Contents Section: Automatic HVAC System All sections

Automatic Climate Control: Diagnosis Saab 9-5 I рестайлинг 2

Automatic HVAC System 45 illustrations ~3802 words

Diagnostics

In the event an internal fault in the control module, diagnostic trouble code B1605 is generated

Scheme 362

Scheme 362: Control module power supply

If there is no power supply then background lighting does not come on when the ignition is switched on.

Scheme 363

Scheme 363: Diagnostics

Scheme 364

Scheme 364: Ground

If ground is not present, the display will not light up when the ignition is turned on.

If sensor ground is short-circuited to 5 V or B+ then diagnostic trouble code B2945 is generated.

Scheme 365

Scheme 365: Diagnostics

Scheme 366

Scheme 366: Cabin Temperature Sensor

The cabin temperature sensor is fitted in the roof panel by the rear-view mirror and is the NTC type. The sensor is supplied with 5 V from K1 pin 16 via a 10 kohms resistor built into the ACC unit and is grounded from K1 pin 22. This way the voltage over the sensor is inversely proportional to the temperature (the voltage drops when the temperature rises). The value is used to calculate the current temperature at head height for front seat passenger and driver. In addition, the following are used as input values

  1. outside temperature
  2. time since engine last ran
  3. time since start
  4. blended-air temperatures
  5. fan speed
  6. solar irradiance

The cabin temperature sensor's value is only included in the calculation at the start for the ACC unit's regulation. The calculated temperatures are then compared with those the driver and passenger set with the ACC unit's temperature knob. The set temperature is corrected slightly with respect to the outside temperature so that the perceived temperature should equal the set temperature.

As soon as a difference occurs, the blended-air temperature must be increased or decreased. The control module turns the air-blending flap in question until the required blended-air temperature is achieved.

Scheme 367

Scheme 367

In the event of open circuit or short circuit diagnostic trouble code B1350 is generated.

Outside temperature when ignition is switched on is used as substitute value followed by mean value of the calculated temperatures at head height for front seat passenger and driver.

Scheme 368

Scheme 368: Blended-Air Temperature Sensor, LH

The mixed air temperature sensor is the NTC type and has a sensor body inserted in the left-hand floor outlet. The sensor is supplied with 5 V from K1 pin 19 via a 6.8 kohms resistor built into the ACC unit and is grounded from K1 pin 24. This way the voltage over the sensor is inversely proportional to the temperature (the voltage drops when the temperature rises).

The value is used so that the control module can turn the air-blending flap until the required blended-air temperature is obtained.

In the event of open circuit or short circuit diagnostic trouble code B1345 is generated.

The relative opening of the air-blending flap in question, multiplied by the coolant temperature, is used as substitute value.

Scheme 369

Scheme 369: Diagnostics

Scheme 370

Scheme 370: Blended-Air Temperature Sensor, RH

The mixed air temperature sensor is the NTC type and has a sensor body inserted in the right-hand floor outlet. The sensor is supplied with 5 V from K1 pin 18 via a 6.8 kohms resistor built into the ACC unit and is grounded from K1 pin 25. This way the voltage over the sensor is inversely proportional to the temperature (the voltage drops when the temperature rises).

The value is used so that the control module can turn the air-blending flap until the required blended-air temperature is obtained.

In the event of open circuit or short circuit diagnostic trouble code B2345 is generated.

The relative opening of the air-blending flap in question, multiplied by the coolant temperature, is used as substitute value.

Scheme 371

Scheme 371: Diagnostics

Scheme 372

Scheme 372: Solar Sensor

The solar sensor, located at the top of the dashboard, contains 5 solar cells: LH, RH, front, rear and top. The plastic housing is colored so that only infrared light (heat radiation) can penetrate. The solar sensor is fed B+ pulses from K1 pin 26 and is grounded via K1 pin 22. Voltage from the 5 sensor elements is sent in sequence to K1 pin 17 of the ACC unit.

