Air Bag Systems: Application and ID

Airbag

Introduction - airbag

Airbag system 0101

Cayenne as of model year 2003

NOTE: The airbag triggering unit is part of the standard equipment of the Cayenne. There are two types of triggering unit: A 'RoW variant' (Rest of World variant) and a 'non-RoW variant'. The diagnosis/troubleshooting instructions given below can be used for both variants. The difference, from the point of view of diagnostics, is that the fault codes 1228 and 1578 cannot occur for the airbag triggering unit in the 'non-RoW variant'. In addition, various menu and selection functions in the 9588 Porsche System Tester II are not used. The following components are not part of the component arrangement for the 'non-RoW variant': Airbag switch and indicator light (passenger's airbag OFF display).

NOTE: The airbag system of the Cayenne includes a system check, which runs in the background and is activated when the ignition is switched on. In comparison to other model ranges, the airbag warning light remains on after the system check is complete (only if the ignition is still on and the engine is not started) and only goes out again when the engine is started and no faults are detected in the airbag system check.

General instructions/safety instructions
The following points must be observed during vehicle diagnosis:
- After the battery is connected, volatile memories must be reprogrammed. In the case of radio coding and tuning, the customer must be informed of decoding and the deleted tuner memory.
- After troubleshooting or repairs, erase the fault memory with the 9588 Porsche System Tester II and carry out a test drive.
- After the test drive, read out the fault memory with the 9588 Porsche System Tester II again.

DANGER:
Danger of injury through triggering of driver's airbag.
- Never hang the 9588 Porsche System Tester II over the steering wheel.

WARNING: Observe safety regulations when working on the airbag system --> Rep. Gr. 69; Safety regulations for vehicles with airbag and belt tensioner.

WARNING:
Danger of injury and damage to property as a result of incorrect handling of airbag units.
Please observe the following points:
- Inspection and assembly work must only be carried out by specialist staff.
- After the battery is disconnected, assembly work or work on the vehicle with a hammer or similar tools must not be started until after a waiting period of 1 minute.
- This is necessary in order to interrupt the power supply to the airbag system and to ensure it is not triggered accidentally.
- Airbag units must be fitted immediately after being removed from their storage location.
- Airbag units must never be left lying around unattended.
- If work is interrupted, airbag units must immediately be locked away again.
- Airbag units must not be allowed to come into contact with grease, oil, cleaning agents or similar substances.
- Airbag units must not be exposed to temperatures above 90 °C.
- Airbag units and control units which have fallen from a height of more than 0.5 m must not be installed.
- Additional linings, stickers or similar must not be attached to the steering wheel or in the vicinity of the passenger's airbag.
- Changes must not be made to the wiring or the components of the airbag system.
- The battery must always be disconnected before starting straightening and welding work with an electrical welding unit.

WARNING:
Danger of injury and damage to property as a result of incorrect handling of airbag units.
Please observe the following points:
- The airbag units are pyrotechnical items in hazard class T 1.
- Handling, transport and storage of these units must conform to the explosives legislation.
- The listed statutory requirements refer to the Federal Republic of Germany.
- The relevant valid regulations must be observed in all other countries.
- The commencement of work with pyrotechnical items must be reported 14 days in advance to the Trade Supervisory Office (responsible authority).
- Airbag units must only be dispatched in transport packaging officially approved for that purpose.
- Airbag units must not be transported with other hazardous goods.
- Internally, they must always be transported in the luggage compartment or cargo hold of a vehicle using the transport packaging referred to above.
- They must not be transported in the passenger's compartment.
- Airbag units must be stored in accordance with the second ordinance of the explosives legislation.
- This ordinance stipulates that small quantities of materials and items may be stored at certain locations without special storage approval.
- According to the Explosives Storage Directive of August 1997, these quantities are 10 kg (net) max. in a work room and 100 kg (net) max. in a storage room in the case of Class T 1 pyrotechnical items.

