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Old 08-20-2013, 10:05 PM   #1
supraheelfan
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Default JDM vs. USDM ecu (yellow plug)

I bought a jdm 7m a while back and the car has only ran trouble free for a couple months. I have a usdm engine harness (a/t) with usdm ecu (m/t) that originally came with the car. Code 52 will not go away even though it has NEW wiring, perfectly fine sensors, brand new sensor connectors and a strong ground. The two transparent knock sensor wires going into the ecu have been re-pinned and it has a strong connection. Now, should I just buy a jdm yellow plug ecu for this car to actually run without problems or is this not my problem.
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Old 08-20-2013, 10:08 PM   #2
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I have found a jdm a/t ecu and I have a/t engine harness already in the car. Would it be worth it to at least try this jdm a/t ecu with the usdm a/t harness in the car?
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Old 08-21-2013, 12:26 AM   #3
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Unless the sensors are different (which I HIGHLY doubt. As far as I know only the oil sensors are different/incompatible) and you used the JDM sensors instead of your old USDM sensors OR the ECU is damaged (in which case any ECU swap will probably correct the problem) then the JDM ECU isn't going to change a thing.

I suppose that a severe knock may cause a code 52 as well if the knock is so bad that the ECU thinks the sensor must be crazy.

So you've replaced the old wiring with new wiring or did you just put new pins on the old wiring? The old wiring has been found to be the most common failure point in this circuit.
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Old 08-22-2013, 12:15 AM   #4
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Yes, there is new wiring all the way to the sensors. When I bought the engine i had to replace one of the knock sensors with a used one I bought from supracarparts.com. I didn't think the knock sensors would be different (jdm knock sensors vs. usdm knock sensors) because i've yet to hear anybody else with this problem.
I have also been told by the shop that I'm using, that they checked the ecu voltage and they say the ecu is not the problem.
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Old 08-22-2013, 12:21 AM   #5
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The entire wiring of this car has been a nightmare from the very beginning.
So it has new wiring, strong ground, both knock sensors work, the connection to the ecu is very tight and strong. I'm just out of options it seems.

It has jdm engine, usdm wiring and ecu, with one jdm sensor and one usdm sensor (i guess)
ok so you say if engine knock is bad enough it'll set off CEL anyway, do you have any idea of how I could check excessive knock?
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Old 08-22-2013, 06:31 PM   #6
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I shouldn't have mentioned the knock thing... It's supposition. It would have to be a very eccentric knock or noisy signal for that to occur and I think you'd know by then that something was very wrong.

How did you rewire the sensors? Did you follow the SOGI rewire?

You say the sensors are fine and have been replaced yet you say one is USDM and one JDM... But they're both new? I'm a bit confused here. How did you test them?

You could open up the ECU and look for bulging/leaking capacitors. The best bet would be to try to find one you could borrow or rent. Unfortunately, I gave away the box I had of half a dozen of them a year or two ago or I'd just send you one.
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Old 08-22-2013, 08:38 PM   #7
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I didn't do the rewire myself a shop here locally did it. It's the second time they have done the rewire. Once with the original harness (problem was solved). Then I had this used auto harness swapped on the car and the code 52 came back so I had them do the rewire a second time, as well as check the actual sensors again. the problem is still here the only reason i said the sensors could be jdm and usdm is because one is original to the engine and one is not. For all I know they are the same.

I mostly wanted to see if anybody has had this problem and if a jdm engine needs a jdm ecu?
Also, why am I having such a hard time getting rid of this code 52? All the tsrm procedures have been performed by myself as well as other more qualified mechanics, but to no avail.
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Old 08-22-2013, 10:49 PM   #8
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Three things cause a code 52 (barring the really out there shit): bad sensor(s), bad wires, bad ECU. No the USDM ECU isn't the issue. I suspect the rewire didn't work and needs to be redone. The knock sensors could be shot (even if they were tested) as they're very delicate things and they really aren't all that easy to test (most shops, even Toyota's will tell you to just replace them at this age).

Here's a link to the shielded rewire which solves this problem for most owners: http://oldschool.supracentral.com/htm/knock.htm
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