For the control module to be able to identify which solar cell is reporting, each transmission is begun with the pulse pattern 5 V - 0 V - 5 V. The control module synchronizes the solar sensor pulse transmissions by sending short ground pulses of 25 Hz from K1 pin 26.

The control module uses the voltage from the 5 solar cells to calculate the sun's intensity, bearing and height.

The values are used to calculate the current temperature at head height for the front seat passenger and driver. The following are also used as default values

  1. outside temperature
  2. time since engine last ran
  3. time since start
  4. blended-air temperatures

The calculated temperatures are compared to those the driver and passengers have set on the ACC unit display. The set temperature is adjusted with respect to the outside temperature so that the perceived temperature corresponds with the set temperature.

As soon as a difference occurs, the blended-air temperature must be increased or decreased. The control module turns the air-blending flap in question until the required blended-air temperature is achieved.

In the event of open circuit or short circuit diagnostic trouble code B1340 is generated. The latest valid value is used as substitute value. When the ignition is switched on 0 W/m 2 is used.

Scheme 373

Scheme 373: Diagnostics

Scheme 374

Scheme 374: Parking Heater

In the event of open circuit or short circuit diagnostic trouble code B2490 is generated.

The diagnostic tool shows 100% at max. heat and 0% at max. cold.

Scheme 375

Scheme 375: Diagnostics

Scheme 376

Scheme 376: Stepping Motor, Right-Hand Air-Blending Flap

The stepping motor has two windings. The windings are energized in a special order with short pulses. This makes the motor move in short steps, which is how it got its name. The direction of rotation can be changed. When the motor is stationary, both the windings are energized continuously to lock the motor. The stepping motor does not require a feedback coupling to the control module (position sensor). By sending a known number of pulses, the control module always knows how far the flap has moved. This is possible on condition that the control module has calibrated itself by turning the flap to its respective end positions so that it knows the position of the flap.

Calibration takes place by simultaneously pressing the AUTO and REC buttons. A sound and the message, ACC:CALIBR. STARTED are indicated in the main instrument unit, confirming the calibration. Calibration must take place if the battery is disconnected/discharged, if the ACC unit or stepping motor is replaced, or their positions are changed.

The climate system has three air-blending flaps, one for the driver's zone and one air-blending flap for the front seat passenger that is connected via a link with the air-blending flap for the rear seat passengers.

The stepping motor for the right-hand air-blending flap is supplied with current from the ACC unit's K1 pins 34 and 32 (winding 1), and K1 pins 33 and 31 (winding 2).

The flap is set by the control module using the air-blending temperature sensor for the right-hand side so that the requested air-blending temperature is obtained.

In the OFF position the flap stops in the last selected position.

When the ignition is switched off the air-blending flap will first stop in the latest selected position and after 8 minutes it moves to park position, max. cold (0%).

In the event of open circuit or short circuit diagnostic trouble code B2290 is generated.

The diagnostic tool shows 100% at max. heat and 0% at max. cold.

Scheme 377

Scheme 377: Diagnostics

Scheme 378

Scheme 378: Stepping Motor, Air Distribution Flap

The stepping motor has two windings. The windings are energized in a special order with short pulses. This makes the motor move in short steps, which is how it got its name. The direction of rotation can be changed. When the motor is stationary, both the windings are energized continuously to lock the motor. The stepping motor does not require a feed-back coupling to the control module (position sensor). By sending a known number of pulses, the control module always knows how far the flap has moved. This is possible on condition that the control module has calibrated itself by turning the flap to its respective end positions so that it knows the position of the flap.

Calibration takes place by pressing the AUTO and REC buttons. A sound and the message, ACC:CALIBR. STARTED are indicated in the main instrument unit, confirming the calibration. Calibration must take place if the battery is disconnected/discharged, if the ACC unit or stepping motor is replaced, or their positions are changed.

