Heating Air Conditioning: Diagnosis Audi S8 D3 facelift

Automatic Climate Control System, On Board Diagnostic (OBD)

Note. Climatronic Control Module J255 and Rear A/C Control Head (Climatronic) E265 are available in different versions. Pay attention to precise assignment on replacement. On Board Diagnostic (OBD) of A/C system is to be performed via the "Guided Fault Finding" function using diagnostic operation system VAS 5051 A. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Front A/C control heads can no longer be cross-exchanged in the familiar way; as soon as a , the Climatronic control module J255 has been adapted in a vehicle, the component protection takes effect. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Component protection can only be canceled by entering specific vehicle data Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. If an A/C control head with active component protection (anti-theft system) is installed in a different vehicle, only the functions necessary for vehicle safety can be selected, comfort functions can no longer be selected. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. If a , Climatronic Control Module J255 or Rear A/C Control Head (Climatronic) E265 is to be replaced, check coding of Climatronic Control Module J255 and adaptation of front Climatronic Control Module J255 and Rear A/C Control Head (Climatronic) E265 before removal via the "Replace control module" function of Guided Fault Finding for this control head. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

DTC recognition

Faults occurring in monitored sensors or components are stored in fault memory together with an indication of the type of fault.

The first step in the fault-finding process is always to start self-diagnosis and interrogate the faults stored. This can be implemented by way of the following

1. Vehicle Diagnosis, Testing and Information System VAS 5051 A
2. Vehicle Diagnosis Service System VAS 5052

The fault information displayed is used in conjunction with a fault table (containing information on possible causes of trouble) to perform pin-pointed repair measures.

Information on handling malfunctions

Note. If a fault condition exists for longer than a pre-determined period, the fault is stored as being static. If the fault condition is then no longer detected for a pre-determined period, the fault is re-classified as being a sporadic fault. This process is constantly repeated. Sporadically occurring malfunctions are identified via indication of "/SP" on the display. A sporadic fault is erased automatically if it no longer occurs for a pre-determined period.

At this time, On Board Diagnostic (OBD) can only be performed using the Diagnostic Operation System VAS 5051 A and Vehicle Diagnosis Service System VAS 5052.

The On Board Diagnostic (OBD) is not just limited to saving, checking and erasing or output diagnostic test mode, but also offers with basic setting, control module identification, adaptation and coding additional options. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions

Note. Vehicle supply voltage OK Fuses OK --> Electrical Wiring Diagrams, Troubleshooting and Component Locations

Note. The various functions of the Diagnostic Operation System VAS 5051 A are described in the pertaining owners manual. Design and function of the Diagnostic Operation System VAS 5051 A are described in Self Study Program.

Scheme 3

1. With the ignition switched off, connect the Diagnostic Operation System VAS 5051 A with diagnostic cable VAS 5051/5 to the 16-pin Data Link Connector (DLC) in the vehicle.
2. Switch ignition on.

Or

1. Start engine.

Note. Observe notes for output Diagnostic Test Mode (DTM) --> Output Diagnostic Test Mode (DTM) .

1. Set operating mode "Auto" on , Climatronic Control Module J255.

Scheme 4

1. Select the function "Vehicle Self-Diagnosis" on diagnostic operation system VAS 5051 A.

Scheme 5

Select the desired vehicle system

1. The , Climatronic Control Module J255 , "08 - A/C/Heating Electronics"
2. Rear A/C Control Head (Climatronic) E265 , "28 - Rear A/C control head" (optional equipment).

Note. Display field - 1 - shows request to select vehicle system Use scroll bar - 2 - on screen to "scroll" display of vehicle systems (for all vehicle models and equipment) that apply to the self diagnostic and also systems that cannot be currently displayed. Wait until "Select diagnostic function" appears in display field - 1 - on diagnostic operation system VAS 5051 A screen.

