U1700 - CAN communication fault with the airbag control unit airbag control unit fault

What does error code U1700 mean in the airbag control unit?

Error code U1700 reports a CAN communication fault with the airbag control unit, meaning a disrupted connection via the vehicle network, in which control units exchange data with one another. The data link via the CAN bus to the airbag control unit is affected; the unit stores the fault in the fault memory and switches on the airbag warning light, which points to the restraint system (SRS).

The airbag control unit is part of the restraint system and controls the airbag modules and seatbelt pretensioners. If communication over the CAN bus is disrupted, data between the control unit and the rest of the vehicle is not transmitted as intended.

How do you recognise error code U1700?

Error code U1700 shows up as a permanently lit airbag warning light and is stored in the fault memory of the airbag control unit. The fault cannot be permanently erased, and it is read out with a diagnostic tool that you connect to the vehicle so that the code becomes visible.

Whether the code U1700 is actually stored in the fault memory can only be shown by reading it out with a diagnostic tool. The warning light alone is not sufficient for this.

What causes error code U1700?

In the case of a communication fault, possible causes include the power supply, the data line with its plug and the airbag control unit itself. The code alone cannot tell which cause applies, because it only reports the communication fault and does not record where in the network the disruption occurs.

• The airbag control unit does not respond, for example because it is defective or locked.
• The power supply to the control unit is disrupted.
• The data line is damaged, or a plug in the data path is not properly connected.

For the check, it is therefore important first to establish whether the control unit receives power and whether the data line and plug are in order.

In which vehicles does error code U1700 occur?

Error code U1700 is known on Fiat vehicles, specifically on the Fiat 600 1st generation, Fiat Doblo 223 facelift, Fiat Doblo K9, Fiat Grande Panda 1st generation, Fiat Scudo K0 and Fiat Ulysse K0. The list is not complete, and for other vehicles the meaning of the code may differ.

To find out whether the code occurs on your vehicle, clarify the make, model and series. What matters in the end is the reading out on the vehicle, because only then can it be seen whether the code is actually stored in the fault memory.

How is error code U1700 resolved?

Error code U1700 is resolved by having the fault memory read out with a diagnostic tool and narrowing down the cause step by step, starting with the data line and plug. If the control unit is the cause, it is sent to Airbag24 after removal, via a repair order created online, for repair.

Have the plug, data line and power supply checked first at a specialist workshop. Safety note: work on the airbag system should be left to qualified professionals.

If the control unit itself is affected, for example because it does not respond, first disconnect the battery before removing the unit. Then create a repair order online and send the unit to Airbag24. Checking, repairing and testing usually take 3–4 working days.

The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.