A1 and a4 harness differences?

f20bcg3

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Hey guys ran into a problem i did search but came up with nothing (maybe i didnt search right )but do you all know if there are any major differences between the ulev engine harness and the non ulev harness?
I know the ulev runs a different o2 sensor and different ecu... any other major differences?

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danmccormick87

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I think that's the only difference, I might be wrong. The 02 sensor in the front bank is a wideband, hence the ULEV status, and ECU is programmed to read that.
 

f20bcg3

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But i got a buddy that says his didnt plug into his fuse box (engine bay) trying to figure out if they sent him the wrong harness and they trying to get him for restock fee

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f20bcg3

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He got a a1 engine a4 harness


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danmccormick87

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I'm still thinking the it's the only difference. The wideband allows for a better ratio by the ECU, hence making California happy. Found this post on another forum:


Sorry, I was away for a while guys. The ONLY difference between the A1 and A4 is the exhaust manifold and the valve cover(only ascetically). If you put the A4 engine in an A1 equipped Accord, you are fine as long as you put the A1 Exhaust manifold on the A4 block, in which case you would not change the ECU. The intake manifold and throttle body match between the 2 engines, so you can even save yourself some work there if the A4 already has an intake manifold on it.

Only thing I can find is that the ECU is a 32 bit, has a different manifold for the wideband style O2 sensor, and of course the different O2 sensor.
 

Build-It

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Hey guys,
Im the guy that has the ULEV harness. Please take a look at the pic in my profile. There you will see that the ULEV harness has a different connector compared to the VTEC side. These to connectors are supposed to connect together, and mount under the fuse panel
The ULEV has many more wires and some of these wires do not cross over to the VTEC harness, not to even mention that one connector is almost round in shape, and the other is square!
 
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