The climate system has two air distribution flaps, one twin-flap for the driver's zone and the front seat passenger, and one for the rear seat passengers that is linked to the front flap. The two flaps are maneuvered by a stepping motor fitted to the passenger side of the heating and ventilation unit. Consequently, the air distribution is common for the passenger and the driver zones. The air is distributed to the defroster, floor/rear door windows or the dashboard/rear center vents.

The stepping motor for the air distribution flap is supplied with current from the ACC unit's K1 pins 38 and 36 (winding 1) and K1 pins 37 and 35 (winding 2).

The air distribution is controlled depending on the requested mixed air temperature for the driver's zone.

Defrost is selected first after cold starting, see Cold Start in Auto .

Required air distribution can also be selected manually on the panel.

In the OFF position the flap stops in the last selected position.

When the ignition is switched off the air distribution flap will first stop in the latest selected position.

After 8 minutes and when the outside temperature is under 18°C the air distribution flap moves to park position floor (50%). If the outside temperature rises above 18°C the air distribution flap moves to ventilation (0%).

Scheme 379

Scheme 379

In the event of open circuit or short circuit diagnostic trouble code B2400 is generated.

The diagnostics tool shows 100% in defrost position and 0% in panel position.

Scheme 380

Scheme 380: Ventilation Fan

The fan is supplied with +30 from fuse 22. The control module regulates the fan control unit, which supplies the fan motor on the ground side. The fan control unit is mounted on the fresh air filter cover.

The fan control unit is supplied with B+ from K1 pin 20 on the ACC unit and power grounded from grounding point G41P. The ground lead is also reference ground from K1 pin 1 on the ACC unit. The fan control unit is controlled by an analogue voltage of 0-5 V from K1 pin 13 on the ACC unit. The fan current increases as the control voltage increases.

The control module regulates the fan current in the following way

  1. If the engine is stationary, 0 A is selected.
  2. When the starter motor engages, 0 A is selected.
  3. When starting in cold weather, the coolant temperature and outside temperature are determined. The lower the values, the lower the current. For conditions for cold starts, see «COLD START IN AUTO»(ref-278647-S14401058132008013000000) .
  4. Under normal driving conditions it is at its lowest when the current blended-air temperature corresponds with the requested temperature in both zones (none of the zones requires cooling or heating). The current is increased as soon as either of the zones requires cooling or heating.
  5. At higher speeds the air from outside will be forced into the car. The faster the car travels the greater the effect of the incoming air. The ACC unit calculates an air flow value based on the speed of the car, air and blending flap position.

Scheme 381

Scheme 381

With manual selection of defrost or HI, 6 fan steps are shown. With selection of LO, 8 fan steps are shown which is MAX fan speed. Required fan speed can also be selected manually on the panel. If fan speed 0 is selected then the A/C will be disengaged, but otherwise the ACC system is fully active.

Fan speed is shown with a number of positions by the ACC unit knob.

In the event of short circuit in the control circuit diagnostic trouble code B2425 is generated.

Scheme 382

Scheme 382: DC motor, Air Recirculation Flap

The climate system has two air recirculation flaps that are linked together. The two flaps are controlled by a DC motor fitted on the passenger side of the heating and ventilation unit. Using these flaps the fan can retrieve air from outside or inside the cabin, there are no intermediate positions. When the position is changed the control module releases voltage for approx. 10 seconds. The motor is supplied with current from the ACC unit's K1 pins 27 and 28. The output poles are inverted to change the rotation direction of the motor.

If the ignition has been off for more than 10 minutes then air recirculation is selected at the earliest 0-15 seconds after starting the engine and only if the outside temperature is above 25°C and the requested blended-air temperature is the lowest possible for both zones (both zones must be cooled down considerably after start).

Following which, air recirculation can be selected automatically as necessary by the control module in the event of high thermal load, such as low car speed, high outside temperature, high solar intensity or with high coolant temperature.

Air recirculation can also be selected manually on the panel. An LED in the button indicates when the air is being recirculated.

When the ignition is off fresh air is selected after 10 seconds.

