SELF-DIAGNOSTICS
Note. Scan Tool (VAG 1551 or VAG1552) must be used to make full use of the system's self-diagnostic capabilities.
A/C-heater control panel receives input information from various electrical and electronic sensors. This information is processed by control panel according to specified values. Corresponding output signals are provided that control electrical actuators. Control panel is controlled by an internal microprocessor with On-Board Diagnostic (OBD) capability. If faults are detected, Diagnostic Trouble Codes (DTCs) are stored in DTC memory. Stored DTCs are identified using either VAG1551 or 1552 scan tool.
If a fault exists for a certain time, it is stored as a STATIC FAULT. If a static fault is no longer present, it is stored as a SPORADIC FAULT and the reference "SP" appears on the upper right of scan tool display or print out. Before replacing a component suspected of malfunctioning, check all related wiring, connections, harness connectors and ground connections using wiring diagram. Output Diagnostic Test Mode (DTM), Basic Setting, A/C control panel identification and coding functions are also possible.
RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES
Note. DTC output is possible only if ignition is on or engine is operating and engine speed is less than 3000 RPM (if engine speed is higher, output is possible only for a limited time or is terminated).
- Ensure battery is fully charged. Ensure all fuses are okay. Ensure ground connections at engine and transmission are clean and tight. Locate Data Link Connector (DLC), just left of steering column. Turn ignition off. Using Cable (VAG 1551/3), connect Scan Tool (VAG 1551 or 1552) to DLC.
- To check DTC memory press buttons "0" and "8" to select A/C HEATING ELECTRONICS function (address word 08). Advance program until SELECT FUNCTION XX appears on display. Turn scan tool printer on by pressing PRINT button (indicator light in button illuminates).
- Press buttons "0" and "2" to select CHECK DTC MEMORY. Press "Q" button to confirm input. Number of stored DTCs is displayed press right arrow button. If NO DTC RECOGNIZED is displayed, program returns to starting position after right arrow button is pressed.
- Two displays will alternately appear on scan tool. If necessary, press right arrow button on scan tool to move through program sequence. Press PRINT button to turn on scan tool printer. Turn on ignition or start engine. Press AUTO button. Press "1" button to select RAPID DATA TRANSFER function.
- With RAPID DATA TRANSFER displayed on scan tool, press "0" and "8" buttons to select A/C HEATING ELECTRONICS function. Press "Q" button to enter input. If CONTROL MODULE DOES NOT ANSWER or K WIRE NOT SWITCHING TO B+ is displayed, press HELP button to print out a list of possible causes. If NO SIGNAL FROM CONTROL MODULE is displayed, check DLC wiring for battery voltage and ground.
- If ERROR IN COMMUNICATION LINK is displayed at the beginning or during OBD program, malfunctions have occurred and data transfer is no longer possible between scan tool and A/C-heater control panel. Repair any scan tool or wiring malfunctions. Check voltage supply and ground circuits to A/C compressor clutch control module. After repairing problem, press "0" and "8" buttons to select A/C HEATING ELECTRONICS function. Press "Q" button to enter input.
- Scan tool should display SCAN TOOL SENDS ADDRESS WORD 08, then A/C control module identification, software version, and coding version should be displayed. A list of diagnostic functions can be printed out by pressing HELP button. See «DIAGNOSTIC FUNCTIONS»(ref-12058-S01966728482000120700000) table.
- Press right arrow button on scan tool until RAPID DATA TRANSFER is displayed on scan tool. When SELECT FUNCTION XX is displayed, press "0" and "2" buttons to select INTERROGATE DTC MEMORY function. Press "Q" button to enter input.
- An X DTC RECOGNIZED (number of DTCs stored) or NO DTC RECOGNIZED message will be displayed. Press right arrow button. Diagnostic trouble codes, if any, will be displayed and printed one after another. See «DTC IDENTIFICATION»(ref-12058-S08924981542000120700000) table. After last DTC has been displayed, turn ignition off. See appropriate DTC test.
- Repair A/C system malfunctions (if any). After repairs, test drive vehicle once more. Check for diagnostic trouble codes once again. If A/C compressor clutch does not engage, even though no DTC was recognized, perform MEASURING VALUE BLOCK function and OUTPUT DIAGNOSTIC TEST MODE.
