buhtwipe

Hi all,

I'm new to the forum and decided to join since ive seen so much great information on here from googling about my problem. Here is a summary of what ive run into and have done so far. I'm a bit lost now as to what to do next.

[Vehicle]
2004 Honda Accord EX Coupe 2D Automatic.

[Symptom/Issue]
Turned car on and "D" blinking with check engine light on. Car would not shift or attempt to shift into 2nd gear, it would simply rev higher in 1st gear.

[Investigative work]
Googled around for things to look into so i dont fully trust the fine details of the tests I've done and am hoping people here know better.

ODB code is "P0966". This apparently points to a low voltage issue at pressure solenoid "B", yes? So several days have gone by and I've done the following things and right now I'm thinking ECU but have never had to change one so i dont trust that idea yet so im looking for advice.

I basically followed the tests at this site (pay attention to #4)

http://members.iwebplanet.net/jcasti...AT00.HTML#i090


[step: Measure A/T clutch pressure control solenoid valve B resistance at the solenoid connector]

1. Ohm's were about 8 testing the solenoid "B" terminals on the solenoid itself. I believe this means it's good.

[step: Check for continuity between the No. 2 terminal of the A/T clutch pressure control solenoid valve B connector and body ground.]

2. Yes there is continuity.

3. All three engine grounds are strong, tight, and clean.

[step: Measure the voltage between terminals of the A/T clutch pressure control solenoid valve B connector.]

4. This came in at about 8V. The site above said to expect 11V. So i began to think of a wire or ecu problem here. I googled around more and many solenoids like this work at about 7V+ and disengage when volts drop below 1. So now I am confused and possible question the 11V expectation.

5. I tested running 12V from battery through the brown/white wire that runs pressure solenoid "B" from the solenoid connector and all the way up to the final ECU connect and 12V went through with no problems so i think the wiring is fine, yes?

? What should I be seeing here, is 8V ok?

[step: if voltage is good from the test above then... Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.]

6. I replaced the dual linear pressure solenoid A and B anyway. Same issue, yes because it is not the solenoid and the ohm test and direct 12v click test proved that.


... my questions ...
1. So here i am.... Is my ECU really bad? I opened it and smelled and looked for burnt resistors or anything bad and it looks just fine.. Honda wants to charge my left nut for a new one.

2. My ECU is 37820-RAA-A56. I called Honda and the one they sell now is either a marketing ploy with a simple revved number or actual updated better ECU programming but their ECU replacement is 37820-RAA-315 for my car per their VIN lookup. If I bought, say, a used "A56" will it not work in my car unless I pull keys or whatever codes are on mine and inject them into the new one I bought (reprogram the new/used one)? Or will it swap right in and there is no immobilizer or whatever?

3. Should I do other tests? I have done every test I can think of and find and all wiring looks good.

4. Is 8V enough with ignition key in on position and testing voltage running to solenoid "B" on the brown/white wire or is that web site above correct and it should be 11V and my ECU truly is shot?

Appreciate all the help I can get! Love my car and want it to just work again.

buhtwipe

Forgot to mention another thing, could be coincidence... i noticed the car starts a litttle rougher (several cranks instead of 1-2 cranks) since this began and it idles rougher too.

before the code went on, it purred and started right up.

buhtwipe

Another question. Sorry as you can see im googling frantic... found out about a "J2534" standard that allows for reprogramming.

if i bought a J2534 cable for honda, and i have already downloaded honda's free pcm programming software for use with a J2534 connection... can i get my immobilizer or keyed codes off of my old computer before putting in a new computer (ECU) if that is the route i must go down?

programming guide: http://aftermarket.ahmhds.com/PCM_INSTR.doc

programming s/w from honda: http://techinfo.honda.com/rjanisis/p...lizationSW.htm

the cable for honda cars:
http://www.dinodirect.com/mongoose-f...FWJlMgodeAcAqw

buhtwipe

Any ideas anyone? LOL

Can I only get the following two ECU's to work with my car? If so, how do i get the immobilizer and new ecu to work right?

37820-RAA-A56
37820-RAA-315

What else might be wrong from above descriptions?

buhtwipe

Please help

If i can get 12v through the wire from battery via solenoid connector b and all the way to the other side near ecu then my wire seems fine right? If in addition to that, the ecu only sends 8v with the ignition key in on position.. and the solenoid resistance is in correct range, doesnt that imply the ecu to be the issue?

only other weird thing is that the car starts harder (maybe 6-7 cranks) instead of 2 like it used to. im not sure i hear the gas pump get primed even now. I'll have to double check that.

plz help lol, this is my best care ive taken care of it, i want to fix it.

Accordman1

You are doing all the right things to diagnose the problem. I believe that it is the ECU problem not producing the voltage necessary to trigger the AT solenoid. Most of the electrical relay or solenoid in a car require 12V input, 8V seems too low to get it worked. I think you gotten a lot further than an average Joe to get to your conclusion. You may also want to check the ATF fluid level and color to determine if you need to top it off or replace it. If the ATF level is good, then, you have basically two choices: buy a used ECU and a factory service manual or order a new ECU and a factory manual. Most people don't have one or need one due to cost of the service manual but you want one to get it done right without doing damage to you car. Follow the factory instruction to reprogram your used or new ECU and let us know if that fixes your problem. I wouldn't want to rely on some instruction off the Internet for this job.

athomp121

Did you ever get this fixed or figured out? I am having the same issue with my 2005 Acura TL.