Fault Code 1218

Fault code 1218

Ignition circuit, passenger's side airbag

Conditions for diagnosis
- Ignition on
- Internal function test on airbag trigger unit

Possible cause of fault
- Upper limit exceeded (based on resistance of passenger side airbag and wiring between airbag trigger unit and passenger side airbag)
- Lower limit not reached (based on resistance of passenger side airbag and wiring between airbag trigger unit and passenger side airbag)
- Short circuit to positive
- Short circuit to ground
- Passenger side airbag faulty
- Airbag trigger unit faulty

Affected pins
- Airbag trigger unit: Pin 45 and Pin 46
- 3-pin plug connection passenger side airbag (under the passenger seat): Pin 1 and Pin 2
- 2-pin plug connection passenger side airbag (behind the 3-pin plug connection towards the side airbag): Pin 1 and Pin 2

Diagnosis/troubleshooting

WARNING:
Risk 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 in place of the airbag units.

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

NOTE:
The wiring harness between the airbag trigger unit and the side air-bags in the seats has a number of disconnection points which must be considered first as possible causes of the fault. Before actually replacing the airbag trigger unit, the following disconnection points must be checked with the ignition switched off for correct contacts, possible corrosion or damage:
- First disconnection point under seat area of drivers and passenger seat (3-pin cutoff connection with short circuit bridge)
- Second disconnection point between 3-pin cutoff connection and the side airbag (2-pin cutoff connection with short circuit bridge)
- Third disconnection point directly on side airbag (only inspect this visually (this involves dismantling the seat - should only be done in exceptional cases) - never disconnect plug)

Additional airbag tester, Porsche set No. 169