| Function (1) | Description |
|---|
| 01 | Checking A/C-Heater Control Panel Versions |
| 02 | Checking DTC Memory |
| 03 (2) | Output Diagnostic Test Mode |
| 04 (3) | Basic Setting |
| 05 | Erasing DTC Memory |
| 06 | Ending Output |
| 07 (4) | Coding A/C-Heater Control Panel |
| 08 (5) | Reading Measuring Value Block |
| (1) To select diagnostic function, press appropriate buttons on scan tester when SELECT FUNCTION XX is displayed (i.e., press "0" and "2" buttons to select function 02). (2) See OUTPUT DIAGNOSTIC TEST MODE . (3) See BASIC SETTING . (4) See A/C-HEATER CONTROL PANEL CODING . (5) See READ MEASURING VALUE BLOCK . |
| (1) | To select diagnostic function, press appropriate buttons on scan tester when SELECT FUNCTION XX is displayed (i.e., press "0" and "2" buttons to select function 02). |
| (2) | See OUTPUT DIAGNOSTIC TEST MODE . |
| (4) | See A/C-HEATER CONTROL PANEL CODING . |
| (5) | See READ MEASURING VALUE BLOCK . |
| DTC | Probable Cause |
|---|
| 00000 | No DTC Recognized |
| 00532 | Supply Voltage Too Low |
| 00600 | Temperature Regulator Flap Motor Position Sensor |
| 00601 | Central Flap Motor Position Sensor |
| 00602 | Footwell/Defroster Motor Position Sensor |
| 00603 | Footwell/Defroster Flap Motor |
| 00604 | Back Pressure Flap Motor Position Sensor |
| 00625 | Road Speed Signal |
| 00779 | Outside Air Temperature Sensor |
| 00785 | Instrument Panel Interior Temperature Sensor |
| 00787 | Fresh Air Intake Duct Temperature Sensor |
| 00792 | A/C Pressure Switch |
| 00796 | Interior Temperature Sensor Fan |
| 00797 | Sunlight Photo Sensor |
| 01044 | A/C-Heater Control Panel Incorrectly Coded |
| 01087 | Basic Setting Not Performed |
| 01206 | Signal For Time Span Ignition Off (Incorrect Signal) |
| 01271 | Temperature Regulator Flap Motor |
| 01272 | Central Air Flap Motor |
| 01273 | Fresh Air Blower |
| 01274 | Airflow Flap Motor |
| 01296 | Center Outlet Temperature Sensor |
| 01297 | Floor Outlet Temperature Sensor |
| 01582 | Coolant Temperature Signal |
| 65535 | A/C-Heater Control Panel Malfunction |
OUTPUT DIAGNOSTIC TEST MODE
| CAUTION | Keep clear of coolant fan during testing. Coolant fan may activate unexpectedly. |
Note. During output diagnostic test mode, vehicle must not be moved and engine speed must be less than 3000 RPM. The A/C-heater control system is switched off and both A/C-heater control panel displays are actuated.
- Start engine. Press AUTO button to switch on A/C compressor. Adjust airflow to center instrument panel outlets. Check Diagnostic Trouble Code (DTC) memory. See «RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES»(ref-12058-S00600530252000120700000) under SELF-DIAGNOSTICS. Press PRINT button to turn on scan tool printer.
- Ensure scan tool is in A/C HEATING ELECTRONICS function. With RAPID DATA TRANSFER displayed on scan tool, press "0" and "3" buttons to select OUTPUT DIAGNOSTIC TEST MODE function. Press "Q" button to confirm input.
- Use right arrow button to advance through component checks. See «OUTPUT DIAGNOSTIC TEST MODE»(ref-12058-S23367517672000120700000) table. If FUNCTION UNKNOWN OR CANNOT BE CARRIED OUT AT THE MOMENT! is displayed at start of test, press button and re-enter test. If FUNCTION UNKNOWN OR CANNOT BE CARRIED OUT AT THE MOMENT! is still displayed, read measuring value block. See «READ MEASURING VALUE BLOCK»(ref-12058-S13477672122000120700000) .
- Output diagnostic test mode can be ended by pressing "C" button. When test is complete, FUNCTION UNKNOWN OR CANNOT BE CARRIED OUT AT THE MOMENT! will be displayed. After ending output diagnostic test mode, check DTC memory. See «RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES»(ref-12058-S00600530252000120700000) under SELF-DIAGNOSTICS. Press right arrow button to end procedure.
| Application | Function | Probable Cause Or Defect |
|---|
| A/C Clutch (1) | (2) Control Voltage Switches 0-12 Volts Every 2 Seconds | Circuits Or Components |
| Fresh Air Blower | (3) Fresh Air Blower Runs For 2 Seconds | Binding, Bad Ground, Or Components |
| Coolant Fan | Stage No. 1 Switched On/Off Every 5 Seconds | Circuits Or Components |
| Fresh/Recirc. Air Flap Valve | Switches Fresh/Recirc. Every 5 Seconds | Vacuum Supply, Circuits, Or Components |
| Temp. Regulator Flap Motor | (4) Moves From Stop To Stop | Binding, Circuits, Or Components |
| Central Air Flap Motor | (5) Moves From Stop To Stop | Binding, Circuits, Or Components |
| Footwell/Defroster Flap Motor | (6) Moves From Stop To Stop | Binding, Circuits, Or Components |
| Airflow Flap Motor | Moves From Stop To Stop | Binding, Circuits, Or Components |
| Interior Temp. Sensor Fan | (7) Fan Switched On/Off Every 5 Seconds | Restriction In Slot Or Intake Hose, Circuits, Or Components |
| Segment Test | Control Panel Segments Switched On/Off Every 3 Seconds | Replace Bulbs or A/C-Heater Control Panel |
| Outside Air Temp. Display | Temp. Display In Auto Check System Begins Counting Up at 3 Second Intervals | Circuits Or Auto Check System, If Equipped |
| (1) A/C clutch will not be actuated if certain A/C compressor switch-off conditions exist. See A/C COMPRESSOR SWITCH-OFF CONDITIONS (DISPLAY GROUP NO. 1) table. (2) A/C clutch should also click every 2 seconds. To verify voltage at A/C-heater control panel, switch compressor on and off using ECON button while reading measured value block of Engine Control Module (ECM). (3) Fresh air blower will operate for 2 seconds when 0, 3, 6, 9, 12, 15, then 0 volts is applied using scan tool. Keep clear of coolant fan. Pressing right arrow will activate coolant fan. (4) Wait until temperature regulator flap is in heat position before pressing right arrow button to continue test. (5) Wait until central air flap is in footwell/defroster position before pressing right arrow button to continue test. Close all instrument panel air outlets. (6) Wait until footwell/defroster flap is in defrost position before pressing right arrow button to continue test. (7) Verify operation by blowing smoke over intake slot on center of instrument panel or hold tissue paper over intake slot. |
