D4 flashing & car won't start.
 

When I make short drives and shut down the car, often I come back to find the D4 flashing and the car will not start. I've replaced the transmission computer and the shift solenoid, but still have the same problem. Sometimes it will start, but only 2nd and 4th gear are available. Usually, I have to wait about 30+ minutes for whatever to cool down before I can get the car to start. Any ideas?

Main relay??? I'm not sure but this may be cause!!!

Any codes come up??? Check for codes

Not main relay. Your transmission computer detected a problem and has a code store that will help you troubleshoot.

Short a two pin blue connector on the pass side of the car using a thin paperclip. It is near the kick panel. Turn the key to the II position then count the D4 light flashing. A long blink = 10, short blink = 1.

L L L S S S = 43.

Post the code on here.

I had the same kind of problem. Replaced the trans computer too but would still get the "s" (same as D4) light on, missing gears and no start sometimes. Took the PGM-FI main relay out and resoldered everything (make sure to removed the old solder, don't just reflow it) and both problems were fixed. Where are you located? I'll help you if you are near me. Take a look here for instructions. http://techauto.awardspace.com/

Don

Wow. I didn't realize that a main relay fault could set a TCU code.

Do you remember what code was stored in the TCU caused by a problem with the main relay?

The main relay powers a lot of stuff. The power circuit for the fuel pump is the most common failure of the main relay, but it also switches power to most sensors & solenoids. Only guessing, but say that power was interrupted, you'd get CELs for any of that stuff like O2 sensor heater, EVAP purge solenoid, etc...

I can't remember but I think the TCU gave a 7 or 8 which was the shift solenoid. And the CEL gave a code related to the fuel injection, can't remember that code either. But the fix for the relay corrected everything.

I'm in Carrollton, GA, about an hour WSW of Atlanta. Ok, guys, I'm not that technically proficient. PAhonda, I'm not sure where to find this 2 pin blue connector. Is there a simple fix? I do not know how to solder or do anything electrical. Thanks for the ideas, though. You guys really know the Accord!

Here are instructions for the 94/95 accord. http://www.dhost.info/accordinfo/howto/cel.html

The difference is that your 91 accord has the two pin connector in a different location. It is still under the passenger dash, but it is near the kick panel (plastic piece protecting wiring from passenger's outside foot).

You can short it using a bent paperclip. Turn the key to the II position. Count the flashes from the D4 light to get the transmission code. Post that code on here, and we can help.

The main relay powers the fuel pump. When you turn the key initially to the II position, you should hear several clicks. During the pause in the clicks, you should hear the fuel pump turn on for ~2 seconds. Listen carefully, it is a faint buzzing/whirling sound coming from the back seat. If you do not hear this sound, then the main relay should be repaired or replaced. Definitely diagnose first.

The main relay is not technically hard to replace, but you have to know the location. This site has an excellent set of instructions. http://techauto.te.funpic.org/mainrelaydefine.php

JetJock,

I'm in Austell so we're pretty close together. My sister-in-law lives in Carrollton. I'd be glad to come out to see if I could help. I can definitely help you pull the codes and resolder the relay. Let me know if you want some help. I'll PM you my cell number.

Don