 75 % (0.55A) is displayed after vehicle start, depending on measured temperature, engine speed and vehicle electrical supply. As soon as the temperature measured by Evaporator Vent Temperature Sensor -G263- approaches the specified value, the activation is decreased and therefore compressor performance is reduced. The activation of A/C Compressor Regulator Valve -N280-. See Electrical Testing, TEST STEP 5 TO 9 , test step 6" In vehicles with a compressor with A/C Clutch -N25-, compressor is not being driven, check: The activation of A/C Clutch Relay -J44-. See Electrical Testing, TEST STEP 5 TO 9 , test step 7". If the shown pressure in display field "4" does not change and the activation of the compressor is OK (display field "1" and "2"), the refrigerant circuit has a malfunction. Determine and eliminate the cause.

  1. Press button for "air recirculation" (symbol for "air recirculation" mode button is lit up).
  2. Increase engine speed to 2000 RPM (timed period begins). Continuation of test
  3. On vehicle with compressor using A/C Compressor Regulator Valve -N280-. See «NOTES FOR TEST STEP 27»(/audi/a6/c5-2001-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25-removing) .
  4. On vehicles with compressor with A/C Clutch -N25-, see «A/C SYSTEM, CHECKING AND TESTING»(/audi/a6/c5-2001-2004/remont/automatic-hvac-system/#air-conditioning) .

Scheme 83

Scheme 83: Continuation for vehicles with compressor using A/C Compressor Regulator Valve -N280
Scheme 83: Continuation for vehicles with compressor using A/C Compressor Regulator Valve -N280
  1. Initiate "Read Measuring Value Block" function 08, and select display group "010" for vehicles from model year 2002. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  2. Compare displayed measuring value (of Evaporator V Temperature Sensor -G263-) in display field "1" with values in diagram.
  1. Measured air temperature of Evaporator Vent Temperature Sensor -G263
  2. Ambient temperature
  3. Permissible tolerance

Depending on the ambient temperature, the measured air temperature should be after 5 minutes within the shown tolerance range.

Note. If the required values are not attained, check the measuring value of Evaporator Vent Temperature Sensor -G263-, compare shown measuring values in display group "010" display field "1" and display group "009" display fields "3"and "4" with each other. If the measuring value in both display fields "3" or "4" deviates only slightly from the measuring value in display group "010", Carry out "Identifying malfunctions if specified values are not obtained". See IDENTIFYING MALFUNCTIONS IF SPECIFIED VALUES ARE NOT OBTAINED . If the measuring value of Evaporator Vent Temperature Sensor -G263- is greater than Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151-, check -G263- for correct installation and carry out electrical testing for this sensor. See MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002) . Also see Electrical testing, TEST STEP 1 TO 4 , test step 2. The operation of the air conditioning is recognizable, for example, the refrigerant pipe on the low pressure side (big line) cools off.

If the measuring value of Evaporator Vent Temperature Sensor -G263- is OK (and therefore the cooling performance of the air conditioning system).

  1. Compare the measuring value (of Evaporator Vent Temperature Sensor -G263-) in display group "010" display field 1 with the measuring values of display group "009" display fields "3" and "4" (-G150- and -G151-).

After 5 minutes, the measuring values in display group "009" display field "3" and "4" can be maximum 3 L C greater than the value in display field "1" of display group "010" (of Evaporator Vent Temperature Sensor -G263-).

Note. If the required values are not obtained, compare displayed measuring values in display group "009" display fields "3" and "4" with each other: If the measuring value in one the two display fields "3" or "4" OK. Check positioning motor for temperature flap on the side where the measuring value is not OK (Actuator for temperature flap left -V158- or Actuator for temperature flap right -V159-). See electrical testing, TEST STEP 1 TO 4 , test step 2. If the measuring value in display group "009" display fields "3" or "4" lower than the measuring value in display group "010" display field "1", check Evaporator Vent Temperature Sensor -G263-, Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151- for correct installation and their electrical connections for contact resistance, if necessary replace faulty sensor. If no malfunction is detected on -G150- and -G151-, as well as on -V158- and -V159-, carry out "Identifying malfunction at temperature raise after evaporator". See IDENTIFYING MALFUNCTIONS AT TEMPERATURE INCREASE BEHIND CONDENSER . The air temperature of the center dash panel vents can be measured e.g. using the VAG 1362 mini tester. The measuring value of Sender for outlet temperature, floor outlet -G192- is shown in display group "009" display field "1". This sensor shows an incorrect value, because in AUTO mode most of the air flow is directed to the dash panel vents. By pressing the "Air to footwell" button, this sensor can also be checked in this test.

Scheme 84

Scheme 84: Identifying malfunctions if specified values are not obtained
Scheme 84: Identifying malfunctions if specified values are not obtained
  1. For read measuring value block information, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08) . For vehicles from model year 2002, see «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  2. To check and erase DTC memory in A/C system, see «CHECK DTC MEMORY (FUNCTION 02)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and «ERASE DTC MEMORY (FUNCTION 05) AND END OUTPUT (FUNCTION 06)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .

Scheme 85

Scheme 85: Continuation of test - Pressure in refrigerant circuit increases
Scheme 85: Continuation of test - Pressure in refrigerant circuit increases
  1. For read measuring value block information, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08) . For vehicles from model year 2002, see «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
  2. To check activation of Coolant Fan -V7-, carry out «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a6/c5-2001-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm) .