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I asked a question some time ago about a check light, specifically airbag and seatbelt light. I have since then checked the code with a code reader and removed it. Making the car drive without any alarm for 2 months.

I then had a false start and the light came back on, I will go to check the light again. But I wanted to inquire if this is dangerous for the passenger side or if it poorly created that a false start could create an implausible signal, which may make sense but is very poor design?

false start: I refer to turning the key and stopping before the engine has started properly and it then dies by itself before there is any power for the throttle.

Hope to hear some views, the car is VW polo from 2013.

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  • What's a "false start"?
    – GdD
    Jul 20, 2017 at 6:57
  • @GdD tried explaining what I meant in the question, does it make more sense? When you want to start the car, the starter engine begins, but it has not completely started the car before you release the key, and the engine dies.
    – JTIM
    Jul 20, 2017 at 9:57
  • It's common for warning lights to stay on if you car doesn't start, did they stay on after your car started properly? If not, then there's no issue.
    – GdD
    Jul 20, 2017 at 10:23
  • They did, thats why I can remove them with a code-reader and drive without any issue. But when I have a false start then it comes back on
    – JTIM
    Jul 20, 2017 at 11:04
  • Okay @JTIM, so there's a difference between clearing a code and fixing a problem. If you have recurring warnings you should consider looking into whether there's an actual problem with those systems as they are vital to safety. If could be an instrumentation problem too, I suggest you edit and add the make and model of your car and any other issues you've had if you want to get answers.
    – GdD
    Jul 20, 2017 at 11:07

2 Answers 2

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An "implausible signal" is one that doesn't make sense in the context of the system -- for example a signal voltage that is outside of the normal range of a sensor. This could be an early sign of a failing component but in your case it may also be due to the voltage drop that happens normally during a start.

Many electronic components will behave in unpredictable fashion when their supply voltage is low. During a failed start the voltage may go lower than expected. It is also possible that after 14 years the quality grounds or the resistance of connectors in the airbag system have deteriorated and are contributing to out of spec voltages.

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  • Thank you for your answer, sorry edited the question, it is only 4 years old, (confused the dates with my old car). That is what I am wondering I just see it as poor design, I mean the system knows that it was limited power. I have decided to clear the code and play with the code clearer and false starts to assess if there is a causality.
    – JTIM
    Jul 21, 2017 at 6:14
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I've frequently seen this fault logged by Volkswagens cars that have a poor condition battery, or a battery that has become discharged.

The best probable explanation I can come up with is that the "false start" you described caused a drop or spike in voltage (or even removed voltage from the supply line, depending on what you did with the ignition key) right at the point that the airbag controller was powering up and performing its self-diagnostic.

My advice would be to clear the fault and consider having the battery condition checked by your local garage.

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