WARNING:
Danger of personal injury if the drive link test is carried out when the vehicle is in motion.
- Never carry out the drive link test when the vehicle is in motion.

The following conditions must be observed when carrying out the drive link test:
- The drive link test must always be carried out on a stationary vehicle in a workshop with sufficient commercially available tools. The driver's seat must then be partially removed in order to re-activate the cut-out relay. Only then can the engine be re-started.

WARNING:
Danger of injury due to the risk of fire in the event of short circuits in the wiring harness or of emerging fluids when the cut-out relay is actuated (for disconnecting battery).
- The cut-out relay (for disconnecting battery) must only be actuated by trained and authorised staff.
- Damage, abrasions or squashed wires in the wiring harness must be located and either repaired or replaced in accordance with Porsche guidelines.
- Short circuits to B+, short circuits to ground and open circuits in the entire wiring harness must be eliminated and, if necessary, repaired or replaced in accordance with Porsche guidelines.
- Mechanical components must not be damaged in any way that could cause locally emerging fluids to ignite in the event of a short circuit.

WARNING:
Danger of injury as a result of malfunctions (loose contacts) in airbag modules when unplugging module connectors and belt tensioner plugs.
- When installing and removing airbag modules and belt tensioners, the plug connections provided must be disconnected using an integrated short circuit bridge.
- Never pull off plugs connected directly to airbag modules and belt tensioners.
- Do not remove wiring harnesses from other vehicles in order to connect these to 'third-party' airbag modules or belt tensioners.

WARNING:
Danger of injury and damage due to unusual vehicle handling when plugs or components are disconnected.
- Never disconnect plugs when the vehicle is in motion or drive the vehicle with plugs disconnected.
- Drive only with all parts fully installed and connected.

WARNING:
Danger of injury if vehicle is driven with special tools in place (commercially available tools included).
- Never drive with special tools or commercially available tools attached instead of the airbag units.

CAUTION:
Danger of damage due to improper handling of batteries and control module plug connections.
- Never disconnect battery terminals with engine running.
- Never start engine unless battery terminal clamps are connected securely.
- Never pull off or push on plug connections for the control units or other electronic components when the ignition is switched on.
- Always disconnect the negative terminal of the battery and pull off all plug connections to the vehicle electrical system control unit when carrying out welding work on the vehicle.

NOTE: The airbag warning light in the instrument cluster lights up to indicate sporadic faults (loose contacts, etc.) in the airbag ignition circuits. The airbag warning light remains on even when the fault is no longer present. It can only be turned off by reading out the fault memory, eliminating the cause of the fault and then erasing the fault memory, provided there are no other faults in the system. This means that even faults that only occur briefly are reported to the driver and stored in the fault memory.

NOTE:
The wiring harness between the airbag triggering unit and the driver's airbag unit has a number of disconnection points, which must be considered as most likely causes of the fault. The following disconnection points must be checked for correct contacts, possible corrosion or damage with the battery disconnected for at least one minute before actually replacing the airbag triggering unit as a last resort:
- First disconnection point in front of spiral spring (behind top steering column switch)
- Second disconnection point in steering wheel pod
- Third disconnection point directly at driver's airbag unit (only inspect this visually - never disconnect plug.)

NOTE: Never disconnect plugs that are connected directly to airbag modules and belt tensioners because these have been connected at a defined contact pressure in order to prevent a malfunction due to the plug becoming loose during the life of the vehicle. The plug connections (mostly 3-pin) provided for this purpose must be disconnected using an integrated short- circuit bridge.

NOTE:
The wiring harness between the airbag triggering unit and the side airbags in the seats has a number of disconnection points, which must be considered as most likely causes of the fault. The following disconnection points must be checked for correct contacts, possible corrosion or damage with the battery disconnected for at least one minute before actually replacing the airbag triggering unit as a last resort:
- First disconnection point under seat area of driver's and passenger's seat (3-pin cut-off connection with short circuit bridge)
- Second disconnection point between 3-pin cut-off connection and the side airbag (2-pin cut-off connection with short circuit bridge)
- Third disconnection point directly at side airbag (only inspect this visually (this involves disassembling seat - should only be done in exceptional cases) - never disconnect plug.)

