Skip the auto shop - Our mechanics make house calls

Q: Speedometer not working.

asked by on

The transmission was overfilled causing the fluid to not cycle properly. The fluid then overheated on a trip, burned some, and the speedometer stopped working. The battery was old and needed to be replaced. To get the car started after the transmission fluid overheated I had to jump it. The power steering light came on shortly after. I took it to a dealership. They replaced the battery, drained and refilled the transmission, and replaced the vehicle speed sensor on the transmission. When I took it to an independent mechanic he claimed I needed to replace the speed sensor again. I bought a speed sensor and replaced it myself a second time as it is a relatively easy process, but the speedometer still didn't work. When I replaced the speed sensor, I noticed the shaft that transmits rotation from the transmission to the sensor didn't have a gear head on it the way some of the pictures have shown it, it just had a roughened top. Is that a problem? The car doesn't have ABS.

My car has 100000 miles.
My car has an automatic transmission.

The speed sensor itself does not have a gear permanently attached to it. The driven gear as it is known, should be already installed in the transmission. There is most likely a single slot that engages with the top of the driven gear. You will need to turn the sensor a little to get it to mesh with the slot. If you are doubting the gear is not turning, you could put both front wheels in the air. Warning, do this at your own risk and take every precaution to be safe. Once the wheels are off the ground and the car is supported by jack stands with the rear wheels blocked with chocks, start your car, put it in low gear and look inside the transmission to see if the gear is spinning. Of course, you will want the speed sensor removed from the transmission while doing this. If it is moving, you can be reasonably assured the inner workings of the transmission are good.

If this checks out good, the next step is to check to see if the instrument cluster is receiving a signal from the sensor. The ECU (engine control unit), instrument cluster, aka (combination meter assembly) and a ground are involved with this system. The scanner will give a qualified technician a clue about where the diagnostic path should lead next.

If you would like to have a certified mechanic take a look at this for you, a certified technician from YourMechanic can come to your car’s location to inspect the speedometer problem.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The EPS indicator came on when I started my 2007 Honda Fit.

Yes, you should. There may be a problem with something as simple as a position sensor or there can be an intermittent fault from the electronic motor that give you the power steering assist. The warning like came on and...

Q: Car won't move forward

Usually, if the car will not go forward it mean the transmission is shot. This depends on if it is an automatic or manual transmission. I'm just assuming that it is an automatic and there is something wrong with the...

Q: How do I put on a seat belt correctly?

Wearing a seat belt can save lives, but only if it’s put on correctly. Otherwise, it can be dangerous in an accident. Pull the shoulder belt forward so that it extends over the shoulder but not touching the neck....

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...