ECM 2.4L 2002 Santa Fe

I'm not convinced you have an ECM problem. In fact, I think it's unlikely. I also don't know what specifically you're doing to attempt to induce a trouble code.

Based on your description, I'd recommend checking potential mechanical issues. Since you've verified the fuel pressure (presumably with a gauge), I'd recommend checking the camshaft timing and the catalytic converters. Improper cam timing or a clogged converter will cause the issue you're having.

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I have doubled checked the cam timeing and crank sensor (new belt new sensor).The car was running good and all at once it slowed down and would not pull.The only bad reading I can find is the mass output volts (0 volts ign on eng not running)I get 1 volt of which the manual indicates bad mass or comp.I don't think the cat. would stop up that quick.The car is about 300 mi. from me and at the time all I had was a code reader.I disconnected the map sensor and went through about 5 crank cycles the eng ran the same but I never got a code.I am back home now and getting a laptop to go back and try to get a better read out.I have read that some of the ECM (92-96) had faulty capacitors and would give problems after (5yr).I am a retired mechanic and this is my daughters car.The eng has new plugs,1 new coil and new timing belt.I hope when I go back the laptop will get a better reading.

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It was a completely different car and a long time ago but a similar symptom. I tried everything imaginable before someone told me it must be a plugged cat.

It was a plugged cat.

Old_timer

In regard to the coverter, it all depends on whether a chunk suddenly fell out.

The MAP sensor is used only for checking proper purge activity. The MAF is used to determine air flow, and is a major input to the computer's operating strategy. Still, I wouldn't suspect a MAF sensor as a likely candidate in this case. They don't tend to fail suddenly, but rather tend to skew their results over time, typically resulting in a fuel trim type code.

I can count on one hand the number of Hyundai engine or transmission computers I've had to replace because of a fault within the computer, and all were either made well before (think 90-94 Excel--Mitsu) or well after ('06 and newer-- Delphi) this Santa Fe was produced. I agree it's a nonzero probability, but it's low enough that replacing the computer should be a last resort only after everything else has been verified or ruled out.

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I knew the map sensor was not the problem.I unplugged it to see if I could get a fault code after about 5 crank cycles of which I did not.I have done numerous test on other ECM and got codes with that action on other autos.My question was is why I can't get a code out of this ECM that way.These crank cycles were at normal temp.

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I'm not sure why this doesn't produce a code. I'd think it should. But you also shouldn't condemn the ECM because it doesn't. It'd be a costly low-percentage guess.

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