Wiring and Component Check Using Test Box V.A.G 1598 A
Wiring And Component Check Using Test Box V.A.G 1598A
Special tools and equipment
- Test Box V.A.G 1598A as well as corresponding Adapter V.A.G 1598/11 and Adapter - 16 Terminals V.A.G 1598/12
- Diagnostic Operation System VAS 5051A with Multimeter Leads VAS 5051/7, Dso Measuring Leads 12 VAS 5051/8 and Inductive Pickup (50 Amp) VAS 5051/9
- Voltage tester V.A.G 1527 B
- Connector Test Set V.A.G 1594C
- Temperature measuring instrument (commercially available)
NOTE: During vehicle On Board Diagnostic (OBD), there must not be any Test Box V.A.G 1598A adapters connected to the operating and display module, Climatronic Control Module J255.
Connect Test Box V.A.G 1598A to wiring harness connectors of Climatronic Control Module J255
- Switch off ignition.
- Remove operating and display module, Climatronic Control Module J255.
- Connect Adapter V.A.G 1598/11 and Adapter- 16 Terminals V.A.G 1598/12 to disconnected connectors of operating and display module, Climatronic Control Module J255.
NOTE:
- Do not connect operating and display module, Climatronic Control Module J255.
- For measurement, connect the Test Box V.A.G 1598A to the relevant adapter.
- The assignment of the sockets on the Adapter - 16 Terminals V.A.G 1598/12 is identical to the pin assignment of the operating and display module, Climatronic Control Module J255.
- The assignment of the sockets on the Adapter V.A.G 1598/11 is not identical to the pin assignment of the operating and display module, Climatronic Control Module J255.
Socket assignment for Test Box V.A.G 1598A with Adapter V.A.G 1598/11
NOTE:
- The terminal assignment of the connectors "A" and "B" for the Adapter V.A.G 1598/11 is not identical to the assignment of the sockets at the Test Box V.A.G 1598A.
- The terminal assignment of the connector "C" for the Adapter V.A. G 1598/11 is identical to the assignment of the sockets at the Test Box V.A.G 1598A.
- The terminal assignment of the connector "D" for the Adapter -16 Terminals V.A. G 1598/12 is identical to the assignment of the sockets at the Test Box V.A.G 1598A.
- As the connectors to the operating and display module, Climatronic Control Module J255 are distributed over two adapters (Adapter V.A.G 1598/11 and Adapter-16 Terminals V.A.G 1598/12), there is no Ground (GND) connection for test purposes with the Adapter V.A.G 1598/11 connected. When performing electrical checks, it is therefore necessary for various test steps to take measurements with respect to a suitable Ground (GND) point on the vehicle body or to use a second Test Box V.A.G 1598A (with the Adapter-16 Terminals V.A.G 1598/12 connected, Ground (GND) is applied to socket "13").
Checking
NOTE:
- All fuses OK
- Adapter V.A.G 1598/11 and Adapter-16 Terminals V.A.G 1598/12 connected to disconnected connectors of operating and display module, Climatronic Control Module J255
- On Diagnostic Operation System VAS 5051A , set "Measurement" mode.
- Select the measurement mode required in the various test steps on the Diagnostic Operation System VAS 5051A by touching the appropriate key on the display of the Diagnostic Operation System VAS 5051A.
Electrical tests (to be performed on Climatronic Control Module J255), overview
NOTE: Various items of information are transmitted via the CAN-Bus comfort system (reading measuring value block). There are no electrical checks provided for this information. Measuring Value Blocks (Function 08)
Test Steps "1" To "4"
Test step "1"
Voltage supply and Ground (GND) connection of operating and display module, Climatronic Control Module J255
Test step "2'
Temperature sensors/sensors
Temperature-depending resistance values sensors/sensors
Test step "3"
Voltage supply and wiring to Fresh Air Blower Control Module J126 and Fresh Air Blower V2
- Test step 3.1 Checking power supply to Fresh Air Blower V2
- Switch off ignition.
- Remove glove compartment.
- Disconnect connector - A - from Fresh Air Blower Control Module J126 - B -.
- Measure voltage between contact - 4 - and contact - 3 - at connector - A -.
Specified value: approx. Battery voltage
NOTE:
- If the voltage is below Battery voltage, use wiring diagram to repair voltage supply/Ground (GND) connection.
- On vehicles equipped with "sunroof with solar cells", there is voltage generated by the sunroof solar cells at terminal -6-of connector -A- when sunroof is closed.
