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1996 Del Sol Si 491k miles D16Y8. Failed CA smog check. No OBD2 codes. Runs well.
I suspected a bad primary sensor heater so I went through the FSM procedure and you can see the results below. I did not reset the ECU as there were no codes. It appears that the ECU is not grounding either of the heaters.
I inspected the circuit board and found no visibly damaged components. I pulled the connectors apart and jumpered all pins through except the heater ground which I ran though the meter and read zero amps. I plugged it back in and used a inductive current meter and again measured no current. I verified all functions of my Fluke 77 meter and current clamp.
Does this really mean the ECU is bad or could there be something I am missing? Has anyone experienced a ECU failure like this?

Also I'm open to any thoughts on where to look first to fix the smog test failure.

 
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Update: The FSM specifically states to turn the ignition switch to the "On" position and there is no voltage. However when I turn the engine on, I measure current. The heater is not the problem.
What made me check this is that I've read in a few online posts that the ECU only closes the ground circuit when there are no codes and the engine is running.
Is the FSM wrong?

Also I have measured the resistance of the other heater element which I replaced with aftermarket at the same time long ago and it's 13 ohms. That's in spec but the primary sensor is 9.5 ohms. Is only 0.5 ohms bad enough to cause a problem? Wouldn't that just make it hotter?

 
Rep Power: 222

What brand are the o2 sensors currently in the car? Honda's are very picky with sensors and electronics.
What do the smog results say?

 
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The smog results are in the photo in the OP.
I replaced both the O2 sensor 2016/05/18 with a Bosch 13007.

 
Rep Power: 222

Sorry missed that earlier. Can't use bosch, needs to be Denso or ntk

 
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They worked back then, but maybe they just don't last as long. And I see many people in the forums bashing Bosh so it's probably worth a try. After I inspect the cat I might just try give it another attempt at inspection before opting for the $200 in NTK. I have done other tings including cleaning the injectors so, maybe I'll get lucky.
Thanks for the advice.

Does anyone have any experience with the ECM that could commend on whether they ground for the heater is open when the ignition is on but the engine is not running?

 
Rep Power: 244

Yeah Bosch sensors don’t work in Hondas. How much was the one you got? Typically people go for the cheaper one and it doesn’t even have the correct range or the heater circuit is on the wrong pins.

 
Rep Power: 367

don't know how much it impacts the 6th gen cars, 7th gen are a real pain for electronic sensors, might be a tuning in the ECU that honda does that goes out of the range of aftermarket versions.
might have worked so far, but in case you replace, try to get a OEM one.

 
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Makes sense, cheaper is often a false economy. Having said that, I got my money's worth out of them at $35 each. I have usually used OEM parts on this car up until a few years ago. It is 491,000 miles and $800 for OEM doesn't make much sense given that's about what the car is worth. I do see I can get a pair of NTK, whom manufactured the OEM, direct fir for about $200 at AutoZone, so I might try that. Thank you all for chiming in on the Bosch sensors.

Can anyone confirm that a healthy ECM doesn't close the heater circuit until the engine is running?

 
Rep Power: 367

reset ECU first? I do not know the answer to your question, BTW

 
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I did reset the ECU. Thank you.

 
Rep Power: 222

Rockauto has ntks for $50 Canadian and Denso for $37

 
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It unsurprisingly failed again so I'll likely try that next and then use the known good O2 sensors to try and figure out if the cat is dead. I looked and the OEM one is no longer available from the dealer and the CARB compliant version from Magnaflow is $1440. So time for some troubleshooting.
Thank you all for yoru help.
And thanks for the shopping tip

 
Rep Power: 222

Also long as you don't have a p0420 and the car runs and drives fine the cat should be fine. Look for guys parting out out cars and grab a cat if you still feel you need one