I recently bought a 1992 Honda Accord with about 85,000 miles. The vehicle does not upshift or downshift, I have to manually shift it. It does not go into overdrive. The D4 bulb also does not illuminate, I have replaced it. The gearshift can also be moved without the key or brake depressed. Anyone have an idea of what could be causing it? My thought was, some of this has something to do with the fact that the gearshifter can be freely moved without the key or the brake pedal being depressed. Is it possible that the shift position Switch is defective, and therefore is causing a grounding issue for the d4 bulb? We are unable to pull codes if there was any because the d4 bulb does not illuminate.

 

Do any of the gear position lights work on the gauge?

Do your brake lights turn on/off when you push the brake pedal?

Some of the 90-93 accords had an LED on the ECU and TCU where you could count flashes. I can't remember if they stopped having them on the 91 or 92. Just pull the passenger carpet back to see if there is a plastic window with a LED.

To figure out the problem, you will need to be able to use a volt meter to test for 12V and for open/closed circuits. Do you know how to do this?

 

Thank you so much for your reply. The vehicle is currently a transmission shop in Auburn Massachusetts, Interstate D Transmission. They will be performing all the test, and they have been very open-minded to hearing any feedback that we may find online. From what I recollect, the brake lights did light up, and the other gear selectors still illuminated. I can have them check on the LED window on the TCM, but they said they are unable to pull any codes at this time because the D4 bulb does not illuminate.