Airbag ECU code 31 - what does it really mean?

[ajuniper]

Thanks for the prompt reply.

Is there any chance that the fault code could be induced by e.g. a wiring or earthing fault? I'd hate to go about sourcing a replacement ECU only to find that the problem wasn't in the ECU at all.

How likely is it that having the ECU "reset" will be successful? Do these ECUs suffer from transient faults or is this code likely to be terminal?

thanks
Andy

[CTScott]

Originally Posted by ajuniper

Thanks for the prompt reply.

Is there any chance that the fault code could be induced by e.g. a wiring or earthing fault? I'd hate to go about sourcing a replacement ECU only to find that the problem wasn't in the ECU at all.

How likely is it that having the ECU "reset" will be successful? Do these ECUs suffer from transient faults or is this code likely to be terminal?

thanks
Andy

You can actually try resetting it yourself using the procedure below. I have never heard of anyone having that particular fault, so it is not common. As for being a wiring or ground fault, I would suspect that more than just that ECU would be having issues if it were.


For MK1 Yaris built in France after 11-2002, the procedure to reset the SRS light is:




1. Jump the CG and TC pins (Shown in the post above about reading the codes).

2. Turn the ignition to ON

3. Remove the jumper within 10 seconds after the airbag light begins to flash to show the stored codes.

4. Within 3 seconds of disconnecting the jumper the airbag light should light up.

5. Within 2 to 4 seconds after the airbag light comes on, reconnect the jumper between CG and TC.

6. Within 2 to 4 seconds after reconnecting the jumper the airbag light will go off.

7. Within 2 to 4 seconds after the airbag light goes off, disconnect the jumper between CG and TC.

8. Within 3 seconds of disconnecting the jumper the airbag light should light up.

9. Within 2 to 4 seconds after the airbag light comes on, reconnect the jumper between CG and TC.

10. Within 2 to 4 seconds after reconnecting the jumper the airbag light will go off.

11. 1 second after the airbag light goes off the light will flash to indicate the code cleared

12. Turn the ignition off and if more than one code was reported, repeat the procedure to clear the additional codes.


This procedure can be tricky to do, so I recommend creating a jumper with a momentary normally open push button switch, so that you can simply press the button at the appropriate time, rather than having to keep reaching under the dash to make or break the connection. This switch assembly is simply a switch connected to two pieces of wire, with the other ends stripped. If the wire used will not stay seated in the connector, strip a bit more insulation and fold the tip of the wire in half to create a larger "terminal" to insert into the diagnostic connector.