Note. Identification of control modules now appears in display group - 2 - of diagnostic operation system VAS 5051 A. If the display "vehicle system not installed" appears in display field - 1 - on screen of diagnostic operation system VAS 5051 A , check: Voltage supply to Climatronic Control Module J255 according to wiring diagram. --> Electrical Wiring Diagrams, Troubleshooting and Component Locations Voltage supply to Rear A/C Control Head (Climatronic) E265 according to wiring diagram. --> Electrical Wiring Diagrams, Troubleshooting and Component Locations Wire connection from 16-pin data link connector to Data Bus On Board Diagnostic Interface J533 to , Climatronic control module J255. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. If an additional display field - 2 - "Diagnostic Bus interrupted" appears and with notes for a possible malfunction cause on the diagnostic operation system VAS 5051 A display, check: The voltage supply to the 16-pin Data Link Connector (DLC) according to wiring diagram --> Electrical Wiring Diagrams, Troubleshooting and Component Locations Voltage and condition of Battery A --> 27 - BATTERY, STARTER, GENERATOR, CRUISE CONTROL The display "Diagnostic Bus interrupted" with notes of a possible malfunction cause on screen of Diagnostic Operation System VAS 5051 A appears also when an interference occurred during On Board Diagnostic (OBD), or data exchange between Diagnostic Operation System VAS 5051 A and , Climatronic Control Module J255/Rear A/C Control Head (Climatronic) E265 has been interrupted. The current screen display can be printed out by pressing the "print" function on diagnostic operation system VAS 5051 A screen. Possible malfunction causes can be displayed by pressing the "help" function on diagnostic operation system VAS 5051 A screen. By clicking on the arrow buttons on the diagnostic operation system VAS 5051 A display, you can advance or return in the program or change functions.

1. Now, the desired function can be started via the display of the Diagnostic Operation System VAS 5051 A --> table "selectable functions"

Scheme 6

Note. When OBD is started, the control modules which are activated by the , Climatronic control module J255/Rear A/C Control Head (Climatronic) E265 are indicated, e.g. Drivers Seat Ventilation Control Module J672 , Heated Windshield Control Module J505 , etc. (depending on vehicle equipment).

Checking DTC memory

Note. This article only outlines the function "Check DTC memory". Check DTC memory via "Guided Fault Finding" function, here is also found corresponding notes for determining malfunction location and malfunction repair. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. In addition to DTC display, certain general and ambient conditions under which the malfunction occurred are stored in the control module (e.g. odometer reading, time, date, engine temperature, battery voltage, engine RPM etc.). These items of information are particularly useful for establishing sporadic faults. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. DTC table for malfunction locations and DTC types designated for the A/C system can be found in Guided Fault Finding Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

1. With the ignition switched off, connect the Diagnostic Operation System VAS 5051 A with diagnostic cable VAS 5051/5A to 16-pin Data Link Connector (DLC) in the vehicle and select address word "08" or "28" A/C/Heating Electronics, or "rear A/C control head" --> «Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions»(ref-289225-S22299735562008062700000) .

Indication on display of diagnostic operation system VAS 5051 A

1. Select "02 - Check DTC memory" function.

Scheme 7

Indication on display of diagnostic operation system VAS 5051 A

1. Display field - 1 - indicates the number of stored malfunctions.
2. Display field - 2 - indicates the DTC, the malfunction location and malfunction type of the saved DTC.

Note. By clicking the <-- button, you will return to the selection menu. By pressing the --> button, general and ambient conditions under which the malfunction(s) occurred can be displayed. If no malfunction is recognized but the climate control system does not operate properly (e.g. always or intermittently no cooling performance, control of system insufficient, fresh air blower speed cannot be regulated), proceed as follows: 1. Read measured value block (function 08). 2. Perform final control diagnosis (function 03). 3. Check coding of Climatronic Control Module J255 (function 07). 4. Check adaptation of Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) (function 10). 5. Check cooling/heating performance of A/C system --> A/C cooling output, checking . If fault(s) are found: 1. Eliminate fault. 2. Interrogate fault memory (function 02). 3. Erase fault memory (function 05). 4. Check coding of Climatronic Control Module J255 (function 07). 5. Perform basic setting (function 04). 6. Check adaptation of Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) (function 10). 7. Interrogate fault memory (function 02), eliminate faults displayed if necessary, erase fault memory (function 05) and repeat procedure. 8. End output (function 06). Certain malfunctions can be erased only after starting engine (e.g. "ignition off time period signal" after replacing Instrument Cluster Control Module J285). If a malfunction cannot be erased, start engine and let it run for 1 minute before checking and erasing DTC memory again.