| (1) | A/C clutch will not be actuated if certain A/C compressor switch-off conditions exist. See A/C COMPRESSOR SWITCH-OFF CONDITIONS (DISPLAY GROUP NO. 1) table. |
| (2) | A/C clutch should also click every 2 seconds. To verify voltage at A/C-heater control panel, switch compressor on and off using ECON button while reading measured value block of Engine Control Module (ECM). |
| (3) | Fresh air blower will operate for 2 seconds when 0, 3, 6, 9, 12, 15, then 0 volts is applied using scan tool. Keep clear of coolant fan. Pressing right arrow will activate coolant fan. |
| (4) | Wait until temperature regulator flap is in heat position before pressing right arrow button to continue test. |
| (5) | Wait until central air flap is in footwell/defroster position before pressing right arrow button to continue test. Close all instrument panel air outlets. |
| (6) | Wait until footwell/defroster flap is in defrost position before pressing right arrow button to continue test. |
| (7) | Verify operation by blowing smoke over intake slot on center of instrument panel or hold tissue paper over intake slot. |
OUTPUT DIAGNOSTIC TEST MODE
| Code No. (Compressor Condition) | Affected Circuit/Cause |
|---|
| 0 (Compressor On) (1) | Switch-Off Condition Not Recognized |
| 1 (Compressor Off) | (2) Open Circuit Between High-Pressure Cut-Out Switch & A/C-Heater Control Panel Or Open High-Pressure Cut-Out Switch |
| 3 (Compressor Off) (3) | (2) Open Circuit Between Low-Pressure Switch & A/C-Heater Control Panel Or Open Low-Pressure Switch |
| 5 (Compressor Off) | (4) Engine Speed Signal Not Recognized Or Engine Speed Less Than 300 RPM |
| 6 (Compressor Off) | (5) A/C Compressor Switched Off At ECON Button |
| 7 (Compressor Off) | (5) A/C Compressor Switched Off At "-" Button For Fresh Air Blower Speed |
| 8 (Compressor Off) | (6) Incorrect Values Supplied By Outside Air Temperature Sensor Or Fresh Air Intake Duct Temperature Sensor, Or Outside Ambient Temperature Less Than 36°F (2°C) |
| 10 (Compressor Off) | Supply Voltage For A/C Clutch Less Than 9.5 Volts |
| 11 (Compressor Off) | Short To Ground Between Instrument Cluster & A/C-Heater Control Panel, Or Excessive Engine Temperature |
| 12 (Compressor Off) | (1) ECM Or Transmission Control Module (TCM) Has Switched Off A/C Compressor |
| 13 (Compressor Off) | (7) A/C Compressor Cut-In Time Lag (About 10 Seconds) At Engine Speeds Higher Than 6000 RPM |
| 14 (Compressor Off) | (8) High-Pressure Cut-Out Switch Has Switched On & Off 30 Times During Present Driving Period |
| (1) If A/C compressor does not come on, perform OUTPUT DIAGNOSTIC TEST MODE . (2) Test switch. See A/C PRESSURE SWITCH, A/C COMPRESSOR SIGNAL, ENGINE TEMP. SIGNAL & INTERIOR TEMP. SENSOR FAN under SYSTEM TESTS. Check A/C system pressures. See A/C SYSTEM PERFORMANCE under SYSTEM TESTS. (3) If voltage at A/C-heater control panel is less than 6 volts, code No. 3 may set. (4) Check for open circuit between instrument cluster, ECM, and A/C-Heater control panel. Check for unusable engine speed signal supplied by ECM or instrument cluster. (5) Press AUTO button to activate compressor. (6) Test outside air temperature sensor or fresh air intake duct temperature sensor. See TEMPERATURE SENSORS under SYSTEM TESTS. (7) No service is necessary. (8) Check for poor connection or open circuit between high-pressure cut-out switch and A/C-heater control panel. Test high-pressure cut-out switch. See A/C PRESSURE SWITCH, A/C COMPRESSOR SIGNAL, ENGINE TEMP. SIGNAL & INTERIOR TEMP. SENSOR FAN under SYSTEM TESTS. Check A/C system pressures. See A/C SYSTEM PERFORMANCE under SYSTEM TESTS. |
| (1) | If A/C compressor does not come on, perform OUTPUT DIAGNOSTIC TEST MODE . |
| (2) | Test switch. See A/C PRESSURE SWITCH, A/C COMPRESSOR SIGNAL, ENGINE TEMP. SIGNAL & INTERIOR TEMP. SENSOR FAN under SYSTEM TESTS. Check A/C system pressures. See A/C SYSTEM PERFORMANCE under SYSTEM TESTS. |
| (3) | If voltage at A/C-heater control panel is less than 6 volts, code No. 3 may set. |
| (4) | Check for open circuit between instrument cluster, ECM, and A/C-Heater control panel. Check for unusable engine speed signal supplied by ECM or instrument cluster. |
| (5) | Press AUTO button to activate compressor. |
| (6) | Test outside air temperature sensor or fresh air intake duct temperature sensor. See TEMPERATURE SENSORS under SYSTEM TESTS. |
| (7) | No service is necessary. |
| (8) | Check for poor connection or open circuit between high-pressure cut-out switch and A/C-heater control panel. Test high-pressure cut-out switch. See A/C PRESSURE SWITCH, A/C COMPRESSOR SIGNAL, ENGINE TEMP. SIGNAL & INTERIOR TEMP. SENSOR FAN under SYSTEM TESTS. Check A/C system pressures. See A/C SYSTEM PERFORMANCE under SYSTEM TESTS. |
A/C COMPRESSOR SWITCH-OFF CONDITIONS (DISPLAY GROUP NO. 01)
| Display Field | (1) Specified Values |
|---|
| 1 | (2) Readout Should Be More Than 5, But Less Than 240 |
| 2 | (3) Readout 5-240 |
| 3 | (4) Readout Should Be More Than 5, But Less Than 50 |
| 4 | (5) Readout Should Be More Than 180, But Less Than 240 |