Scheme 383

Scheme 383

In the event of open circuit or short circuit diagnostic trouble code B2410 is generated.

Scheme 384

Scheme 384: Solenoid Valve, Shut-Off Valve, Heat Exchanger

The climate system is equipped with a vacuum controlled shut-off valve for the heat exchanger. The aim is to prevent coolant circulating in the heat exchanger when necessary so that maximum cooling efficiency can be achieved. The control module controls a solenoid valve that in turn controls the shutoff valve.

The solenoid valve is supplied from +54 via fuse 31 and is controlled on the ground side from the ACC unit's K1 pin 14.

When the control module grounds the output the solenoid valve opens and releases a vacuum to the shut-off valve which in turn shuts off coolant supply.

The control module closes the shut-off valve if the required blended-air temperature is below approximately 6°C for both zones (both zones must be cooled down considerably).

In the event of open circuit or short circuit diagnostic trouble code B2375 is generated.

Scheme 385

Scheme 385: Diagnostics

Scheme 386

Scheme 386: Circulation Pump

Cars with parking heater are equipped with a circulation pump for the parking heater. The aim is to achieve and even flow through the heat exchanger when the parking heater is active.

The circulation pump is supplied from +30 via fuse 8 and is controlled on the ground side from the control module's K1 pin 15.

The control module starts the pump when the engine is on or when the parking heater is active.

Scheme 387

Scheme 387: Programming

The function can be programmed using the diagnostic tool if the circulation pump is retrofitted.

In the event of open circuit or short circuit diagnostic trouble code B2380 is generated.

Scheme 388

Scheme 388: Panel Functions

All functions are controlled automatically with the selected temperature. The AUTO button LED comes on and confirms that the AUTO function is active.

AC OFF, electrically heated rear window, air recirculation, seat fans, heating pads and temperature up or down can be selected without leaving AUTO.

Scheme 389

Scheme 389: Temperature up or down

Selection of inside temperature for driver and passenger zone in steps of 1°C between 16°C and 27°C, alternatively between 60°F and 80°F. An LED on the temperature knob shows selected temperature.

When the ignition is switched on the following values are used

Recommended setting is 21+/-3°C, alternatively 69+/-5°F.

With a value higher than 26°C, alternatively 80°F, HI is indicated with a red LED and the system is set in accordance with the following

  1. fan speed 6 steps
  2. air distribution in defrost/floor position
  3. air mixture in full heat position for side in question. 100% is shown on the diagnostic tool.
  4. air recirculation in off position

With a value lower than 16°C, alternatively 60°F, LO is indicated with a blue LED (the passenger cannot select LO if the driver has not) and the system is set in accordance with the following

  1. fan speed MAX, 8 steps
  2. A/C ON/OFF
  3. air distribution in panel position
  4. air mixture in full cold position for side in question, 0% is shown on the diagnostic tool
  5. air recirculation in on position, when A/C is active

During calibration any diagnostic trouble codes for the flaps are stored in the ACC unit and can be read using the diagnostic tool.

Scheme 390

Scheme 390: Cold Start in Auto

For a cold start the windscreen must first be de-iced or demisted. Following which, the cabin must be heated as quickly as possible. When the outside air and coolant are cold the fan speed must be adapted so that the air temperature after the heat exchanger is always as high as possible.

If the indication for a heated front seat goes out 5 seconds after a manual selection then this indicates that a fault has arisen in the heating pad. The diagnostic trouble code can be read in the diagnostic tool.

Scheme 391

Scheme 391: Ventilated Front Seat

For the Saab 9-5 the seat ventilation can be obtained as an option for the electrically adjustable front seat. The system consists of one fan in the seat cushion and one in the backrest cushion, that draw in air and moisture through perforated holes in the seat cushion and backrest.

The seat fan is located in the seat well. The backrest fan is located on the curved plate in the backrest frame.

The ventilated front seats have leather upholstery with perforated holes and foam cushions with punched holes. The air and moisture is directed through ducts in the seat cushion and backrest under the seat.

