O2 sensor heater not ready?

hear

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First off, I have a 97 and I'm not in California....this topic is discussed to death around a TSB and CA emissions on 2005 & 2006 models.

I took my thing to get inspected yesterday, and aside from the CEL bulb being burned out, I unexpectedly had 3 not ready codes: Catalyst Not Ready, O2 Sens Not Ready, and O2 Send Htr Not Ready. I check my codes from time to time and I've never seen (that I can recall) anything related to the cat or o2 sensors being an issue, so it is very surprising that I would now suddenly have these be in a not ready state. I haven't had to clear any codes in months, and I've driven the thing plenty in the meanwhile...around town a bunch and then several 2hr drives to go wheel, which is to say I'm sure I've completed the "drive cycle" by now.

The only thing out of the ordinary is that over the past 5ish weeks, I've hardly driven it at all. Really, I've only taken it on one 20 minute drive and then the 5 minute drive to the inspection place. Is it possible that my lack of driving it over the past month is a factor in making the sensors read not ready? Battery was connected the entire time as well, that seems relevant. Really, it just sat in the garage, waiting to be driven.

But perhaps more importantly, is this indicative of some other issue? Is it actually telling me the o2 sensors are bad? Is there a heater circuit I need to investigate? The internet is very quiet on this (again, unless you have a 2005-2006).
 
Have you checked the wiring leading to the cats for damage? Like damaged/burnt insulation? The white wires are for the O2 sensors heaters.
I pulled back the rubber "jacket" on both sides and they look a-ok. (seems like every other connector has frayed wires, so I know what I'm looking for). Really there is no sign of any damage on either o2 sensor wire.
 
I guess the O2 sensor's heater wiring color codes changed according to the FSM, they're no longer both white as they were on my early '97.

Check that the O2 sensor's dark-green wire with the black tracer has +12v on it (from the ASD relay) when you first turn the key on. That 12 volts will shut off 1.8 seconds later if the engine isn't started. Then check to see the brown wire with the yellow tracer gets grounded to turn the heater on, that ground is provided by the PCM. The O2 sensors receive a constant +12v on the green/black wire when the engine is running, the heater activates when the brown-yellow wires are grounded by the PCM.

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Fantastic troubleshooting steps, thanks. One question, when you say check the voltage on a wire, you're really saying unplug it and probe the inside of the connector, right? Or do I need one of those fancy probes that comes in from the back side of the connector?
 
Fantastic troubleshooting steps, thanks. One question, when you say check the voltage on a wire, you're really saying unplug it and probe the inside of the connector, right? Or do I need one of those fancy probes that comes in from the back side of the connector?
Yep you can just unplug it and probe the inside of the connectors. But the connectors might be hard to get apart so you may have to probe from where the wire enters, you can probably reach the back of the crimped connector from there.
 
"and then the 5 minute drive to the inspection place." I dont think 5 mins is long enough to get things heated up good. Thankfully smog checks are a thing of the past but when we lived in Commiefornia the rule of thumb was to run it hard up the freeway for 15+ mins before hitting the smog shop.
 
Then check to see the brown wire with the yellow tracer gets grounded to turn the heater on, that ground is provided by the PCM. The O2 sensors receive a constant +12v on the green/black wire when the engine is running, the heater activates when the brown-yellow wires are grounded by the PCM.
Sorry @Jerry Bransford one more question: the brown/yellow wire gets grounded after the 1.8sec, or only with the engine running, or some other combination?
 
The ASD relay shuts off after 1.8 seconds if the engine doesn't start. It shutting off kills the ground to the O2 sensors. If the engine is running the ASD relay remains energized (on) giving the O2 sensors a steady ground.
 
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wondering if you solved this problem @hear

I’m having similar issues.

I did. I ended up having a number of wiring problems in the section of the harness behind the engine/over the trans, missing insulation & broken wires. And also a melted wire behind the dash & some wrong sizes fuses.

Sorry I don’t have a simple fix for you.