Fault Code 1578
Fault code 1578Indicator light (passenger's airbag OFF display)
Diagnostic conditions
- Ignition on
- Internal function test on airbag triggering unit
Possible cause of fault
- Short circuit to B+ (based on the wiring of pin 70 of airbag triggering unit and pin 2 of indicator light)
- Open circuit/short circuit to ground (based on the wiring of pin 70 of airbag triggering unit and pin 2 of indicator light)
- Fuse F26 (10A) in fuse carrier at left of dashboard faulty
- Indicator light faulty
- Airbag triggering unit incorrectly coded when locked
- Triggering unit for airbag faulty
Affected pins
- Airbag triggering unit Pin 70
- Indicator light: Pin 2
- Fuse F26 (10A) in fuse carrier at left of dashboard
Diagnosis/troubleshooting
NOTE: When the ignition (terminal 15) is switched on, a control phase is run in order to check the activation/deactivation of the passenger's airbag ignition circuit, including the airbag switch and the indicator light (passenger's airbag OFF display). This control phase is evident by the fact that the indicator light lights up for approx. four seconds (but not when the airbag switch is OFF, i.e. the passenger's airbag is deactivated). If implausible statuses are detected in the passenger's airbag ignition circuit, the indicator light starts flashing and the airbag warning light may also come on. If such a situation arises, read out the fault memory and work through the diagnosis/troubleshooting instructions.
NOTE: A battery voltage of between 11.4 and 14.5 V is required for the following troubleshooting procedure. This must be checked and provided, if necessary. Voltages as well as components or fuses (input side) must be guaranteed on the vehicle electrical system.