Indication on display of diagnostic operation system VAS 5051 A

1. End output (function 06) --> «End Output»(ref-289225-S39064161082008062700000) .
2. Switch off ignition and unplug diagnostic connector.

Output Diagnostic Test Mode (DTM)

Note. This article only outlines the function "output Diagnostic Test Mode (DTM)". Perform the function "output Diagnostic Test Mode (DTM)" in Guided Fault Finding, here is also found corresponding notes on the function of various components during output DTM. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Note the following as regards final control diagnosis: The request to activate the coolant fan (0 to 100%) is sent by the Climatronic Control Module J255 to the respective Engine Control Module (ECM). Fan is however only switched on by engine control unit when engine is running. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Final control diagnosis can only be implemented at vehicle speeds below 5 km/h. Component locations of activated components --> Components for control and regulation of air conditioner not located in passenger compartment and --> Components for control and regulation of air conditioner located in passenger compartment . Final control diagnosis can be repeated several times if necessary. Control element malfunctions are stored in fault memory. During output Diagnostic Test Mode (DTM), A/C system controls and display of the Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) are switched off. Only during the "Segment test" function are the display segments of the , Climatronic Control Module J255 (Rear A/C Control Head (Climatronic) E265) are actuated. The A/C system control motors are driven into a pre-determined position by the , Climatronic Control Module J255 , (Rear A/C Control Head (Climatronic) E265) after selecting the "output Diagnostic Test Mode (DTM)" function. During final control diagnosis, it is therefore not necessary to wait for control motors to reach a specified position.

Output Diagnostic Test Mode (DTM), initiating

1. With ignition switched off, connect diagnostic operation system VAS 5051 A with diagnostic cable VAS 5051/5A to 16-pin Data Link Connector (DLC) in vehicle --> «Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions»(ref-289225-S22299735562008062700000) .
2. Switch ignition on or start engine.

Note. Switch ignition on (when checking activation of A/C Compressor Regulator Valve N280 , the engine should not be running) Start engine (to check activation of coolant fans)

1. Set the operating mode "Auto" at , Climatronic Control Module J255 (and at Rear A/C Control Head (Climatronic) E265).
2. Select AC/Heating electronics or " Rear A/C control head" using address word "08" or "28" --> «Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions»(ref-289225-S22299735562008062700000) .
3. Open footwell vents (instrument panel, center console and "B" -pillars).
4. Check DTC memory --> «Checking DTC memory»(ref-289225-S22508441102008062700000) .

Indication on display of diagnostic operation system VAS 5051 A

1. Select function "03 - Output Diagnostic Test Mode (DTM)".

Scheme 8

Indication on display of diagnostic operation system VAS 5051 A

1. Display field - 1 - shows which actuator is currently being activated (e.g. 1st actuator in test).
2. Display field - 2 - lists in succession the actuators that were already activated or which one is currently activated. The one currently being actuated appears in the bottom line.

1. By touching the --> button you can call up the next component to be tested. Function and sequence of activated actuators. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Note. By clicking the <-- button, you will return to the selection menu. Final control diagnosis can be terminated by pressing C key. When output DTM is completed, check DTC memory --> Checking DTC memory . Check DTC memory --> Checking DTC memory and read measuring value block --> Read Measuring Value Block when DTM is canceled (e.g. display group number 002 for , Climatronic control module J255).

Erasing DTC memory, End Output

1. With ignition switched off, connect Diagnostic Operation System VAS 5051 A with diagnostic cable VAS 5051/5A --> «Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions»(ref-289225-S22299735562008062700000) .

Erasing DTC memory

Requirements

1. DTC memory of , Climatronic Control Module J255 , and Rear A/C Control Head (Climatronic) E265 was checked --> «Checking DTC memory»(ref-289225-S22508441102008062700000) and all DTCs displayed were repaired.

