malfunctioning speedometer

[asiancivicmaniac]

Hi everybody, my dad has a 2000 Nissan Quest that has had a glitchy speedometer for the last couple of years. I post once on here about a year back and really didn't get anywhere, but I made a couple of new observations so hopefully somebody can help me out here. The speedometer would work and sometimes after driving a few miles it would twitch a few times and drop to 0. What I noticed when we drove our sister to college two days ago is that it would be fine above 50 mph. When we slowed down on the highway due to traffic, the needle immediately dropped down. When we got back up to speed it would work again, weird. We took it to the Nissan dealer last year but they said they couldn't replicate the problem and left it at that. It's not that much of a problem, but more of an annoyance. If it's something that is easily fixed then I might get my dad to look into it, but if it's going to cost big bucks then it's going to get left alone. Any input is appreciated.

edit: I also have a suspicion that it may be related to the transmission flush that my dad got about two years ago since the problem seemed to have appeared around then, but I am not sure.

 

[dwendt44]

Most, if not all, newer speedometers are electronic.
Check the pick up on the top of the transmission.
Remove the drive and make sure the little plastic gear isn't worn down.
The problem could easily be electrical, so check that the connection at the transmission and behind the gauge cluster are clean and tight.
Look for cracked insulation at the back of each connector.
Any problem with any of the other gauges?
That might indicate a poor/bad ground for instruments.

 

[alanu]

If only the speedo gets effected I'd suspect the speedo itself or the sending unit on the transmission.

Call the parts dept of Nissan and ask if its a commonly sold item.

 

[Anduril]

My wife had a glitchy speedometer at one point, it'd randomly spazz out all over the place from 0-100 for a few seconds while she was maintaining a constant speed, then it would go back and do what it normally does for a few days, then it would spazz out for a few seconds again, eventually it quit spazzing without either of us doing anything to it and now it works fine again.

 

[wantin150]

Ran into an issue like this with my 1993 Corolla. The odometer kept working but the speedo wouldn't. It needed a new head unit at about $305. To retain resale, you may want to have the dealer install so you can verify the mileage. I did it myself and when I went to trade the car, they only offered me $500 when blue book as $1200-1800. I said no thanks, made a phone call and sold it for $1200. I had even kept the old head unit as "proof" but they would have nothing to do with that.

 

[punisher]

If you have cruise control, see if the cruise control bucks/surges/cuts off when the speedo acts up. If it does, you have a speed sensor problem. If cruise control is uneffected you have a flakey speedo head/wiring.

EDIT: This assumes an electric speedo head, no cable.

 

[mechtech2]

Actually you can have it on cruise control and it can go in/out of overdrive, depending on road and load conditions.
Is there is a difference when manually going from OD to DR at cruising speeds?

 

[asiancivicmaniac]

I don't drive the car much. And the cruise control is seldom used even on the highway so I don't know if it's affected by the speedo. Thanks for the answers, if it cost several hundred dollars to fix then most likely it won't be fixed until the speedo fully goes out.

 

[GMGuy]

Does your odometer work when you are driving slow? If it is, its probably just the speedo itself. If it where mine, I'd see about swapping the speedo with a wrecking yard unit (not the whole instrument cluster, just the speedo)

Alex.

 

[GMGuy]

Just becuase this will come into question, if you want to do it by the letter of the law;
Florida gov. site

(2)(a) This section does not prevent the service, repair, or replacement of an odometer if the mileage indicated thereon remains the same as before the service, repair, or replacement. If the odometer is incapable of registering the same mileage as before such service, repair, or replacement, the odometer must be adjusted to read zero and a notice in writing must be attached to the door frame of the vehicle by the owner or his or her agent specifying the mileage prior to repair or replacement of the odometer and the date on which it was repaired or replaced.

Couple of notes:
If the odo reads higher, thats usually not a problem. If you plan on selling the car, that might be something your concerned about.
I also wouldn't be concerned with an odo that is lower, but reasonably close ie: reads higher than your last dmv reported mileage was.
Your car may not even have an issue with this if the nissan has the odometer as a separate component from the speedo, or it is signaled from the ecu and any odo will read the same for that given ecu.

Alex.

 

[BrianWC]

FYI, when my ABS control unit was on it's way out, it exhibited the same behavior. Granted, I would also get ABS and traction control idiot lights come on, but....

 

[aaxb970]

The three thing that could be wrong with your speedo are :

If Speedo cable.

- Speedo head unit gears worn.

- Transmission speed gear worn.

If Electronic.

- Dirty speed pick up sensor in transmission.