Technical Error Code 1688 2nd Idle learn (Phonic relearn)

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Technical Error Code 1688 2nd Idle learn (Phonic relearn)

mb69rolls

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I'm usually the one asking the questions, but for once I may have some useful information. It may well be that many people know this method, but for those that don't, it took me a lot of trawling around the web before I found the answer, so I hope it helps someone.

After an exuberant wheelspin in a 2004 1.4 Idea (probably never been subjected to that in it's life) the EML came on with a somewhat dramatic "Engine Failure" warning. after plugging in my new Autel AL301 code reader, I came up with the code P1688 which I discovered was "2nd Idle relearn". I tried clearing it but it wouldn't go away. All I could find in relation was a method involving switching on the ignition for 1 minute, off for another minute, then start up without touching the throttle, and leave until the fan kicks in, then repeat the first 2 steps. The method had been reposted around several sites, but made no difference.

Then I stumbled upon the following. The method required is called a "Phonic Relearn" and it is simplicity itself.

1.Start the car, and wait until the temp gauge is halfway, or until the fan starts if you have no gauge.
2. Rev to 5000 rpm for 3 seconds and allow to return to idle (repeat 2 more times)
3.Switch off.

The EML was still on, but I could now turn it off with the reader, and it then stayed off. I have read that once the cause of the EML has been fixed, the light will go off on it's own after a number of restart cycles.

As I said, this worked on my 2004 Idea petrol, but it sounds like it could work for several models, so maybe there's a better place for this post.

Cheers all.
 
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