A L L Diagnostic Trouble Codes ( DTC ): Testing and Inspection
DIAGNOSIS
The airbag system is monitored continuously by a diagnosis unit in the control unit. Any fault which may occur is indicated by the word airbag" in the instrument cluster.
When the ignition is switched on, the airbag annunciator remains lit for approximately 5 seconds before going out. When the engine is started the annunciator lights up again for approx. 5 seconds. Any further response of the annunciator indicates a defect in the system. The fault can be output via the airbag annunciator when an excitation signal is applied to the diagnosis input line (application of an earth signal). For this purpose, an improvised tool must be used to input a code.
Note
The control unit needs a period of 2 minutes to detect all the faults in the system. To assure that every possible source of trouble is tested in a diagnosis, the ignition must remain switched on for at least 2 minutes.
1 Wire (commercially available) approx. 0.5 m long
2 Crocodile clip
3 Pushbutton (e.g. limit switch for tilting sunroof, use closing function)
4 Plug receptacle [171.971.998 B]
5 Round plug N [017.589.4]
6 Flat plug 6.3 x 0.8 [111.971.959]
Connect the round plug to pin 2 of the plug receptacle.
1. Switch off ignition.
2. Connect improvised tool.
3. Press switch.
4. Switch ignition on.
5. Release switch 3 seconds after ignition is switched on.
The flashing code then runs off as described below:
1. 5-second lamp test.
2. Flashes 1 or more times, depending on number of faults.
3. 3 seconds - start for fault code.
4. Flashes 1 to 4 times, depending on group in fault table.
5. Flashes 1 to 4 times, depending on line in fault table.
6. Flashes 1 to 4 times, depending on column in fault table.
7. Flashes 1 or 2 times
1 = Short-time fault
2 = Long-time fault
8. 3 seconds - start for fault code of a further fault.
Light remains on - end of interrogation.
The flashing code interrogation can be repeated as often as desired.
The flashing pulses must be noted and the corresponding number must be read from the following table; e.g. flashing code 1 - 3 - 3 - 2 means the number 29 and signifies a long-time fault.
1 - Group
3 - Line
3 - Column
2 - Long-time fault
Fault table for lamp codes
The fault can be found in the following fault code table with the help of the number found in the fault table for lamp codes; e.g. for number 29: ignition pill circuit 3 - break.
Hex-Code 01-12:
Hex-Code 13-26:
Hex-Code 27-34:
Fault Code Table
Ignition pill circuit 1: drivers airbag
Ignition pill circuits 2 and 3: passengers airbag
The following jobs must be performed when a fault occurs:
Faults 01 to 06
- Replace left or right front sensor.
Faults 07 to OE
- Check front sensor with ohmmeter
1. Ohmmeter to terminals 1 and 2 Reading: 10 kOhm
2. Ohmmeter to terminals 2 and 3 Reading: 0 Ohm
- If the readings are obtained, erase fault memory. If fault still present, replace control unit.
- If the readings are not obtained, replace front sensor.
Fault 11 or 12
- Check front sensor plug connection for correct tightness of plug contacts and correct tightness of plug connection.
- Check front sensor with ohmmeter (see faults 07 to 0E).
- If ohmmeter shows infinity Ohm for point 1 or 2, replace the front sensor. If the readings are obtained, replace control unit.
Fault 13 or 14
- Check front sensor with ohmmeter (see faults 07 to 0E).
- If front sensor is OK, replace control unit.
Faults 17 to 1A
- Replace control unit.
Faults 1B, 1E, 21, 24
- Try installing new contact unit.
- Turn On ignition.
- If fault still present, try installing airbag unit.
- If fault still present, replace control unit.
- Erase fault memory, if applicable, after re-assembling.
Faults 1C, 1D, 1F, 20, 22, 23, 25, 26
- Try installing new airbag unit.
- Turn on ignition.
- If fault still present, replace control unit.
Fault 27
- Check tightness of plug connection to airbag unit.
- Check tightness of plug connection to contact unit.
- If plug connections are tight, try installing new contact unit.
- Turn on ignition.
- If fault still present, try installing new airbag unit.
- Turn on ignition.
- If fault still present, replace control unit.
Fault 28 or 29
- Check tightness of plug connection to airbag unit.
- If plug connection is OK, try connecting new airbag unit. If fault still present, replace control unit.
Fault 2A
- Try connecting new airbag unit. If fault still present, replace control unit.
Fault 28 or 2C
- Try connecting new airbag unit. If fault still present, replace control unit.
Fault 20
- Replace contact unit.
- Check plug contacts of plug connections to airbag unit and contact unit for corrosion.
- If contacts are in good condition, try connecting new airbag unit. If fault is still present, replace control unit.
Fault 2E or 2F
- Check plug contacts at plug connections to airbag unit for corrosion.
- If contacts are in good condition, try connecting new airbag unit. If fault still present, replace control unit.
Faults 30 and 31
Central warning lamp and belt symbol still light up after failure of the airbag sign.
- Remove and check control lamp, replacing if necessary.
- Check wiring harness for damage, replacing control unit if necessary.
Fault 32
- Replace control unit.
Faults 33 and 34
Fault indications 33 and 34 are displayed only after an accident with airbag activation. In this case, all components must be replaced.
The fault memory has to be erased after a disturbance in the airbag system and its elimination.
Erasing Fault Memory
1. Turn off ignition.
2. Apply locally made tool on test plug.
3. Press switch button.
4. Turn on ignition. Switch remains pressed 5 seconds, is then released 5 seconds and pressed again 5 seconds.
Note: The precision of a clock with a seconds needle is sufficient.
5. Turn off ignition.
6. Check whether fault memory is erased. Turn on ignition for this purpose. Airbag sign light must go out after 5 seconds.
Note:
The exchange of a component must be entered in the service booklet. This is done by pasting the documentation number label in a provided field. Documentation numbers are provided on replacement parts as tear-off labels.
The following components must be removed and replaced after an accident with activation of the airbag system.
- Control unit
- Both front sensors
- Contact unit
- Both airbag units
Removed parts must be sent to Porsche or the respective importer. Airbag units may only be shipped in officially be approved packaging.