Indication on display of diagnostic operation system VAS 5051 A

1. With address word "08" , select A/C/Heating Electronics (Climatronic Control Module J255) --> «Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions»(ref-289225-S22299735562008062700000) .
2. Select function "05 - Erase DTC memory".

Scheme 9

Indication on display of diagnostic operation system VAS 5051 A

1. No display appears in display field - 1 -.
2. A field with the note to press the "OK" button appears in display field - 2 -. Data (DTC memory) is erased and the question whether the function should be performed.

Note. "DTC memory was not yet checked" appears in display field - 1 -. Interrogate fault memory. Eliminate any faults. If e.g. ignition was switched off between checking DTC memory and erasing DTC memory, DTC memory will not be erased.

1. Press "OK" button in display field - 2 - on display of diagnostic operation system VAS 5051 A.

As soon as DTC memory is erased, "DTC memory erased" appears in display field - 1 -.

1. Press <-- button on display of diagnostic operation system VAS 5051 A.
2. End On Board Diagnostic (OBD) at Climatronic Control Module J255 --> «End Output»(ref-289225-S39064161082008062700000) .
3. Select Rear A/C Control Head (Climatronic) E265 (optional equipment) via address word "28" --> «Vehicle Diagnostic, Testing and Information System VAS 5051 A , connecting and selecting functions»(ref-289225-S22299735562008062700000) .
4. Erase DTC memory of Rear A/C Control Head (Climatronic) E265 in the same way as for the front Climatronic Control Module J255.

1. End On Board Diagnosis of Rear A/C Control Head (Climatronic) E265.

Wiring and component tests using Test Box V.A.G 1598 A

Special tools, testers and other items required

1. Test box V.A.G 1598/19 (for Climatronic Control Module J255)
2. Test box V.A.G 1598/45 (for Rear A/C Control Head (Climatronic) E265)
3. Diagnostic operation system VAS 5051 A with multimeter leads VAS 5051/7 , DSO measuring leads 1 2 VAS 5051/8 and inductive pickup (50 amp) VAS 5051/9
4. Voltage tester V.A.G 1527 B

1. Connector test set V.A.G 1594/C
2. Temperature measuring instrument
3. Wiring diagram for vehicle system to be tested --> Electrical Wiring Diagrams, Troubleshooting and Component Locations

Note. Electrical check is to be performed as described in guided fault-finding. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Testing of Heated Rear Window Z1

Note. If there is a condition at which heated rear window cannot be switched on (short circuit in connection to rear window, open circuit in voltage supply to front Climatronic Control Module J255), this is stored as a malfunction in Climatronic Control Module J255. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. If voltage measured at Energy Management Control Module J644 at terminal "30" falls below a value stored in Energy Management Control Module J644 , performance level of heated rear window is switched off completely at present (or reduced) to relieve load on generator (duty cycle of activation of 100% reduced to 90 to 0 % by electronics of Climatronic Control Module J255). Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. If heated rear window must be switched off due to insufficient voltage, indicator lamp in heated rear window button on Climatronic Control Module J255 remains switched on, however if switch-off is to last longer than approx. 150 seconds, Climatronic Control Module J255 switches off the indicator lamp. Measuring value block of A/C control head Climatronic Control Module J255 indicates that rear window heater is switched on, or why no activation is occurring despite a request (display group "023" , "033" , "034" and "035") Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Checking actuation of heated rear window operation is described in guided fault-finding for air conditioner. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. The heated rear window stays switched on with outside temperatures up to 0°C until ignition is switched off (heated rear window can be switched manually at anytime). If temperature becomes greater than 0°C during a driving period, switch-off of Heated Rear Window occurs after operating time stored in A/C control head Climatronic Control Module J255 has elapsed (approx. 10 minutes). Heated rear window is switched off automatically by front Climatronic Control Module J255 at outside temperatures greater than 0°C after operating time (approx. 10 minutes) stored in Climatronic Control Module J255 has elapsed (e.g. on vehicles with standard glass, time of activation depends on coding of front Climatronic Control Module J255 --> Read Measuring Value Block Read measured value block, display group "050").

