Speedometer gear (and odometer) is not working properly

PEDRODUARTE

MEMBER
1993 HONDA DEL SOL
1.6L
4 CYL
2WD
MANUAL
200,000 MILES

Hello!

My car (MT) is showing the wrong speed by a lot. Not sure when it started but it has been more than a year and I think that it is becoming more and more off.

At the moment it is 30% off, showing 60 km/h when it should be around 80.

I replaced the VSS twice. First by a second hand. And today by a new one, bought at Honda dealership.

The error is still there. Do you have any idea's as to what could be the cause? Hope it is not a problem in the drive-train.

3 Replies

STEVE W.

MECHANIC
12,961 POSTS

Being it is an electronic speedometer the easy way to determine if it is sensor or a bad servo in the cluster would be to put a scan tool on the car that can read live data. Then compare the readings from the sensor to the speedometer. You may also want to compare the odometer readings to actual driving distance. It is driven by the same sensor but through a different circuit in the speedometer head. If you drive 10 km and it reads 10 km the signal to the speedometer/odometer head is okay and it is a faulty speedometer head.

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Wednesday, August 22nd, 2018 AT 7:43 AM

PEDRODUARTE

MEMBER
2 POSTS

Hello,

I connected a data-logger to the car and indeed the sensor is outputting correct readings from the drive-train. I also realized the tachometer and odometer are off, so I think it may be a problem of the entire cluster.
Thinking about it, I did change all the bulbs in the cluster to blueish LED's, maybe that had something to do with the overall malfunction? Perhaps an excessive drainage of the power supplied to the cluster that affects the operations of the remaining cluster components? However, LED's drain less than older bulbs. Ah! Got to find a replacement cluster and test it out. :)

Thank you guys.

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Monday, August 27th, 2018 AT 5:14 AM

STEVE W.

MECHANIC
12,961 POSTS

I doubt the LED's are the issue. However, it is possible that the removal and replacement of the cluster did disturb the connections, especially a ground. If the ground connection was corroded or higher resistance it could cause odd behavior due to the voltage being incorrect to the cluster.

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Tuesday, August 28th, 2018 AT 6:28 AM