Tach and Speedometer not working

[Buzclick]

Having lots of fun with my 2006 Subie forester. Recently been getting misfires when it rains - found out the coil is cracked in 2 places - to add insult to injury, there is oil starting to leak. My '98 Forester blew the head gasket long before reaching our Subies current 111,500 and when we were 300 miles away from home, my weird luck, we have to take the same trip again soon. Not a problem, its obvious what needs to be fixed. However, my Speedometer has been intermittently doing pendulum swings then getting stuck at a certain speed (usually 34 or 72..), tachometer started joining last winter. Usually this goes away after stopping and restarting. After a much needed tune-up a month ago (changing out all the plugs & wires), the problem seemed to go away. Today, first warm day, it came back with a vengeance. Tach was stuck at zero, I turned off the car and the speedometer still read just over 70. Funny thing, I was bringing it to my mechanic when this happened because of the misfiring, so he had the chance to see it. On the way home had to use GPS to gauge speed, both tach and speedometer read zero. Any idea how to approach this?
There was one instance of the cruise control and speedometer not working and the check engine light coming on - but this only happened when the spark plugs were also misfiring.

Edited April 11, 2017 by Buzclick

[gbhrps]

Buzclick,

 

Sounds electrical, and if it were my car I'd first pull the instrument cluster (easy to do), disconnect the wiring harnesses to its back, and then reconnect them. If that didn't do the trick, I'd be tracking down the engine and body ground wires and ensure that they were properly grounded and not corroded or broken.

 

If neither solves the issue, its a fix for the experts. Good Luck!

[wtdash]

Hi,

If the CEL is on or has been on, pull/get the codes and report back. There 'should' be codes for a VSS or 2, if it's related to the sensors. 

 

But it could be in the cluster like the '99 Legacy models - as noted above.

 

2006 was about the time Subaru changed from the gear drive speedo sensor in the Trans by the diff oil dipstick, to the newer version - of which I'm not familiar but think it's related to the ABS??? Maybe?

 

The misfires could be related to the code as well.

 

Here's a link w/some info.

 

GL,

TD

Edited April 14, 2017 by wtdash