ecu unusual problem? - Honda Prelude Forum

preludeh2394 · 03-04-2011, 02:07 PM

ok guys so this is a jdm h22a obd1 swap 94 prelude.

so i have the usdm ecu ever since i finished the swap it ran fine and good. i finally got a hold of a jdm ecu. i bought it and exchange the two ecu. usdm out and jdm in. than i started the car with the jdm ecu in and the car idles and there is CEL code 41. which is another code for heated o2 sensor. anyone know any thing about this

Rapid Prelude · 03-19-2011, 02:14 AM

First of all going with a JDM ecu was a mistake...

You should have kept your USDM ecu, because the JDM ecu governs your speed at 112 MPH
(unless your speedo went to ****, and you got a gps like me

but i fixed that.)
As for your code, are you absolutely sure its for the o2 sensor? Does your car have ABS, and 4WS? if it does not have one of those, that ECU might be throwing a code for it.
Im sure you know how to pull codes off the OBD1, right?

Rapid Prelude · 03-21-2011, 02:35 PM

Code 41 in the engine management side is Heater O2 system BUT it can also be a 4WS code too.

preludeh2394 · 03-21-2011, 09:34 PM

Quote:

Originally Posted by Rapid Prelude

First of all going with a JDM ecu was a mistake...

You should have kept your USDM ecu, because the JDM ecu governs your speed at 112 MPH
(unless your speedo went to ****, and you got a gps like me

but i fixed that.)
As for your code, are you absolutely sure its for the o2 sensor? Does your car have ABS, and 4WS? if it does not have one of those, that ECU might be throwing a code for it.
Im sure you know how to pull codes off the OBD1, right?

i still have my usdm ecu.
and yea i know it governs the car. but i can get it take it out. i heard that jdm ecu has a bigger something to make the jdm motor run better. also it has a higher redline limiter compare to usdm.

and yeah code 41 said its heated 02 sensor,
yes car has ABS, but NO 4ws.

Rapid Prelude · 03-21-2011, 11:30 PM

Quote:

Originally Posted by preludeh2394

i still have my usdm ecu.
and yea i know it governs the car. but i can get it take it out. i heard that jdm ecu has a bigger something to make the jdm motor run better. also it has a higher redline limiter compare to usdm.

and yeah code 41 said its heated 02 sensor,
yes car has ABS, but NO 4ws.

Thats interesting; i haven't heard that before. What does your engine red-line at with your USDM ecu?
My car has no ABS or 4WS so i got a constant three codes.
So that means your code 41 would most likely be due to no 4WS would be my guess. I would see what exactly the options that the JDM car would have had when it was pulled. Look up the numbers on the side of the ecu and google them.

preludeh2394 · 03-22-2011, 08:42 PM

Quote:

Originally Posted by Rapid Prelude

Thats interesting; i haven't heard that before. What does your engine red-line at with your USDM ecu?
My car has no ABS or 4WS so i got a constant three codes.
So that means your code 41 would most likely be due to no 4WS would be my guess. I would see what exactly the options that the JDM car would have had when it was pulled. Look up the numbers on the side of the ecu and google them.

yeah but the ecu is made for the 2w NOT 4W thats why on the ecu it said
2w on it.

with usdm it red around 74-7600 not sure. jdm is 8000 i think

Rapid Prelude · 03-23-2011, 12:43 AM

Then i would double check your o2 sensor is working correctly, if not replace it.
That JDM ecu does red line at 8000.

preludeh2394 · 03-23-2011, 01:17 PM

Quote:

Originally Posted by Rapid Prelude

Then i would double check your o2 sensor is working correctly, if not replace it.
That JDM ecu does red line at 8000.

yeah thats the problem, cause i only get the cel on the jdm ecu, if i put the usdm on the cel goes away

Rapid Prelude · 03-23-2011, 10:12 PM

The JDM ecu might still be trying to adapt to the different climate. If your above sea level, it going to have to re-learn a little bit. Thats what i think.
It was nice chatting though! lol