On my '93 Accord the check engine light is on solid, D4 is flashing. After plugging in the service connector, I believe I’m getting four distinct codes. 1 flash... pause... 2 flashes... pause... 7 flashes... pause... 8 flashes... then it repeats. All flashes are same duration, not a combination of long and short.

The manual indicates these codes refer to the lock-up control and shift solenoid. I find it peculiar that four codes would show up simultaneously. My son who uses this as his transportation says when cold the transmission shift seems delayed, but is fine once warmed up??? The codes showed up when it was cold as well. I plan to check each the resistance of each solenoid and see if it’s in spec.

I wanted to see if anyone had any ideas or thoughts on this.

Many thanks.

 

Are those all flashed by the D4 lamp? Is the CEL doing any flashing also?

 

CEL is on solid the whole time, all flashes are on the D4 lamp.

 

I'll read these as 1, 2, 7, and 8 from the tcu.

First know that the tcu's in this gen are kind of known for going bad......

Check and clean the solenoids. Be sure the connectors to said solenoids are clean and tight, I've seen a few where "gunk" was built up causing bad connections and or causing the tcu to blow because of high resistance.

Be sure the ground is clean and tight as well....battery end, body connection and then the trans connection....yes these are important IMO.

 

Thanks for the response, good things to check.

I replaced a failed TCU this summer, which was causing shifting problems. The failed TCU had overheated components on the board. A used TCU from the local salvage yard fixed the problem. No issues until now.

I reset the TCU by removing the radio/backup fuse and took it for a test drive this morning. Only went a few miles, but the code did not return and transmission shifts are normal. So it appears to be an intermittent problem… ugh. I’ll monitor and see if the codes return.

 

I would double check the connector(s) to the solenoids. Seen a few of these where there is a bad connection there that will cause high resistance.....this can set interm codes and also at some point cause the tcu to fry again. Some have cleaned them with elect contact cleaner, others spliced in a new two wire water proof connector to resolve the issue.........see what happens.