Test prerequisites

Note. Vehicle standing in a clean atmosphere (away from running engines, exhaust vents, etc.) Engine compartment and plenum chamber clean (not contaminated with oil or fuel) Engine compartment and plenum chamber not sprayed with cleaning agents or preservatives containing solvents

Test requirements

1. Ambient temperature greater than 15°C
2. Clean radiator and condenser (clean if necessary)
3. Compressor drive ribbed belt is OK and correctly tensioned and belt pulley actually drives the compressor (on vehicles with 8-cyl. MPI engine or 12-cyl. engine).
4. Compressor drive unit is mounted correctly, compressor is actually driven (on vehicles with 8-cyl. FSI engine or 10-cyl. engine) --> «Compressor drive unit, checking, replacing»(ref-289225-S40868384782008062700000) .

1. All air ducts, covers and seals OK and properly fitted
2. Air flow through dust and pollen filter not obstructed by dirt.
3. Vehicle not exposed to sunlight
4. Engine is warm

1. DTC memory of front Climatronic Control Module J255 (and of Rear A/C Control Head (Climatronic) E265) was checked and erased, basic setting was performed and coding of front Climatronic Control Module J255 was checked --> «Climatronic Control Module J255 , coding»(ref-289225-S04494600862008062700000) and. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
2. Adaptation of Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) was checked --> «Climatronic Control Module J255 and Rear A/C Control Head (Climatronic) E265 , adaptation»(ref-289225-S21352035252008062700000) . Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
3. All instrument panel vents open
4. Hood closed

1. Settings on Climatronic Control Module J255 or on MMI (Multi Media Interface)

1. Operating mode "Auto".
2. Temperature selection "LO" for drivers and passengers side.
3. Compressor on (function "Econ" not active in MMI).

1. Functions with engine running

1. Coolant Fans V7 is running (speed depends on pressure in refrigerant circuit and engine temperature).
2. Fresh Air Blower V2 runs at maximum speed.
3. Air conditioner switches to recirculating-air mode (approx. 1 minute after starting the vehicle, the fresh/back pressure flaps will be closed and recirculating-air flap will open, Fresh Air Blower V2 extracts air from passenger compartment beneath instrument panel).
4. No operation of Coolant Pump V50.

1. Left Heat Regulating Valve N175 and Right Heat Regulating Valve N176 are closed (coolant hoses or coolant lines to heater cores of heating system cool down).

Note. If one of these test requirements is not met, check DTC memory of Climatronic Control Module J255 , perform output Diagnostic Test Mode (DTM) and read measuring value block (display groups "001" and "002"). Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

1. Coolant circuit has been bled according to specifications: --> «19 - ENGINE - COOLING SYSTEM»(ref-289203-S15357943982008062700000) for 4.2 LITER V8 4V ENGINE MECHANICAL, ENGINE CODE(S): BVJ 19 - ENGINE - COOLING SYSTEM for 4.2 LITER V8 5V ENGINE MECHANICAL, ENGINE CODE(S): BFM «19 - ENGINE - COOLING SYSTEM»(ref-289204-S03664241582008062700000) for 5.2 LITER 10-CYL. 4V ENGINE MECHANICAL, ENGINE CODE(S): BSM «19 - COOLING SYSTEM»(ref-289206-S27114819052008062700000) for 6.0 LITER 12-CYL. 4V ENGINE MECHANICAL, ENGINE CODE(S): BSB
2. All air ducts, covers and seals OK and properly fitted
3. Air flow through dust and pollen filter not obstructed by dirt.
4. Engine warm

1. Vehicle battery - A - OK and adequately charged (to prevent Energy Management Control Module J644 from switching off Climatronic Control Module J255 during test).
2. DTC memory of Climatronic Control Module J255 (and of Rear A/C Control Head (Climatronic) E265) was checked and erased, basic setting was performed and coding of Climatronic Control Module J255 was checked --> «Climatronic Control Module J255 , coding»(ref-289225-S04494600862008062700000) and. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
3. Adaptation of Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) was checked --> «Climatronic Control Module J255 and Rear A/C Control Head (Climatronic) E265 , adaptation»(ref-289225-S21352035252008062700000) . Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
4. Vehicle not exposed to sunlight