DF002 - Supply voltage unstable (too low or too high) airbag control unit fault

What does error code DF002 mean in the airbag control unit?

Error code DF002 reports that the supply voltage of the airbag control unit is unstable, either too low or too high. The power supply of the restraint system (SRS) is therefore affected, and the control unit stores this fault in the fault memory and switches on the airbag warning light so that the problem is shown in the vehicle.

The fault therefore does not concern a single airbag module or sensor, but the power supply of the control unit itself. The control unit needs a steady voltage, and the code shows that this voltage is not correct.

For classification, it is therefore important to first confirm that the voltage in the vehicle is correct. Only then can you judge whether the control unit itself is affected.

How do you recognise error code DF002?

You recognise error code DF002 by the airbag warning light staying on permanently and by the entry in the fault memory of the airbag control unit. The code is stored there, cannot be permanently erased and is read out with a diagnostic tool that retrieves the control unit's fault memory via the diagnostic interface.

A permanently lit airbag warning light alone does not yet tell you which fault is present.

Only reading out the fault memory shows the code DF002, and it is this entry that distinguishes it from other faults in the airbag system. For diagnosis, the fault memory is therefore more important than the warning light alone.

What causes error code DF002?

Error code DF002 occurs when the supply voltage of the airbag control unit is unstable, either too low or too high. Possible causes include a weak battery, voltage spikes when jump-starting the vehicle, connectors and wiring of the power supply, and the control unit itself, although the cause only becomes clear on testing.

• A weak battery that does not hold the voltage steady
• Voltage spikes when starting with jump leads
• Corroded or damaged connectors and wiring of the power supply
• Aged electronic components, solder joints, moisture or corrosion inside the control unit

Which cause applies only becomes clear on testing. So do not assign the fault to the control unit too quickly, as connectors and wiring are also possible causes.

In which vehicles does error code DF002 occur?

Error code DF002 is known on Renault vehicles, including the models Renault 4 E-Tech, Clio VI, Espace VI, Scénic V, Twingo IV and Twizy I. The list is not complete, and on other vehicles the meaning of the code may differ.

Whether a particular vehicle shows this code can only be established by reading out the fault memory with a diagnostic tool. The list is therefore a guide and does not replace this check, even where make and model match.

How is error code DF002 resolved?

Error code DF002 is resolved by first reading out the fault memory with a diagnostic tool and then narrowing down the cause step by step. If the cause lies in connectors or wiring of the power supply, have these checked thoroughly at a specialist workshop before taking further steps.

Work on the airbag system should be left to qualified hands. If the cause lies in the airbag control unit itself, disconnect the battery first and then remove the control unit.

Then create a repair order online and send the unit to our workshop in Berlin. 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.