- The Fresh Air Blower Control Module J126 is constantly monitored by the operating and display module, Climatronic Control Module J255. Any malfunctions occurring are stored in the DTC memory. The current status of the Fresh Air Blower V2 is displayed in the measuring value block (display group "018"). Measuring Value Blocks (Function 08)
Wiring connection to Fresh Air Blower Control Module J126
Test step "4"
Air conditioner positioning motors with potentiometers
NOTE:
- The resistance of the potentiometers in the control motors (specification: 3.6 to 5.7 kOhms between contacts "1" and "3") can only be measured directly at the control motor (parallel connection).
- The resistance of the potentiometers in the control motors (between contacts "1" and "2 " as well as "3" and "2") is governed by the position of the control motor and is only to be measured with the control motor installed. The upper specification is not attained in test steps "4.1" and "4.2". (To achieve the upper specification, all connectors would have to be disconnected from the other control motors during measurement because of the parallel connection).
- If the operating and display module, Climatronic Control Module J255 detects the fault "Potentiometer short to Ground (GND)" or "Open circuit/short to positive", check all potentiometers in the control motors as well as the corresponding wiring.
- If several control motors are simultaneously displayed as being defective in the DTC memory and if no malfunction is found in test step "4", check the potentiometers in all control motors and the wiring between the individual control motors for short circuit (e.g. between Defroster Flap Motor V107 and Central Air Flap Motor V70 ; with connectors disconnected from all control motors as well as from operating and display module, Climatronic Control Module J255, the measuring instrument reading between sockets "1", "2" and "3" in the corresponding connector must be "infinity ohms").
Test Steps "5" To "9"
Test step "5"
Pressure signal from High Pressure Sensor G65
Checking pressure signal from High Pressure Sensor G65
This display appears on the oscilloscope screen if the following conditions are fulfilled.
- Ignition switched on (positive and Ground (GND) applied to High Pressure Sensor G65 )
- Oscilloscope settings: 5 V/div. DC (5 V per unit DC voltage) 5 ms/div. 5 milliseconds per unit)
- Measuring lead (signal wire) connected to socket "7" of Test Box V.A.G 1598A (with Adapter-16 Terminals V.A.G 1598/12)
- Measuring wire (screen) connected to socket "14" (Ground (GND)) of Test Box V.A.G 1598A (with Adapter -16 Terminals V.A.G 1598/12 )
NOTE:
- The illustration shows the signal transmitted at a refrigerant circuit pressure of approx. 7 bar absolute, corresponding to a duty cycle of approx. 25% (level occurring with compressor not running, ambient temperature of 30 degrees C and refrigerant circuit charged).
- The pulse width - A - is governed by the pressure in the refrigerant circuit (area - A -becomes broader as pressure increases).
- The signal distance - B -is always 20 milliseconds (corresponding to a frequency of 50 Hertz).
- The duty cycle is derived from the ratio of pulse width - A - to signal distance - B-.
Connector assignment at High Pressure Sensor G65
Contact -1 - Ground (GND)
Contact - 2 - Signal output (square-wave signal to operating and display module, Climatronic Control Module J255 )
Contact - 3 - B- (terminal "75")
NOTE:
- The compressor does not switch on if the connector - B -is disconnected.
- The High Pressure Sensor - A - is an electronic control unit which generates a square-wave signal with a ratio which varies with the pressure in the refrigerant circuit.
Pressure signal from High Pressure Sensor G65
- A - Pressure on high-pressure end of refrigerant circuit in bar (absolute)
- B - Ratio of square-wave signal
- C - Characteristic curve
NOTE:
- The operating and display module, Climatronic Control Module J255 switches on the compressor (by way of activation of the A/C Compressor Regulator Valve N280) in the case of a ratio of greater than 12 % (corresponding to approx. 1.8 bar absolute pressure) and less than 87.5% (corresponding to approx. 32 bar absolute pressure) if there is no compressor shutoff condition.
- If the signal ratio is less than 12% or greater than 87.5%, the compressor does not switch on (the A/C Compressor Regulator Valve N280 is not activated).
- The signal ratio and the pressure calculated by the operating and display module, Climatronic Control Module J255 are displayed in the measuring value block(display group "001" ). Measuring Value Blocks (Function 08)
- At absolute pressure, 0 bar corresponds to an absolute vacuum. Normal ambient pressure thus corresponds to roughly 1 bar absolute. On the scales of most pressure gauges, 0 bar corresponds to an absolute pressure of one bar (can be seen from -1 mark below 0).
- The operating and display module, Climatronic Control Module J255 transmits the request for activation of the Coolant Fan V7 via the CAN-Bus comfort system to the engine control module, which then causes the Coolant Fan Control (FC) Control Module J293 to switch on the Coolant Fan V7 :
- -As soon as the compressor is switched on irrespective of the pressure in the refrigerant circuit.
- The operating and display module, Climatronic Control Module J255 transmits the request for increased Coolant Fan V7 speed via the CAN-Bus comfort system to the engine control module:
- 100% is currently only requested at a pressure of approx. 26 bar in the refrigerant circuit.