| (1) Actual feedback values between 5-50 and between 180-240 are specified tolerance ranges for flap motors and flap stops as input to A/C-heater control panel. (2) Actual motor position sensor feedback value. Maximum difference in range between 50-180 is 3 from feedback value. If feedback value is less than 5 (indicating a short circuit) or greater than 240 (indicating an open circuit) check circuits between control panel and motor. (3) Specified feedback value for flap motor position sensor as calculated by A/C-heater control panel. (4) Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor at FULL HEATING position temperature flap (airflow is directed through heater core). (5) Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in FULL COOLING position (airflow is directed to by-pass heater core). |
| (1) | Actual feedback values between 5-50 and between 180-240 are specified tolerance ranges for flap motors and flap stops as input to A/C-heater control panel. |
| (2) | Actual motor position sensor feedback value. Maximum difference in range between 50-180 is 3 from feedback value. If feedback value is less than 5 (indicating a short circuit) or greater than 240 (indicating an open circuit) check circuits between control panel and motor. |
| (3) | Specified feedback value for flap motor position sensor as calculated by A/C-heater control panel. |
| (4) | Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor at FULL HEATING position temperature flap (airflow is directed through heater core). |
| (5) | Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in FULL COOLING position (airflow is directed to by-pass heater core). |
TEMPERATURE REGULATOR FLAP MOTOR (DISPLAY GROUP NO. 02)
| Display Field | Specified Values |
|---|
| 1 | (1) Readout Should Be More Than 25, But Less Than 250 |
| 2 | (2) Readout Should Be More Than 25, But Less Than 250 |
| 3 | (3) Readout Should Be More Than 25, But Less Than 75 |
| 4 | (4) Readout Should Be More Than 200, But Less Than 250 |
| (1) Actual motor position sensor feedback value. Maximum difference in range between 75-200 is 3 from feedback value. If feedback value is less than 25 (indicating a short circuit) or greater than 250 (indicating an open circuit) check circuits between control panel and motor. (2) Specified feedback value for flap motor position sensor as calculated by A/C-heater control panel. (3) Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in BOTTOM STOP position (airflow is directed to footwell/defroster flap). (4) Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in TOP STOP position (airflow is directed through instrument panel air outlets). |
| (1) | Actual motor position sensor feedback value. Maximum difference in range between 75-200 is 3 from feedback value. If feedback value is less than 25 (indicating a short circuit) or greater than 250 (indicating an open circuit) check circuits between control panel and motor. |
| (2) | Specified feedback value for flap motor position sensor as calculated by A/C-heater control panel. |
| (3) | Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in BOTTOM STOP position (airflow is directed to footwell/defroster flap). |
| (4) | Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in TOP STOP position (airflow is directed through instrument panel air outlets). |
CENTRAL FLAP MOTOR (DISPLAY GROUP NO. 03)
| Display Field | Specified Values |
|---|
| 1 | (1) Readout Should Be More Than 25, But Less Than 250 |
| 2 | (2) Readout 25-250 |
| 3 | (3) Readout Should Be More Than 25, But Less Than 75 |
| 4 | (4) Readout Should Be More Than 200, But Less Than 250 |
| (1) Actual motor position sensor feedback value. Maximum difference in range between 75-200 is 3 from feedback value. If feedback value is less than 25 (indicating a short circuit) or greater than 250 (indicating an open circuit) check circuits between control panel and motor. (2) Specified feedback value for flap motor position sensor as calculated by A/C-heater control panel. (3) Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in BOTTOM STOP position (airflow is directed to instrument panel defroster outlets). (4) Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in TOP STOP position (airflow is directed to footwell outlets). |
| (1) | Actual motor position sensor feedback value. Maximum difference in range between 75-200 is 3 from feedback value. If feedback value is less than 25 (indicating a short circuit) or greater than 250 (indicating an open circuit) check circuits between control panel and motor. |
| (2) | Specified feedback value for flap motor position sensor as calculated by A/C-heater control panel. |
| (3) | Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in BOTTOM STOP position (airflow is directed to instrument panel defroster outlets). |
| (4) | Value of flap motor position sensor calculated during basic setting and stored in A/C-heater control panel with motor in TOP STOP position (airflow is directed to footwell outlets). |
FOOTWELL/DEFROSTER FLAP MOTOR (DISPLAY GROUP 04)
| Display Field | Specified Values |
|---|
| 1 | (1) Readout Should Be More Than 5, But Less Than 250 |
| 2 | (2) Readout 5-250 |
| 3 | (3) Readout Should Be More Than 5, But Less Than 60 |
| 4 | (4) Readout Should Be More Than 190, But Less Than 250 |
