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Audi TT 1.8T BAM - Code 16885 / P0501 vehicle speed senor implausible #

Posted by Nick Evans on November 26, 2014, 2:48 pm

Year of Manufacture *: 2002
Engine Size and Code *: 1.8T BAM
( Optional ) Scanner Used: Verus

I have an audi TT with fault code 16885 in the pcm, which the description is vehicle speed sensor implausible signal.

I have scoped the speed signal upto the instrument pack with the following wave form.

And this is the scope trace coming out of the instrument pack going to the pcm.

Is anyone able to verify if this is correct or not, I have sent the I/P off for repair & it has come back as good but im suspicious as every thing else tests ok.

Thanks
Nick

Re: Audi TT code 16885 / p0501

Posted by Tony Ludford <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5539' width='330' height='300' border=0 style='border:none;'> on November 26, 2014, 6:04 pm, in reply to "Audi TT code 16885 / p0501"
Tony Ludford

Does the speedo work okay? Any DTC's in instruments?

If it's only the pcm that's quoting that fault code then perhaps it would be worth checking the speed signal there too?

Re: Audi TT code 16885 / p0501

Posted by Nick Evans on November 27, 2014, 8:13 am, in reply to "Re: Audi TT code 16885 / p0501"
Edited by board administrator November 27, 2014, 12:47 pm

Yes the speedo works fine as does the rest of the dash, my concern is the low voltage of the output from the dash to the pcm.

I have scoped it at the dash & at the pcm, I have also removed the wire from the pcm incase that was pulling it down but still have the low voltage waveform.

Re: Audi TT code 16885 / p0501

Posted by Alan Ganter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3444' width='330' height='300' border=0 style='border:none;'> on November 27, 2014, 9:03 pm, in reply to "Re: Audi TT code 16885 / p0501"
Alan Ganter

Can you provide the ECU with a variable PWM signal.

And increase the ampitude while watching live data?

When is the code triggered ?

Can you scope the signal as its triggered ?

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