General information on the fault memory

NOTE:
- A period of 10 seconds is required to enable the triggering unit to identify all faults in the system. In order to guarantee that every possible fault source is checked during the vehicle test, the ignition must be switched on for at least 10 seconds.
- The fault memory must be cleared following a fault in the airbag system and after it has been remedied.
- The replacement of a component must be noted in the Guarantee and Maintenance booklet. To do this, attach the documentation number in a free panel intended for that purpose. The documentation number is attached to the replacement part as a tear-off sticker.

NOTE:
If the fault memory is cleared, the ignition must be switched off and then on again in order to check the fault path. Only in this way is another self-test carried out.
The following components must be removed and replaced following an accident in which the airbag system was triggered:
- Contact unit
- Triggered airbag unit(s)
- Triggered belt tensioner unit(s)
The triggering unit must be replaced after the airbag is triggered for the third time.

Fault code setting conditions
Fault codes can be set in several circumstances, e.g.:
- Battery disconnected
- Plug connections disconnected
- Faulty coding
- Power failure
- etc.
In these circumstances, no fault is present in the system and the fault memory must be erased.

Troubleshooting procedure
Troubleshooting can only be performed when the fault is present. In other words, specific troubleshooting can only be performed in accordance with instructions (given under Diagnosis/troubleshooting for each fault code) if the entry has the status 'present' in the fault memory.
If the fault is currently 'not present', please check the following:
- Diagnostic conditions are met
- All plug connections and ground points of the affected current path are OK.
- View the fault frequency counter in the 9588 Porsche System
Tester II using the fault memory Info key [F8] under 'Extended fault memory' and try to reach conclusions about eliminating any loose contacts in the system

Diagnostic conditions

NOTE:
The fault can only be identified if the requirements listed under 'Diagnostic conditions' are met. For this reason, the specified procedure must be observed after a fault is repaired:
1. Clear fault memory.
2. Satisfy the requirements listed under 'Diagnostic conditions'.
3. Read out fault memory again

Possible causes of fault

NOTE: The 'possible causes of fault' that are responsible for the fault are listed here. Please note that in certain circumstances further faults can be stored in the fault memory after troubleshooting (e.g. if plugs are disconnected). After carrying out repairs, read out the fault memory of all control modules and erase any faults.

Diagnosis/troubleshooting

NOTE: The fault memory Info key [F8] on 9588 Porsche System Tester II can be used to access the 'extended fault memory'. The following information can be displayed:

Fault type
The following fault types are possible:
- No display
- Upper limit value exceeded
- Lower limit value not reached
- Mechanical fault
- No signal/communication
- No or incorrect basic setting/adaptation
- Short circuit to B+
- Short circuit to ground
- Implausible signal
- Open circuit/short circuit to ground
- Open circuit/short circuit to B+
- Open circuit
- Electrical fault in electric circuit
- Please read out fault memory
- Faulty
- Cannot be checked now

Fault status
The following status types are possible:
- Present
- Not present
This information should be saved using the Save key [F4] and printed out.

NOTE:
Visual inspection: During troubleshooting, please check first that the affected pins on the airbag triggering unit plug connection are neither damaged nor corroded. The wiring and plugs of the affected components must also be checked for external damage and correct contact. Repair damaged or corroded pins if possible, otherwise replace affected pins. Repair or replace damaged wiring in accordance with Porsche guidelines.

NOTE:
Battery voltage: A battery voltage of between 11.4 and 14.5 V is required for troubleshooting. This must be checked and provided if necessary. Supply side voltages to components and fuses must be guaranteed on the vehicle electrical system.