| (1) Actual back pressure flap motor position sensor feedback value. Maximum difference in range more than 60, but less than 190 is 3 from feedback value. If feedback value is less than 25 (indicating a short circuit) or greater than 250 (indicating an open circuit) check circuits between control panel and motor. (2) Specified feedback value for potentiometer as calculated by A/C-heater control panel. (3) Value of potentiometer calculated during basic setting and stored in A/C-heater control panel with motor in BOTTOM STOP position (air flow flap in air intake area of evaporator closed, A/C in recirculating mode). (4) Value of potentiometer calculated during basic setting and stored in A/C-heater control panel with motor in TOP STOP position (air flow flap in air intake area of evaporator open, A/C in fresh air mode). |
| (1) | Actual back pressure flap motor position sensor feedback value. Maximum difference in range more than 60, but less than 190 is 3 from feedback value. If feedback value is less than 25 (indicating a short circuit) or greater than 250 (indicating an open circuit) check circuits between control panel and motor. |
| (2) | Specified feedback value for potentiometer as calculated by A/C-heater control panel. |
| (3) | Value of potentiometer calculated during basic setting and stored in A/C-heater control panel with motor in BOTTOM STOP position (air flow flap in air intake area of evaporator closed, A/C in recirculating mode). |
| (4) | Value of potentiometer calculated during basic setting and stored in A/C-heater control panel with motor in TOP STOP position (air flow flap in air intake area of evaporator open, A/C in fresh air mode). |
AIRFLOW FLAP MOTOR (DISPLAY GROUP 05)
| Display Field | Specified Value |
|---|
| 1 | (1) (2) |
| 2 | (3) Measured Value Of Sensor In °F (°C) |
| 3 | (1) (4) Measured Value Of Sensor In °F (°C) |
| 4 | (5) 0.5-4.5 Volts Depending On Sunlight Intensity |
| (1) Display field 1 is lower of two measured outside temperatures from fresh air intake duct temperature sensor and outside air temperature sensor shown in display fields 2 and 3. Readout is stored for up to 4 hours after turning ignition off. Output supplied by a malfunctioning temperature sensor is suppressed by A/C-heater control panel and an internal computed value is used for control functions. (2) Calculated temperature for outside air temperature displayed on A/C-heater panel. (3) Fresh air intake duct temperature sensor. (4) Outside air temperature sensor. (5) Sunlight photo sensor. Readout is in percent between zero percent (4.5 volts) and 100 percent (0.5 volts). Readout for sunlight photo sensor can be checked using a suitable light source aimed at sensor. If approximately one volt (which corresponds to 90 percent of maximum sunlight penetration) is continuously displayed regardless of light intensity, check wiring to using wiring diagram. |
| (1) | Display field 1 is lower of two measured outside temperatures from fresh air intake duct temperature sensor and outside air temperature sensor shown in display fields 2 and 3. Readout is stored for up to 4 hours after turning ignition off. Output supplied by a malfunctioning temperature sensor is suppressed by A/C-heater control panel and an internal computed value is used for control functions. |
| (2) | Calculated temperature for outside air temperature displayed on A/C-heater panel. |
| (3) | Fresh air intake duct temperature sensor. |
| (4) | Outside air temperature sensor. |
| (5) | Sunlight photo sensor. Readout is in percent between zero percent (4.5 volts) and 100 percent (0.5 volts). Readout for sunlight photo sensor can be checked using a suitable light source aimed at sensor. If approximately one volt (which corresponds to 90 percent of maximum sunlight penetration) is continuously displayed regardless of light intensity, check wiring to using wiring diagram. |
AIR TEMPERATURE SENSORS & DISPLAY, & SUNLIGHT PHOTO SENSOR (DISPLAY GROUP 06)
| Display Field | Specified Values |
|---|
| 1 | (1) (2) Measured Value Of Sensor In °F (°C) |
| 2 | (3) Measured Value Of Sensor In °F (°C) |
| 3 | (1) (4) Measured Value Of Sensor In °F (°C) |
| 4 | (5) |
| (1) If differences exist between specified values, check A/C-heater control panel coding. See A/C-HEATER CONTROL PANEL CODING . Output supplied by a malfunctioning temperature sensor is suppressed by A/C-heater control panel and an internal computed value is used for control functions. (2) Center outlet temperature sensor. (3) Floor outlet temperature sensor. (4) A/C-heater control panel instrument panel interior temperature sensor. Interior temperature sensor installed in control panel with one display cannot be checked or replaced individually, if sensor is malfunctioning A/C-heater control panel must be replaced. (5) Coolant temperature signal from instrument cluster, for control of fresh air blower speed. Only coolant temperature signals more than 104°F (40°C) are used by A/C-heater control panel. With no coolant temperature signal (malfunction, open circuit etc.), 127°F (53°C) is displayed and an internal computed value is used for control functions. |
| (1) | If differences exist between specified values, check A/C-heater control panel coding. See A/C-HEATER CONTROL PANEL CODING . Output supplied by a malfunctioning temperature sensor is suppressed by A/C-heater control panel and an internal computed value is used for control functions. |
| (2) | Center outlet temperature sensor. |
| (3) | Floor outlet temperature sensor. |
| (4) | A/C-heater control panel instrument panel interior temperature sensor. Interior temperature sensor installed in control panel with one display cannot be checked or replaced individually, if sensor is malfunctioning A/C-heater control panel must be replaced. |