Connector 1 (K1) 40-pin, test readings

Pin no.Component/functionIn/OutTest conditionsBetween X and YTest reading
1Ground for control moduleInIgnition ON4-1B+
2Seat ventilation, leftOut2-11Stage 1: 9.5 V Stage 2: B+
3Parking heater connectionInActivate parking heater3-1B+
4Power supply (+15 circuit)InIgnition ON or active control module4-1B+
5I-Bus (-)In/OutIgnition ON5-12-3 V
6I-Bus (+)In/OutIgnition ON6-12-3 V
7PPS "Passenger Airbag" (US/CA)(from DICE)InIgnition ON7-1PWM signal 3.5-B+
8PPS "ON" (US/CA)Out
9+15InIgnition ONB+
10PPS "OFF"OutUS/CA
11Seat ventilation, return groundIn11-2/12
12Seat ventilation, rightOut12-11Stage 1: 9.5 V Stage 2: B+
13Fan control module's control voltageOutIgnition ON change fan speed13-10-5 V
14Shut-off valve, heat exchangerOutIgnition ON4-14B+
15Circulation PumpOutActivate motor4-15B+
16Cabin temperature sensorInIgnition ON16-22See TECHNICAL DATA
17Solar sensor, test lineInIgnition ON17-220-5V PULSE TRAIN, LP Hi-Lo p
18Blended-air temperature sensor, RHInIgnition ON18-25See TECHNICAL DATA
19Blended-air temperature sensor, LHInIgnition ON19-24See TECHNICAL DATA
20B+ -voltage ON fan control moduleOutIgnition ON20-1B+
21Power supply +30InPower supply +3021-1B+
22Solar sensor groundOutIgnition ON26-2212 V, 25 Hz TRIGGER, 1% LP Hi_Lo p
22Interior temperature sensor groundOutIgnition ON16-22See TECHNICAL DATA
24Mixed air temperature sensor, left groundOutIgnition ON19-24See TECHNICAL DATA
25Mixed air temperature sensor, right groundOutIgnition ON18-25See TECHNICAL DATA
26Solar sensor, B+ power supply (clock pulse)OutIgnition ON26-2212 V, 25 Hz TRIGGER, 1% LP Hi-Lo p
27Power supply, air recirculation motorOutActivate fresh air27-28+12 V for approx. 10s
28Power supply, air recirculation motorOutActivate air recirculation28-2712 V for approx. 10s
29Stepping motor, mixed air, leftOutIgnition ON activate motor29-4050 Hz/50 % LP Hi-Lo
30Stepping motor, mixed air, leftOutIgnition ON activate motor30-3950 Hz/50 % LP Hi-Lo
31Stepping motor, mixed air, rightOutIgnition ON activate motor31-3350 Hz/50 % LP Hi-Lo
32Stepping motor, mixed air, rightOutIgnition ON activate motor32-3450 Hz/50 % LP Hi-Lo
33Stepping motor, mixed air, rightOutIgnition ON activate motor33-3150 Hz/50 % LP Hi-Lo
34Stepping motor, mixed air, rightOutIgnition ON activate motor34-3250 Hz/50 % LP Hi-Lo
35Stepping motor, air distribution flapOutIgnition ON activate motor35-3750 Hz/50 % LP Hi-Lo
36Stepping motor, air distribution flapOutIgnition ON activate motor36-3850 Hz/50 % LP Hi-Lo
37Stepping motor, air distribution flapOutIgnition ON activate motor37-3550 Hz/50 % LP Hi-Lo
38Stepping motor, air distribution flapOutIgnition ON activate motor38-3650 Hz/50 % LP Hi-Lo
39Stepping motor, mixed air, leftOutIgnition ON activate motor39-3050 Hz/50 % LP Hi-Lo
40Stepping motor, mixed air, leftOutIgnition ON Activate motor40-2950 Hz/50 % LP Hi-Lo

