My 1992 LS 1.8L Auto with AC upshifts and the engine runs smooth but the AT will not kick down a gear or two under a pedal-pressed attempt to accelerate. It throws codes 3 and 7 for the MAP and TPS. Replacing the MAP made no difference. I checked the TPS and determined it is NOT getting the required 5V feed voltage. Is there anything that might cause this failure to downshift other than a bad ECU? Has anyone had a similar problem? I have frequently changed my ATF and it is clean and the car downshifts as it slows down, just not when the pedal is depressed under a hard acceleration attempt. I’d hate to replace the ECU (hard to find and $$$) and find another issue. Any help appreciated!
This a super shot in the dark here, but several years ago, I had a funky situation like this. I can’t remember what codes the ECU stated, but what actually made things go wrong was a corroded positive battery cable and poor battery ground (under the battery). (I had some other things going weird like wipers / chimes too). Is ANYTHING else wrong? Regardless, those are easy things to check at least. Frankly, the issues I’m having now are just bad wiring all over the place 
Did you do any wiring tracing or discover any kinked wires from the ECU harness?
I will remove the battery and check the grounding wire. Thanks. I don’t want to pull the trigger on an ECU ($$$ with no returns) until I’ve tried anything and everything else suggested.
Checked - battery terminals and ground cable attachment A-OK and not the problem (heavy sigh). I am sending the ECU out for “repair” - $205 with shipping to repair, $99 inspection fee + $26 shipping if ECU is okay as is. I’ll report back.
What company did you use? I bought a new one from fs1inc.com .
I’m also wondering if it’s the separate transmission computer :-/
“if it’s the separate transmission computer”
Nononono . . . 
You are freaking me out!
With a quick inspection, there does not appear to be a TCM behind the driver’s side kick panel, just a fuse box. (“Belt warning control” box on the passenger side.) Isn’t the ECU an integrated unit that also controls the AT (1992)? I ordered the ECU repair service from Module Experts, a fraction of the cost of a new/rebuilt unit.
I have never heard of the transmission computer going bad. Just something else to look at given the age 
I’m just going off memory here. Let me take a look at the Helms when I get home. I could be mistaken.
I am pretty sure there is a gold box up in the fuse box area that would be your TCM. Hopefully the ECU sorts out your issue. Stay patient and rule that out first! When the trans is acting right, the auto is really a lot of fun to buzz around with in S3/S4.
It would appear the sole source of power to the TPS is via the ECM so if you’re having a power supply issue that is likely to be your source.
Just checked (learning as I go) and there is no 5V power to the MAP either.
Regarding your 5V statement: This is also something I’m dealing with the EGR valve system. I have not determined how to fix that yet but wondering out loud here if a similar component (but in separate locations) could be doing this.
When does your ECU arrive?
The block diagram that I found that is ?likely? for my ECU does not show a pin specifically for the EGR. But it could be the #19 pin labelled “VCC1” or #20 pin labelled “VCC2” on the 22 pin block which are apparently both for “5V+ Signal for Sensors”. I’m thinking that is probably the bad part of my ECU, unless it is both pin 11 TPS and pin 17 MAP, both on the 22 pin block. I did not test ECU outputs and have just sent it out today, I don’t expect it back for at least a week.
Edit: my ECU is 37820-PR4-A61
I think this diagram is correct for this ECU.
New at this . . .
Regarding replacing capacitors in Honda ECU’s, do “bad” capacitors always show leakage? Can capacitors that appear A-OK be bad? I just picked up a used ECU (eBay) which was sold with supposedly bad capacitors and which would neither prime the fuel pump nor start the engine when plugged in. Visual inspection of the board shows only the tiniest bit of green on the board at the wire of only one capacitor (C18) which does not look like enough to cause problems. I am awaiting a capacitor kit from Amazon but wondering if this is the problem, and might I have to replace more than one “healthy” looking capacitor?
Man it’s been years, but I’m pretty sure you can check the capacitance on the board itself with a multimeter even while it’s still on the board. Someone correct me if I’m wrong.
Well, now I’ve swapped out 7 capacitors on this eBay board using the 8 capacitor RemTune replacement kit (there does not appear to be a C201 on this board). The engine turns over but no start with this ECU, and still no sound of the fuel pump priming.
What else typically goes bad in these ECU’s?
I still have the original ECU out for repair, no word yet.
My 93 LS (manual transmission) had a no fuel pump prime and I was even checking the connections at the fuel pump under the seat. The ONLY way it was fixed with replacing the ECU. The OEM ECU looked in pristine condition. I never figured out what the problem was, but I was done checking after spending many many hours troubleshooting. I even removed the car alarm thinking that was the problem. Electrical problems… Ugh.
Update: Disappointed and a bit pissed. My ECU was returned from “ModuleExperts” with a baggie of 7 removed capacitors - which all looked in great condition. The ECU is exactly the same as before. I checked output right at the ECU connector and NO 5V+ supply voltage at either pin 19 or 20 - MAP and TPS. Then (hindsight) checked the reviews of this outfit to find out they are terrible, pretty much as bad as I’ve ever seen. Called them up and they claim 5V+ was there when “repaired”. NOT! Their warranty info (shown on return info only) states you must have documentation that a qualified service performed the ECU installation. Yeah - have my car towed to a dealer to plug in three connectors! DO NOT DEAL WITH THESE PEOPLE! I have now spent about $500 and am no closer to fixing the ECU issue.
Holy crap that’s terrible!
Maybe keep a look out on ebay ?! More $ for uncertaintly though — this is super frustrating!
Sent it back on “Warranty Return”. If these yahoos don’t fix it this time I think I’ll just have to fork out for an expensive ($600-$700) replacement. My beautiful DA is not safe to drive with no gear “kick down” acceleration.
What about those systems that eliminate the ECU altogether and you start from scratch? I think that starts around $1k USD.