| (5) | Coolant temperature signal from instrument cluster, for control of fresh air blower speed. Only coolant temperature signals more than 104°F (40°C) are used by A/C-heater control panel. With no coolant temperature signal (malfunction, open circuit etc.), 127°F (53°C) is displayed and an internal computed value is used for control functions. |
MEASURED VALUE OF SENSORS FOR OUTLET TEMPERATURE & INTERIOR TEMPERATURE SENSOR (DISPLAY GROUP 07)
| Display Field | Specified Values |
|---|
| 1 | (1) Readout 0-12.5 Volts |
| 2 | (2) Less Than 0.7 Volt Different From Specified Voltage |
| 3 | (3) |
| 4 | (4) Readout is 0-100 Percent |
| (1) Specified voltage for fresh air blower calculated by A/C-heater control panel. (2) Actual voltage at fresh air blower. (3) Voltage measured for illumination of display elements. With parking lights off, approximately battery voltage should be present. With parking lights on, approximately 2-12.5 volts should be present. Voltage should change as instrument panel illumination dimmer switch is changed. (4) Voltage for illuminating A/C-heater control panel switch. Readout of 0-100 percent depends on setting of dimmer switch with ignition on. |
| (1) | Specified voltage for fresh air blower calculated by A/C-heater control panel. |
| (2) | Actual voltage at fresh air blower. |
| (3) | Voltage measured for illumination of display elements. With parking lights off, approximately battery voltage should be present. With parking lights on, approximately 2-12.5 volts should be present. Voltage should change as instrument panel illumination dimmer switch is changed. |
| (4) | Voltage for illuminating A/C-heater control panel switch. Readout of 0-100 percent depends on setting of dimmer switch with ignition on. |
VOLTAGE AT FRESH AIR BLOWER & ILLUMINATION OF DISPLAY ELEMENTS (DISPLAY GROUP 08)
| Display Field | Specified Values |
|---|
| 1 | Engine Speed In RPM |
| 2 | (1) Vehicle Speed In MPH (KM/H) |
| 3 | (2) Parking Lights ON Or OFF Signal |
| 4 | (3) Not Assigned |
| (1) If "0" is displayed, no speed signal has been recognized since ignition was turned on. If "1" is displayed, speed signal has been recognized at least once since ignition was turned on. (2) If "0" is displayed, indication is that the parking lights are off. Voltage measured at A/C-heater control panel connector terminal A6 (Gray/Green wire) is less than 5 volts. If "1" is displayed, indication is that the parking lights are on. Voltage measured at A/C-heater control panel connector terminal A6 (Gray/Green wire) is more than 5 volts. If A/C-heater control panel remains activated after ignition is turned off and "1" is displayed, check for a short to battery voltage between control panel connector terminal D1 and instrument cluster. (3) Position is not assigned, disregard readout. |
| (1) | If "0" is displayed, no speed signal has been recognized since ignition was turned on. If "1" is displayed, speed signal has been recognized at least once since ignition was turned on. |
| (2) | If "0" is displayed, indication is that the parking lights are off. Voltage measured at A/C-heater control panel connector terminal A6 (Gray/Green wire) is less than 5 volts. If "1" is displayed, indication is that the parking lights are on. Voltage measured at A/C-heater control panel connector terminal A6 (Gray/Green wire) is more than 5 volts. If A/C-heater control panel remains activated after ignition is turned off and "1" is displayed, check for a short to battery voltage between control panel connector terminal D1 and instrument cluster. |
| (3) | Position is not assigned, disregard readout. |
ENGINE SPEED & VEHICLE SPEED (DISPLAY GROUP 09)
| Display Field | Specified Values |
|---|
| 1 | (1) Engine Coolant Temperature Signal Processed By Instrument Cluster |
| 2 | (2) A/C Compressor Intervention |
| 3 | (3) A/C Pressure Switch |
| 4 | (4) Rear Window Defrost Activation |
| (1) If "0" is displayed, temperature switch is open. Coolant temperature is normal and voltage measured at A/C-heater control panel connector terminal A11 (Blue/Violet wire) is more than 5 volts. If "1" is displayed, temperature switch is closed. Coolant temperature is excessive and voltage measured at A/C-heater control panel connector terminal A11 (Blue/Violet wire) is less than 5 volts. If excessive coolant temperature code "1" is displayed, check wiring harness between control panel and instrument cluster. (2) If "0" is displayed, A/C compressor intervention output is open. Voltage measured at A/C-heater control panel connector terminal C12 (Black/Gray wire) is more than 5 volts. If "1" is displayed, A/C compressor intervention output is closed. Voltage measured at A/C-heater control panel connector terminal C12 (Black/Gray wire) is less than 5 volts. When A/C clutch is activated, output is closed and voltage is more than 5 volts. When A/C clutch is activated, if voltage decreases to less than 5 volts, A/C-heater control panel will deactivate A/C clutch. (3) If "1" is displayed, pressure switch is open. Voltage measured at A/C-heater control panel connector terminal C2 (Brown/Blue wire) is less than 2 volts. If "0" is displayed, pressure switch is closed. Voltage measured at A/C-heater control panel connector terminal C2 (Brown/Blue wire) is more than 2 volts. (4) If "0" is displayed, rear window defrost is off. If "1" is displayed, rear window defrost is on. |