PINOUTS REFERENCE CHART

Connector 2 (K2) 6-pin, test readings

Pin no.Component/functionIn/OutTest conditionsBetween X and YTest reading
1Seat heating, leftOutIgnition ON Activate motor1 (K1) - 1B+
2-3+30In1 (K1) - 2/3B+
4Seat heating, temperature sensor, leftIn23 (K1) - 4See Heating Pad, Seat (64FL/FR)
5Seat heating, temperature sensor, rightIn23 (K1) - 5See Heating Pad, Seat (64FL/FR)
6Seat heating, rightOutIgnition ON Activate motor1 (K1) - 6B+

PINOUTS REFERENCE CHART

Scheme 392

Scheme 392: Stepping Motor, Air Mixture (222 LH/RH)
Number of windingsPcs2
Resistance, winding 1Pin no.1-3
Ohm100
Resistance, winding 2Pin no.4-6
Ohm100
Stepping frequencyHz200
Power supplyV12

STEPPING MOTOR TECHNICAL DATA

Scheme 393

Scheme 393: Stepping Motor, Air Distribution (221a)
Number of windingsPcs2
Resistance, winding 1Pin no.1-3
Ohm100
Resistance, winding 2Pin no.4-6
Ohm100
Stepping frequencyHz200
Power supplyV12

STEPPING MOTOR TECHNICAL DATA

Scheme 394

Scheme 394: Cabin Temperature Sensor (218)
Power supply, temperature sensor (NTC)Pin no.6 (H10-8)
Ground, temperature sensor, (NTC)Pin no.5 (H10-8)

CABIN TEMPERATURE SENSOR TECHNICAL DATA

Scheme 395

Scheme 395

Supplied with 5V through a 6.8 kohms resistor in the control module.

°C (°F)Kohms
0 (32)26,7-29,3
10 (50)17,5-18,9
20 (68)11,8-12,5
25 (77)9,8-10,3
30 (86)8,1-8,5
40 (104)5,6-6,0

TECHNICAL DATA

Scheme 396

Scheme 396: Mixed Air Temperature Sensor (217 LH/RH)
Power supply, NTCPin no.9
V5
Kohms6.8
Ground, NTCPin no.10

MIXED AIR TEMPERATURE SENSOR TECHNICAL DATA

Scheme 397

Scheme 397

Supplied with 5V through a 6.8 kohms resistor in the control module.

°C (°F)Kohms
0 (32)31.6-33.5
10 (50)19.3-20.4
20 (68)12.2-12.8
30 (86)7,8-8,2
40 (104)5.2-5.5
50 (122)3.5-3.7
60 (140)2.4-2.6
70 (158)1.7-1.8
80 (176)1.2-1.3
90 (194)0.88-0.95

TECHNICAL DATA

Scheme 398

Scheme 398: Solar Sensor (223)
Power supply B+Pin nr.1
GroundPin nr.4
Sensor signalPin nr.2

SOLAR SENSOR TECHNICAL DATA

Scheme 399

Scheme 399

Scheme 400

Scheme 400: Ventilation Fan Control (220)
Control voltageV0-5
Control voltagePin no.2
Power supply B+Pin no.1

VENTILATION FAN CONTROL TECHNICAL DATA

Scheme 401

Scheme 401

Note. The maximum fan current varies depending on the air flow in the heating and ventilation unit and the battery voltage.

Scheme 402

Scheme 402: DC motor, Air Recirculation Flap (38)
Power supply B+V12
Power supply B+, fresh airPin no.6, approx. 10 s after activation
Power supply B+, air recirculationPin no.5, approx. 10 s after activation
Max. current consumption blocked motorMA450
Normal current consumption at "nominal voltage"MA150-230

DC MOTOR TECHNICAL DATA

Scheme 403

Scheme 403: Solenoid Valve, Heat Exchanger Shut-Off Valve (581)
CharacteristicsDe-energized closed
ResistanceOhm43-49
Power supply B+V12
Power supply B+Pin nr.1
GroundPin nr.2