- The signal generated by the High Pressure Sensor G65 is also used for engine control. The operating and display module, Climatronic Control Module J255 transmits the information via the CAN-Bus comfort system to the engine control module (torque required for driving compressor is governed by pressure in refrigerant circuit). Depending on the version of the engine control module, the signal is displayed as a ratio in the measuring value block "Guided Fault-Finding" Vehicle Diagnosis, Testing Info. System VAS5051B or Vehicle Diagnosis Service Syst. VAS5052
Test step "6"
Activation for A/C Compressor Regulator Valve N280
Engagement signal for A/C Compressor Regulator Valve N280 , checking
- Switch off ignition.
- Connect operating and display module, Climatronic Control Module J255 to vehicle wiring harness.
- Disconnect connector at air conditioner compressor (to A/C Compressor Regulator Valve N280).
- Use adapter from Connector Test Set V.A.G 1594C to reestablish connection between connector - A - and connector - B - at compressor (to A/C Compressor Regulator Valve N280).
NOTE: Use can also be made for this test of an improvised adapter. This requires, for example, one connector -A- and - B - each (with part number 1JO 973 702 and 1JO 973 802 and the corresponding plug contacts), two commercially available sockets for banana plugs - C - and two wires with a cross section of 0.5 sq mm .
- Connect Dso Measuring Leads 1 2 VAS 5051/8 to adapter leads.
- Measuring lead (signal wire) to contact 2
- Measuring wire (screen, Ground (GND)) to contact 1
- On Diagnostic Operation System VAS 5051 A , set measurement mode: "DSO" (Digital Storage Oscilloscope).
- Settings 5V/div DC, 0.5 ms/div (5 V DC and 0.5 milliseconds per unit)
- Start engine.
- On operating and display module, Climatronic Control Module J255 , select "Lo" temperature setting for drivers and front passengers side.
- On operating and display module, Climatronic Control Module J255 , press buttons "Auto" and "Econ" to activate and deactivate A/C Compressor Regulator Valve N280.
Display on oscilloscope screen will be as follows depending on setting on operating and display module, Climatronic Control Module J255 :
- In "OFF" or "Econ" mode: no square-wave signal (A/C Compressor Regulator Valve N280 is not activated)
- In "Auto" mode and "Lo" temperature setting: Square-wave signal with pulse width - A -between 75% and 100% (A/C Compressor Regulator Valve N280 is activated)
NOTE:
- The illustration shows a signal with a ratio of approx. 80%.
- The pulse width - A - is governed by the required cooling output, electrical system voltage etc. (over width of area -A-, current is controlled via A/C Compressor Regulator Valve N280 by operating and display module, Climatronic Control Module J255).
- The signal distance - B- is always 2 milliseconds (corresponding to a frequency of 500 Hertz).
- The duty cycle is derived from the ratio of pulse width - A - to signal distance - B -.
- The setting on the operating and display module, Climatronic Control Module J255 and measured ambient influences govern the pulse width of the square-wave signal (signal ratio between 100% and greater than 30%, A/C Compressor Regulator Valve N280 is activated such that the compressor output required to obtain the specified temperatures is achieved).
NOTE:
- In "Auto" mode with "Lo" temperature setting, the A/C Compressor Regulator Valve N280 is activated such that the max. perm. current of approx. 0.6 to 0.8 A flows via the A/C Compressor Regulator Valve N280 (maximum compressor output).
- In control mode, the activation time is governed by the required cooling output and vehicle electrical system voltage, for example. It is however always of sufficient duration to achieve a mean current of 0.3 A.
Test step "7"
Sunlight Photo Sensor G107
NOTE:
- There are different versions of the operating and display module, Climatronic Control Module J255 and the Sunlight Photo Sensor G107. Attention must therefore be paid to the exact assignment when replacing an operating and display module.
- As of VIN 400000 in Model Year 2005 (for Saloon and Avant; gradual introduction for the Cabrio in week 46/04 without prior specification of any particular VIN), vehicles are to be installed with a modified Sunlight Photo Sensor G107 and a modified operating and display module, Climatronic Control Module J255. Operating and display units, Climatronic Control Module J255 with part No. index up to "AH" are only to be installed with the Sunlight Photo Sensor G107 with part No. 8E0 907 539. Operating and display units, Climatronic Control Module J255 with part No. index "AJ" onwards are only to be installed with the Sunlight Photo Sensor G107 with part No. 8P0 907 539.
- In the event of incorrect assignment between the Sunlight Photo Sensor G107 and the operating and display module, Climatronic Control Module J255, the operating and display module, Climatronic Control Module J255 cannot evaluate the signal from the Sunlight Photo Sensor G107 and there will be problems with air conditioner control.
