[sdrobot]

I own a 1999 Honda Accord EX 4cyl. Recently I was driving on a very cold day (-10 f) and had the tachometer and speedometer die, that is drop to zero. The car continued to run fine and both the tachometer and speedometer would occasionally come to life. I took it to a dealer who diagnosed the problem as the main circuit board. They did not have one in stock and being I was out of town I elected to drive it home with no problems the following day. It continued to run fine for about 3 weeks and then the other night as I was driving home it acted up again. This time the speedometer and tachometer thing happened but also seemed to slip out of gear. That is as I stepped on the gas the engine reved but the car didn't go. I pulled over and after waiting a moment tried it again and got it to go but only to about 5 mph when it would slip out of gear again. I was able to get home. The lights in the interior all appeared very dim as well.

Does this sound like a main circuit board issue or could there be other issues going on as well?

[TxGreaseMonkey]

Speedometer, odometer, and trip meter problems are related. If the odometer and trip meter work, but the speedometer does not, either the speedometer or the printed circuit board (PCB) are bad. If the speedometer, odometer, and trip meter do not work, focus on a blown underdash fuse, Variable Speed Sensor (VSS), or main ECM ground. However, tachometer problems are a separate issue. Therefore, several issues may be involved. Here's what I would do:

. Check all underdash and underhood fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-t...tml#post252145

. Clean the main ECM ground, located on the thermostat housing, since the VSS grounds through the ECM.

. Remove the dashboard PCB and clean connections going to the speedometer and tachometer.

. Replace the Ignition Control Module (ICM) and coil, if the problem persists:

https://www.askmehelpdesk.com/cars-t...tml#post265896

The ICM may be failing, which is very common in Hondas of this generation. Since the BLU wire from the ICM drives the tachometer, it makes sense (200 pulses per minute from the ICM for every 100 rpm). Don't underestimate the effect of a failing ICM on general performance--it can be profound. I recommend replacing ICMs and coils every 120,000 miles or 10 years, whichever comes first.

Here's what the ICM looks like and costs:

http://shop.advanceautoparts.com/pro...pe=194&PTSet=A

Transmission slip may be related to a failing ICM and poor engine performance; otherwise, it may indicate the VSS needs replacing or the transmission needs rebuilding, due to the fluid not being changed frequently enough. If the problems persist, replace the printed circuit board in the dash.