| (1) | If "0" is displayed, temperature switch is open. Coolant temperature is normal and voltage measured at A/C-heater control panel connector terminal A11 (Blue/Violet wire) is more than 5 volts. If "1" is displayed, temperature switch is closed. Coolant temperature is excessive and voltage measured at A/C-heater control panel connector terminal A11 (Blue/Violet wire) is less than 5 volts. If excessive coolant temperature code "1" is displayed, check wiring harness between control panel and instrument cluster. |
| (2) | If "0" is displayed, A/C compressor intervention output is open. Voltage measured at A/C-heater control panel connector terminal C12 (Black/Gray wire) is more than 5 volts. If "1" is displayed, A/C compressor intervention output is closed. Voltage measured at A/C-heater control panel connector terminal C12 (Black/Gray wire) is less than 5 volts. When A/C clutch is activated, output is closed and voltage is more than 5 volts. When A/C clutch is activated, if voltage decreases to less than 5 volts, A/C-heater control panel will deactivate A/C clutch. |
| (3) | If "1" is displayed, pressure switch is open. Voltage measured at A/C-heater control panel connector terminal C2 (Brown/Blue wire) is less than 2 volts. If "0" is displayed, pressure switch is closed. Voltage measured at A/C-heater control panel connector terminal C2 (Brown/Blue wire) is more than 2 volts. |
| (4) | If "0" is displayed, rear window defrost is off. If "1" is displayed, rear window defrost is on. |
ENGINE COOLANT TEMPERATURE SWITCH, A/C COMPRESSOR CUT-IN, A/C HIGH PRESSURE SWITCH & REAR WINDOW DEFROST ACTIVATION (DISPLAY GROUP 10)
| Display Field | (1) Specified Value |
|---|
| 1 | Fourth To Last Compressor Cut-Off Condition |
| 2 | Third To Last Compressor Cut-Off Condition |
| 3 | Second To Last Compressor Cut-Off Condition |
| 4 | Last Compressor Cut-Off Condition |
| (1) Only compressor cut-off conditions that were effective for more than 20 seconds are stored. See A/C COMPRESSOR SWITCH-OFF CONDITIONS (DISPLAY GROUP NO. 01) . |
| (1) | Only compressor cut-off conditions that were effective for more than 20 seconds are stored. See A/C COMPRESSOR SWITCH-OFF CONDITIONS (DISPLAY GROUP NO. 01) . |
LAST 4 COMPRESSOR CUT-OFF CONDITIONS (DISPLAY GROUP 11)
| Display Field | Specified Value |
|---|
| 1 | (1) Idle Regulator ON/OFF |
| 2 | (2) Coolant Fan Activation Relay Stage 1 ON/OFF |
| 3 | Not Assigned |
| 4 | Not Assigned |
| (1) If "0" is displayed, idle regulator is off. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is less than 2 volts. If "1" is displayed, idle regulator is on. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is more than 2 volts. For idle regulator to activate, there cannot be any A/C compressor cut-off conditions present that would prevent A/C clutch activation. (2) If "0" is displayed, coolant fan activation relay first stage is off. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is more than 5 volts (fan off). If "1" is displayed, coolant fan activation relay first stage is on. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is less than 5 volts (fan on). A/C-heater control panel activates coolant fan first stage if there are no A/C compressor cut-off conditions present. |
| (1) | If "0" is displayed, idle regulator is off. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is less than 2 volts. If "1" is displayed, idle regulator is on. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is more than 2 volts. For idle regulator to activate, there cannot be any A/C compressor cut-off conditions present that would prevent A/C clutch activation. |
| (2) | If "0" is displayed, coolant fan activation relay first stage is off. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is more than 5 volts (fan off). If "1" is displayed, coolant fan activation relay first stage is on. Measured voltage at A/C-heater control panel connector terminal A2 (Black/Yellow wire) is less than 5 volts (fan on). A/C-heater control panel activates coolant fan first stage if there are no A/C compressor cut-off conditions present. |
IDLE RPM INCREASE, ACTIVATION COOLANT FAN, IGNITION KEY CODING (DISPLAY GROUP 12)
DTC 00000: NO DTC RECOGNIZED
System is operating properly.
DTC 00532: SUPPLY VOLTAGE TOO LOW
Note. If voltage at A/C-heater control panel connector drops to less than 9.5 volts, A/C compressor will switch off for a minimum of 25 seconds. A/C compressor will switch on again when voltage exceeds 10.8 volts.
DTC 00600: TEMPERATURE REGULATOR FLAP MOTOR POSITION SENSOR
Note. When fault exists at temperature regulator flap motor position sensor, flap motor can be set manually by pressing + or - buttons for temperature selection.
DTC 00601: CENTRAL FLAP MOTOR POSITION SENSOR
Note. If travel limit is exceeded, fault will only be recognized during basic setting procedure.
Note. If travel limit is exceeded, fault will only be recognized during basic setting procedure.
DTC 00604: BACK PRESSURE FLAP MOTOR POSITION SENSOR
Note. If travel limit is exceeded, fault will only be recognized during basic setting procedure.
DTC 00792: A/C PRESSURE SWITCH
Note. When A/C pressure switch terminals No. 1 and 2 open, excess refrigerant pressure is recognized by A/C-heater control panel and a DTC will be stored. If measured outside temperature is between 32-122°F (0-50°C) and switch terminals No. 1 and 2 remain open for longer than 30 seconds, control panel switches over from excessive pressure to low pressure switch function. When pressure switch has opened 30 times during a driving period, A/C compressor will be turned off. Compressor can be turned on again by pressing ECON button or by turning ignition off and then on. If this malfunction occurs frequently, compressor can only be turned on after erasing DTC memory.
