0X930901: Driver Stage 1 Ground Short

Circuit fault

What 0X930901 means

Stage 1 is the first of the two inflator charges in a dual stage driver airbag. The ACSM keeps a monitored loop running out to that inflator and back, and it watches the voltage on both wires. When one of them drops to chassis potential, the module knows the loop has found ground somewhere it should not, and it writes 0X930901.

A short to ground is a specific failure pattern, and it points you at places where the wiring can touch metal. Inside the steering column that means the clockspring ribbon, which flexes every time the wheel turns and can wear through against the housing. Outside the column it means the harness run under the dash, where a sharp bracket edge or a pinched section does the same thing.

Common causes

• A worn or cracked clockspring ribbon rubbing through to the column housing
• Harness wire pinched against a bracket or panel edge under the dash
• A driver airbag pigtail crushed when the airbag was reinstalled into the wheel
• Water in the steering column or lower dash creating a path to ground
• Damaged insulation from a previous repair, aftermarket steering wheel, or wheel controls wiring
• A shorted inflator winding inside the airbag module itself

Crash data or hardware fault?

Read this as a live electrical condition, not a stored crash record. The ACSM measures the loop continuously, so the code represents what the wiring is doing at the moment of the test and it clears once the short is gone. Deployment data is a different entry entirely. It is written when the airbags fire and it stays in the module until the module is reset or replaced.

Does our reset clear it?

A short to ground is a wiring repair, not a reset job. If you clear the module and hand the car back, the ACSM finds the same short during its next check and the light returns before the customer leaves the lot. Trace and repair the short first. When the BMW was wrecked and the module also holds crash data behind this code, mail the ACSM to us after the repairs and we clear that stored record.

Which makes throw it

0X930901 is a BMW code. The hex numbering belongs to BMW diagnostic software, and the code reads the same across BMW models using an ACSM restraint controller.

What to do next

Unplug the driver airbag at the wheel and see whether the code changes character. If the short disappears with the airbag disconnected, the problem is in the airbag or its pigtail. If it stays, the fault is upstream in the clockspring or the column harness, and the clockspring is where most of these end. We stock genuine OEM BMW driver airbags and clocksprings if the test points to either one. Related codes: 0X481716, 0X930902, B1361.