I just got my Auto Trans. replaced last week under the 100K guarantee extension. It was replaced because it of a small “shock” when changed from D4 to Reverse. They said the Trans Diagnostics confirmed an “54 WH93”. I checked the Accord Service Manual (98-2002) but couldn’t find this code. Anyone knows about it?

Anyway, before the transmission was replaced the only other symptom I noticed was something like this: The car (Automatic Trans) sometimes, at least 1-3 times a week, and when I come to a sudden stop (like signal lights) the RPMS goes very slow like 250; then the car starts to rattle as if it is going to turn off. But when I pressed a little on the gas pedal everything goes back to normal (over 750rpm). The proble is that after trying out the new transmission this weekend the problem seams to persist. Does anyone know where to look for this problem?

For reference my car is:
Accord Coupe 2000 (4i)
Transmission: Auto
Mileage: 95K

 

My transmission does this all the time. When I shift from D4 to reverse, I hold down my brakes until I know the car has shifted. If I let go too early, I feel that small jolt.


This sounds like a throttlebody / egr valve issue. When the exhaust gas recirculation (EGR) valve is jammed, high amounts of exhaust recirculate though the engine. It'll give the exact same symptoms you're describing.

 

That's definitely not a DTC code...no idea what that is.

Sounds like EGR.

 

I recently cleaned the throttlebody, so I will check for the EGR valve instead. It’s common for this to happen without the engine light on with this amount of Mileage? I think last month I got an engine light indicator but the code gave me “MAP Sensor”. I check and cleaned the sensor, then reset the ECU and till today no engine light for me.

Does this valve easy to replace? How can I check for malfunction on this valve? Approximately how much should it cost?

 

well what's the DTC?

 

At this time I don’t have DTC code. I did have one when the MIL came on. But the code was related to the MAP sensor, I think it was (5). Anyway the problem I’m trying to solve is the low RPM issue when the car came to stop (e.g. Signal Lights, Stop Sign). The “54 WH93” code previously posted, was the error code supposedly detected by Honda to make a claim under the extended transmission warranty.

The transmission was replaced last Friday, and I was hoping the low RPM issue to go away. But it seams to be there. I only have a symptom, so I need possible causes to check them and troubleshot my car. I know some sensors can be checked by measuring voltage fluctuations and other DIY stuff.

 

Well if there's no DTC we can't help you with that. As far as the EGR, Honda has an 80k mile warranty on that. It's not that difficult to clean out yourself and a can of seafoam might do the trick.

 

I know it’s difficult to diagnostic a problem without a DTC code. I just want to know possible causes for this type of symptom.

Don’t take it wrong, the transmission was replaced for other causes which are no longer on my car since replaced. I was hoping the low RPM problem will go with the Transmission replacement. But after the Transmission was replaced by Honda, this problem still persists. Honda could not do anything about this specific problem since they can not replicate it, when testing my car.

Here is a summary:

Symptom / Info:

1. At least 1-3 times a week, and when I come to a sudden stop (like signal lights) the RPMS goes very slow like 250; then the car starts to rattle as if it is going to turn off. But when I pressed a little on the gas pedal everything goes back to normal (over 750rpm). It’s like the car is chocking or like when you depress the clutch pedal on a manual without pressing the gas. At first I was under the impression that it could be transmission related because its seams like the car is in “2nd” gear and could not switch to “1st” until I press the gas pedal.
2. My car does not have the Check Engine light on.
3. My car exceeds the 80K extended warranty on EGR (95K at the moment).

As some of you pointed, this could be related to the Throttlebody / EGR but:

1. How probable is that it could be the EGR valve?
2. Does cleaning the throttlebody with seafoam automatically clean the EGR valve?
3. Is there anyway to isolate and test the EGR valve for malfunction?
4. Is the EGR located on the “throttlebody” (view diagram below)?

 

Disconnect a vacuum hose, suck up 1/3 can of seafoam according to instructions that can be found all over HAN, then come back and tell us if it's still happening. It's very cheap and can only help. You sound like you have a lot of carbon build up somewhere. If the EGR valve was 'malfunctioning' you would get a DTC, but if it's just clogged you might not.

The thing you circled is the IACV. The EGR looks like a little canister sitting on top of an engine platform, has an electrical connector coming into it and no vacuum lines.

 

Are you referring to the instructions for cleaning the Throttlebody with seafoam?