Hi Team,

I am recently facing this problem in my car. the speedometer needle does not go below 40 kph, when i start the car it shoes 40 kph. wht must have gone bad or damaged ?

 

When the car is off does it drop to 0, or stay at 40?

 

it stays of 40

 

Hmm well if you haven't already done so, try disconnecting the negative battery terminal and leave it disconnected for a few minutes. Maybe that'll reset something and it'll go back to zero

 

i havent tried disconnecting the negative terminal from the battery.
but when i sit in the car, i can see the needle on 40 before even i had press the ignition.

 

i havent press the ignition but the speedometer is at 40 kph, wht can any1 suggest for this problem?

 

What happens when you start driving? When you're going around 20kph does it show 60? And when you're going around 60kph is the needle at 60, 100 or 40?

Disconnecting the battery will reset some of the computer systems, which may resolve the issue. I'd try that first since it's the least invasive thing to do!

 

I disconnected the negative battery but still it's on 40 while at Parked

yeah while driving at 60 it's shows 100

 

pull out the speedo cluster and manual free it up maybe theres a sticking point

 

Do you have access to techstream app? There's a way there to test the speedo and discard a malfunction.

I will also check the speed sensor, i believe the 3gs have 2, one on the right rear and front right. Might need cleaning or replacement.

I am around 80% sure its a faulty speed sensor.

 

Sounds like the calibration is off. Both ibidu and guzzy have good suggestions, though I would start by hooking up to a computer with Techstream since it's the less invasive of the two!

 

To me it looks like the mechanism for the needle itself has jumped. Since the needle still increases with speed that means the cluster is receiving inputs from the vss(vehicle speed sensor). My advice is to find a technician that knows how to correctly check the electrical circuit using voltage drops and a lab scope. That should tell you if you're getting a bad signal or a faulty cluster. I'm guessing cluster.

 

I,m not sure how involved it would be to remove speedo and rotate needle to zero from behind and see if it works.