Fault Code 1738

Fault code 1738

Airbag sensor (driver's)

Diagnostic conditions
- Ignition on
- Internal function test on airbag triggering unit

Possible cause of fault
- Implausible signal (incorrect airbag sensor installed)
- Open circuit (based on wiring between airbag triggering unit and airbag sensor or the airbag sensor itself)
- Electrical fault in electric circuit (based on wiring between airbag triggering unit and airbag sensor; probably a short circuit to B+ or a short circuit to ground)
- Faulty (airbag sensor is faulty)
- Airbag triggering unit faulty

NOTE: The six installed sensors have an identical design of wiring harness contact plug. Only the mounting points are different. The airbag sensors under the driver's and passenger's seats have a thread for fastening, while all the other sensors only have a non-threaded bushing. There is therefore a risk of confusing the sensors on the rear wheel arches with the sensors on the lock mount. If these are confused accidentally, the 9588 Porsche System Tester II will display this fault code along with the fault type 'implausible signal'. Given this, it is always important to ensure that the correct sensors are installed at the correct position. This is because they have different sensitivity settings.

Affected pins
- Airbag triggering unit: Pin 78
- Airbag sensor (driver's): Pin 2 (via additional disconnection point)

Diagnosis/troubleshooting