Intermittent speedometer
Thread Starter
Race Director
Joined: Sep 2001
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From: Between a rock and a hard place, S.E. PA
Intermittent speedometer
2007 A6 LS3, ~20k miles
My speedometer and HUD have begun to intermittently read 0mph. The odometer also stops registering while those are out. The auto trans still shifts perfectly.
I plugged in my HPtuner software and the MPH showed up on the scan but not on the dash or HUD. Then, one day they mysteriously started working on my way home from work. The next morning, 0 again. On my way home the same day, working again.
I'm thinking it might be temp related. It sits in the cool garage over night but in the sun at work during the day. Any thoughts on the best place to begin looking for the cause? Thanks.
My speedometer and HUD have begun to intermittently read 0mph. The odometer also stops registering while those are out. The auto trans still shifts perfectly.
I plugged in my HPtuner software and the MPH showed up on the scan but not on the dash or HUD. Then, one day they mysteriously started working on my way home from work. The next morning, 0 again. On my way home the same day, working again.
I'm thinking it might be temp related. It sits in the cool garage over night but in the sun at work during the day. Any thoughts on the best place to begin looking for the cause? Thanks.
Thread Starter
Race Director
Joined: Sep 2001
Posts: 11,907
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From: Between a rock and a hard place, S.E. PA
Thread Starter
Race Director
Joined: Sep 2001
Posts: 11,907
Likes: 1
From: Between a rock and a hard place, S.E. PA
Ya know, some days it just doesn't pay to get out of bed. I'm lucky they still allow me behind the wheel. 
At any rate, it goes to the dealer tonight. The sad part is, it's been working since the day I made the appointment with the exception of one start cycle. I'm preparing myself for the "could not duplicate problem" stamp.
At any rate, it goes to the dealer tonight. The sad part is, it's been working since the day I made the appointment with the exception of one start cycle. I'm preparing myself for the "could not duplicate problem" stamp.
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Joined: Jan 2011
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From: Des Moines, Iowa
Mine had this issue today on a 3rd gear run. Near redline all of a sudden the speedo went to zero for a few seconds. Coasted down and went to 5th gear and it came back.
Post up if/when you find the root cause, I hope mine doesn't start doing this more often. In the past the speedo has twitched a bit, going from 65 down to 55 and back up for a split second, but has never gone to zero for a few seconds like tonight. Has me worried.
I have a manual trans if that matters.
Post up if/when you find the root cause, I hope mine doesn't start doing this more often. In the past the speedo has twitched a bit, going from 65 down to 55 and back up for a split second, but has never gone to zero for a few seconds like tonight. Has me worried.
I have a manual trans if that matters.
Thread Starter
Race Director
Joined: Sep 2001
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From: Between a rock and a hard place, S.E. PA
I'll keep everyone posted in case this gets to be a common issue over time.
While driving to the dealer last night the speedo dropped to 0 while in motion. All the other times were from a start. Before I could get my cell cam out to record it (evidence to persuade the dealer to keep looking), it went back to normal. Should get a call today.
While driving to the dealer last night the speedo dropped to 0 while in motion. All the other times were from a start. Before I could get my cell cam out to record it (evidence to persuade the dealer to keep looking), it went back to normal. Should get a call today.
Thread Starter
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From: Between a rock and a hard place, S.E. PA
Well, I learned a lesson today. Apparently, under the GMPP extended warranty, if the dealer can't locate the problem, the customer gets billed for the time spent. Had I known this beforehand, I would have waited until I had a complete failure. They knew it was intermittent when I made the appointment and that I have GMPP but didn't think to warn me about the policy.
If that wasn't a slap in the face, they also billed me for an oil change I didn't request! I don't know what came over me because I agreed to pay for the oil but not the labor or filter. Turns out they charge over $10/Qt and only $12.95 labor and $5.xx filter. So it was only a $19.xx refund for a job I do myself. I've got about 20 Qts of oil and 5 filters sitting on my shelf because I buy them whenever I see a sale.
So, I still have no idea what the problem is and have a brand new reminder of why GM shouldn't have been bailed out. Sorry for the rant but that's how my day ended.
If that wasn't a slap in the face, they also billed me for an oil change I didn't request! I don't know what came over me because I agreed to pay for the oil but not the labor or filter. Turns out they charge over $10/Qt and only $12.95 labor and $5.xx filter. So it was only a $19.xx refund for a job I do myself. I've got about 20 Qts of oil and 5 filters sitting on my shelf because I buy them whenever I see a sale.
So, I still have no idea what the problem is and have a brand new reminder of why GM shouldn't have been bailed out. Sorry for the rant but that's how my day ended.
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From: Between a rock and a hard place, S.E. PA
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Joined: Jul 2002
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From: St. Louis, MO
St. Jude Donor '08
Do you have aftermarket gears in the car? Even if you don't, unhook and re-hook the sensor on the top of the diff which is the reflector sensor that tells the car how fast it's traveling.
Here is a pic so you can see what you are looking for.
I have a feeling it's not that though since you say it shifts fine and it reads accurately with HP Tuners.
Do the other gauges work when it happens or do they all go to 0?
If they all go to 0, and you have a window valet, disconnect it when it happens and see if the gauges come back on. I had a window valet go bad and it did that.
Here is a pic so you can see what you are looking for.
I have a feeling it's not that though since you say it shifts fine and it reads accurately with HP Tuners.
Do the other gauges work when it happens or do they all go to 0?
If they all go to 0, and you have a window valet, disconnect it when it happens and see if the gauges come back on. I had a window valet go bad and it did that.
Thread Starter
Race Director
Joined: Sep 2001
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From: Between a rock and a hard place, S.E. PA
Thanks for the pic. I pretty much ruled that connector and cable out when I was able to get a reading with HPtuners while the speedo was at 0. No other gauges appear to be effected and no valet. Doesn't seem to be effected by bumps.