A603 - Passenger airbag stage 1 firing circuit, short to positive airbag control unit fault

What does error code A603 mean in the airbag control unit?

Error code A603 reports a short to positive on Peugeot vehicles in the ignition circuit of the first stage of the passenger airbag, that is, in the circuit through which the airbag is triggered. The airbag control unit stores this fault in the fault memory and switches on the airbag warning light in the vehicle.

The ignition circuit connects the airbag control unit to the passenger's airbag module. If there is a short to positive there, the first stage is disrupted, and the control unit holds the fault in the fault memory.

A short to positive means that there is a connection to the positive supply line where it should not be.

How do you recognise error code A603?

You recognise error code A603 by the airbag warning light staying on permanently and the code being stored in the fault memory of the airbag control unit. The entry cannot be permanently cleared, and it only becomes visible when the fault memory is read out with a diagnostic tool that displays the code.

The warning light alone does not reveal which fault is present. Whether the code is actually present in your vehicle is shown by the readout at a specialist workshop.

What causes error code A603?

Error code A603 is caused by faults in the ignition circuit of the first stage of the passenger airbag, where a wire or contact touches the positive line. The short can occur at several points in this circuit, because wiring, connectors, the airbag module and the control unit all belong to it.

• The airbag control unit itself, for example with aged components or faulty soldered joints
• The passenger's airbag module, if it is damaged in the ignition circuit
• A damaged wiring harness whose insulation has chafed through and touches the positive line
• A loose or corroded connector in the ignition circuit

Which of these points is affected is only determined by checking the vehicle.

In which vehicles does error code A603 occur?

Error code A603 occurs on Peugeot vehicles, specifically on the models Peugeot 206 I (206+), Peugeot 306 Break I, Peugeot 405 Break I Facelift and Peugeot 5008 III. For these Peugeot series the meaning of the code is known, and the fault can be checked on your own vehicle with a diagnostic tool.

The list is not complete, and on other vehicles the meaning of error code A603 may differ. Whether a specific vehicle is affected is only shown by a readout of the fault memory.

How is error code A603 resolved?

You resolve error code A603 by having the fault memory read out and the connector, wiring and passenger airbag module checked at a specialist workshop. Only if no fault is found there does the airbag control unit itself come into consideration and have to be sent in for repair.

The check begins in the ignition circuit, that is, with the wiring for contact with the positive line, the connectors and the airbag module. Work on the airbag system should be left to qualified professionals.

If the cause lies in the control unit, first disconnect the battery and then remove the airbag 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.