DTC 01206: SIGNAL FOR TIME SPAN IGNITION OFF (INCORRECT SIGNAL)
Note. If A/C-heater control panel is unable to determine duration of time when ignition is off (standing time), DTC 01206 is loaded into memory. The A/C-heater control panel will default to a standing time greater than 4 hours. Actual measured values of outside temperature sensor are then used as outside and engine temperature inputs for A/C system control. When heating mode is selected under these conditions, fresh air blower has a delayed start (even when actual standing time is less than 4 hours and engine is warm). Outside air temperature display may also indicate incorrect outside temperature values.
Test Equipment Hook-Up
Note. Test Box (VAG 1598) must not be connected to A/C-heater control panel connector when using Scan Tool (VAG 1551).
- Ensure battery voltage is okay. Ensure engine and transmission grounds are okay. Ensure fuses No. 42 (40-amp), No. 51 (5-amp), No. 225 (30-amp), and No. 15 (10-amp) are okay.
- Turn ignition off. Remove A/C-heater control panel, and disconnect electrical connectors. (Scheme 6) While performing tests, DO NOT connect adapter harnesses to A/C-heater control panel, or A/C-heater control panel will be damaged.
- Connect Adapter Cable (VAG 1598/11 or 12) to appropriate A/C-heater control panel connector. For Adapter Cable (VAG 1598/12), terminals are identical to A/C-heater control panel terminals. For Adapter Cable (VAG 1598/11), adapter cable terminal numbers and A/C-heater control panel wiring harness terminal numbers are not the same. Connector "A" terminals No. 1-12 are identified as terminals No. 41-52 on adapter cable. Connector "B" terminals No. 1-20 are identified as terminals No. 21-40. Connector "C" and "D" terminal No. 1-16 are identified as terminals No. 1-16.
| CAUTION | Switch Digital Volt-Ohmmeter (DVOM) to correct measuring range before connecting test leads, or electronic components may be damaged. |
Note. When Adapter Cable (VAG 1598/11) is connected, no ground connection exists. Use external ground source or second adapter cable during electrical testing. When Adapter Cable (VAG 1598/12) is connected, ground exists at terminals No. 14 and 15.
Scheme 6
Test Procedure
Note. Ground connection for test procedure is available at connector "D" terminal No. 14 or 15.
- Using Adapter Cable (VAG 1598/12) and DVOM in 20-volt range, check voltage between adapter cable terminals No. 9 and 14 with ignition on. Ensure battery voltage exists. If battery voltage does not exist, check Black/Red wire between fuse block and A/C-heater control panel. Also check Brown wires between A/C-heater control panel and ground. See «WIRING DIAGRAMS»(ref-12058-S15104582522000120700000) .
- Check voltage between Adapter Cable (VAG 1598/12) terminals No. 9 and 15 with ignition on. Ensure battery voltage exists. If battery voltage does not exist, check Brown wires between A/C-heater control panel and ground.
- Turn ignition off. Using Adapter Cable (VAG 1598/11) and DVOM in 200-ohm range, check resistance of circuit between ground and adapter cable terminals No. 49 and 52. Ensure resistance for each circuit is less than 20 ohms. Repair ground circuit(s) if necessary.
- Connect Adapter Cable (VAG 1598/11) to A/C-heater control panel. Connect LED Voltage Tester (VAG 1527B) between adapter cable terminals No. 15 and 33. Turn ignition on. LED should illuminate. If LED does not illuminate, repair open or short. See «WIRING DIAGRAMS»(ref-12058-S15104582522000120700000) .
- With Adapter Cable (VAG 1598/11) and LED Voltage Tester (VAG 1527B) still connected, start engine and allow to idle. LED should flicker briefly (time signal) and then illuminate. If LED does not flicker, check signal from instrument cluster. Repair as necessary.
- Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 7 and ground with ignition on and parking lights on. Voltage should be 0-12 volts depending on illumination rheostat setting (instrument panel illumination dimmer switch). If voltage is not as specified, repair open or short in Gray/Blue wire.
- Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 7 and ground with ignition on and parking lights off. Voltage should be approximately zero volts depending on illumination rheostat setting (instrument panel illumination dimmer switch). If voltage is not as specified, repair short to battery voltage in Gray/Blue wire.
- Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 45 and ground with ignition on and parking lights on. Voltage should be 0-12 volts depending on square-wave signal from instrument cluster (DVOM will indicate average voltage). Brightness of A/C-heater control panel display is determined by length of activation. If voltage is not as specified, repair open or short in Gray/Blue wire. See «WIRING DIAGRAMS»(ref-12058-S15104582522000120700000) .
- Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 45 and ground with ignition on and parking lights off. Voltage should be approximately 0-12 volts depending on square-wave signal from instrument cluster (DVOM will indicate average voltage). Brightness of A/C-heater control panel display is determined by length of activation. If voltage is not as specified, repair short to battery voltage in Gray/Blue wire.
- Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 46 and ground with ignition on and parking lights on. Voltage should be approximately battery voltage. If voltage is not as specified, repair open or short in A/C-heater control panel ground circuits.
- Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 46 and ground with ignition on and parking lights off. Voltage should be less than 2 volts. If voltage is not as specified, repair open or short in A/C-heater control panel ground circuits.
- Using Adapter Cable (VAG 1598/12) and DVOM in 20-volt range, check voltage between adapter cable terminals No. 8 and 14 with ignition on. Voltage should be approximately battery voltage. If voltage is not as specified, repair power supply or ground circuits. See «WIRING DIAGRAMS»(ref-12058-S15104582522000120700000) .
