Will this fix my 95 Accord V6 tachometer?

Question

I purchased a 95 Accord V6 that runs great, but the tachometer is always at 0. The check engine light is on with a P0725 error code. I did some google research and read this article that suggests I replace the ignition coil:

http://findarticles.com/p/articles/mi_qa3828/is_200204/ai_n9079886

Only thing is that the article mentions an "erratic" tachometer, not a broken tachometer. I also stumbled upon a forum thread where people were discussing success at fixing their "erratic" tachometers by replacing the coil. I really don't want to shell out $80 for a new coil only to find that my tach is still sitting on 0. Is there anything I can check on the car before I purchase a new coil?

Answer 1

While your research says 'fluctuating' the reality is that the only way to cure the check engine light code DTC p0725 is to replace the ignition coil. that code is for a torque converter clutch that isn't locking up and that means your fuel economy is probably lower than it should be, particularly if you do highway driving.

According to Honda, for the A/T DTC P0725 (lockup clutch does not engage), the cause could be a faulty resistor in the ignition coil. The transmission control module (TCM) provides electrical pulses through this resistor to drive the tachometer. if the resistor is open circuited, the tachometer will not work, period.

A faulty resistor doesn't affect the coil's ignition functions, you' ll still need to replace the ignition coil to fix A/T DTC P0725 as the coil resistor isn' t available separately.

I expect that you'll have to get the part from Honda as I couldn't guarantee that the aftermarket coils have the same resistor in them (the resistance may be different than the factory coil and that could cause the same problem). Most electrical parts are not returnable, so if you were to buy one in a parts store and it not fix the problem you'd be out the price of the aftermarket coil and still have to buy the honda part.

hope that helps

Answer 2

If that's where the tach gets its signal that's probably your solution. Give it a try, probably won't cost more then $100.