SOLENOID VALVE TECHNICAL DATA

Scheme 404

Scheme 404: Circulation Pump (453)
Power supply B+V12
Max current consumption at "rated voltage"A1,6
Normal current consumption at "rated voltage"A0,8
Power supply B+Pin nr.2
GroundPin nr.1

SPECIFICATION

Scheme 405

Scheme 405: Heating Pad, Seat (64FL/FR)
Nominal consumption at 13 VA12
Resistance, NTCKohms1 ± 5% (at 25C°)
Pad resistanceOhms1.09 ± 0.05 (20C°)

SPECIFICATION

Scheme 406

Scheme 406: Motor, Squab Ventilation Fan (617LH/RH)
Nominal consumption at 13 VA2 2.3-5 Blocked fan

SPECIFICATION

Fault diagnosis strategy for electronic systems

  1. The customer's description of the problem constitutes a basis for the fault diagnosis strategy. If necessary, the customer must demonstrate the trouble on the car to avoid misunderstandings.
  2. In certain cases, the function may be correct. 2.a. Good product knowledge is required to decide this. 2.b. If the function is correct, this must be explained to the customer.
  3. If the function is judged to be faulty, the car should be repaired. Saab's fault diagnosis strategy assumes that the technician is familiar with the customer's description of the problem. So note the customer's complaint and any other observations on the job sheet.
  4. The technician obtains a readout of the diagnostic trouble codes from all systems. A malfunction in one system can often be caused by a fault in another system.
  5. The car may contain diagnostic trouble codes which are secondary faults or which have been incorrectly generated. 5.a. Compare the customer complaint with the symptom description for the various diagnostic trouble codes. WIS has a quick search function for this purpose. 5.b. If the symptom description for a diagnostic trouble code matches the customer's complaint, this diagnostic trouble code is probably caused by the primary fault. Repair as per instructions.
  6. If there is no match with diagnostic trouble codes or symptoms, the technician must diagnose the fault himself. 6.a. Search in WIS under fault diagnosis for symptoms in the system where the fault exists. Also check whether there is a TSB/MI in force. 6.b. If the symptom description in the current system matches the complaint, the right fault diagnosis description has probably been found. Repair as per instructions.
  7. Certain fault symptoms can be remedied by reprogramming the control module. 7.a. Does the customer complaint stem from a known software problem in a programmable control module? 7.b. Reprogram the control module following the instructions in SPS.
  8. If there is no match with diagnostic trouble codes or symptoms, the technician must diagnose the fault himself. Good technical product knowledge is required to solve this type of problem.
  9. A final check must be carried out after the repair.
  10. The car is ready.

Fault symptoms

  1. No system function or poor system function.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.

No function or incorrect function in the ACC panel.

  1. No fan function in the seat.

Type of diagnostics

  1. Continuous
  1. No heat in the seat.
  1. Continuous
  1. No fan function in the seat.
  1. Continuous
  1. No heat in the seat.
  1. Continuous

Perceived temperature in the cabin is too low compared to the set temperature. The temperature in the cabin cannot be regulated on the right-hand side.

Experienced temperature is too low compared to the set temperature. The cabin temperature cannot be adjusted on the right side.

Experienced temperature is too low compared to the set temperature. The cabin temperature cannot be adjusted on the right side.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.

The air distribution does not correspond to set position.

Perceived temperature in cabin too high or too low compared to the set temperature.

The air distribution does not correspond with the illuminated symbol in the ACC window.

Perceived temperature in cabin too high or too low compared to the set temperature.

The air distribution does not correspond with the illuminated symbol in the ACC window.

  1. The cabin is misting up again.
  2. Bad air in the cabin.
  3. Perceived temperature in cabin too high compared to the set temperature.

The ventilation fan cannot be operated from the ACC.

  1. No heat in the seat.
  1. No heat in the seat.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.

Perceived temperature in cabin too high or too low compared to the set temperature.