So I finally finish a long-awaited intake reseal along with the coolant hose that hides down in the valley. Gave everything a nice cleaning, the works. The car has been unused since last November, as we don't bring it out. Never saw a winter, never will.

Fast forward to today and the original issues are fixed. Confirmed via smoke test and the lack of the P0174 code. Now, however, I have 3 new codes. Yay. P1000, P1646 & P1647. I know the P1000 is the car waiting for readiness. The 2 for O2 heaters simultaneously is, to say the least, odd. I checked for voltage at the fuses for the heaters to see if that pesky little relay under the fuse box was sending voltage to them and it indeed seems to be.

Did the car get fussy from sitting? I performed a hard reset, but no change. The battery did go down fairly low at one point in the past few months, but it's been brought up to 12.9V now(It's an 8-month-old Exide). I'm kind of at a loss here and I don't just want to throw parts at it. Bonus issue was the ABS & Traction control lights on that initially came with random throttle cut, although the lights are still on, the throttle cut is gone now) Just replaced one ABS sensor and I'm going to do another next week, as my little OBD reader actually coughed up a C-code for the left rear sensor! Go figure.

Thanks in advance. In my lurking, I've come to realize what an incredible wealth of information this board has!

 

How many miles on the clock?
Many consider them to be a wear item, much like spark plugs.
Replacing them after a hundred thousand miles, along with the plugs, & coils.
Might try running it a while as long as your check engine lite isn't on.

 

It has about 135k. I figured that they were getting on in years, but thought it odd that the codes weren't there before the winter and then showed up only after the work I just did. Did I not plug something in somewhere maybe? Good point on the coils. Plugs are new, but I was considering new coils due to age. We have started driving it more now that the bulk of the work is done. Maybe a drive cycle needs to be met?

 

You could check the ohms of the O2 sensor heaters but chances are the sensors need changing.

It can't run the car even remotely right with those DTCs so ignore any gearbox or other faults until those DTCs are fixed. It will default to running rich to avoid engine destruction if lean, but will damage the cat(s) gradually as a result.

 

I'm going to try and get some readings this weekend. I'm not so sure that it's running rich, though, as the codes are for the heaters themselves. I'll be getting fuel trim numbers soon, as well.

 

It has to run rich because it can't trust the O2s and dare not run lean. The unfixed DTCs force that.

 

Makes sense. I just assumed that because it was the heater circuits that the actual reading capabilities of the O2s weren't being compromised, at least that's what a few posts here seemed to imply. I'll let you all know when I run some more tests. Thank you for the input!

 

I would not start throwing parts at it off the bat... both upstream heaters would not likely have failed from sitting for 6 months. My guess would be a cut/chewed wire. The heater relay is a good check to make since it's one of the only common points for these 2 circuits. Test for heater voltage at both O2 sensor connectors. Quickly looking at the schematic, the heaters for upstream are fed by circuits 142E (B1/S1) and 140E (B2/S1) and the ground is PCM controlled. 142E is fed by F33 and Relay R12. 140E is fed by F34 and relay R12. Relay R12 is fed by the same source as everything PCM controlled, so that likey still has a supply voltage.

 

I thought it odd that they'd both go, as well. As you indicated, R12 and fuses 33 & 34 do have 12V. That was my very first inclination. I'm going to get her back on the ramps to perform some testing at the plugs.

Do you think it's possible I did something during the teardown for the intake gaskets? It's highly coincidental, no?

 

Definitely check for 12v at the connectors, and that it can support current of 1-2A (test lamp for example). Going to be difficult to test the PCM ground, but cross that bridge when you get there. The PCM wiring is at the rear of the engine, that would be the only thing that would have been disturbed during an intake removal. Did a lot of coolant spill over on the rear of the engine?

 

Hrrmm.

I did have issues pulling the wire bracketry up to the intake because I goofed and plugged in the vacuum line for the brake booster prior to the wires. Snapped that sucker right off on the back of the intake. Heck of a time finding that part. All set now. Anyway, maybe something happened then. Wasn't a crazy amount of yanking, but who knows. I'll verify the voltage and then the continuity if need be. At least I know the wire colors and their approximate location.

I'll report back, likely when it's a touch cooler out! Thanks again.

 

Just an update.

I confirmed that the primary O2 sensors are indeed getting 12V to the heaters. They are both reading the correct resistance, as well.

My theory is that it needs a drive cycle. The readiness status shows that there are 4 tests not completed. Of the 2 that are,1 is the Heated O2 test!! It just makes no sense to throw money at parts that I believe won't do anything. Maybe I'll eat my words in the near future, who knows!

Off to do a drive cycle test, or two, and see where that leaves me. Will update soon.

 

Just got back from the drive cycle test. I cleared the code initially and had only the Fuel System Monitor and the Heated O2 Sensor tests passed.

After the run, I added the EGR and Misfire tests to the passed column. Comprehensive Component, Catalyst, Evap and O2 are still Incomplete. I shut down and cleared the codes and all of the monitors reset as expected. I almost think I'm willing to pick up a pair of O2s just to rule them out. They've gotta be originals. Maybe.

 

The 04's are a good bit less expensive than the 07's are.
Still looking for a set of them for a better price, but the Denso's seem to stay pricey.

 

Looks like Rockauto has the upstreams for $101 and the downstreams for $54.

 

DENSO 2344951 {#C2C22679} Info
Downstream
$68.79



DENSO 2349125 {#C2P8810} Info
Upstream
$85.79


Add to CartAdd to Ca


$330 + shipping, for two of each with the sales tax included for $330
A lot of money for me
Prices you saw are for 04's

 

I found my BT ELM adapter and fired up the Torque app. I found out so far that the car won't go into closed loop due to 'low temp'. Coolant temp? That's fine. O2 heater temp? Maybe. Also noticed that the primary O2s won't give out any readings. The rears go between 0V and 0.05V. It would be so easy to replace all of the O2s, but damn I'd hate myself if I still pulled the codes afterward!

 

I'm confused Wingrider, as I have an '04!

 

I also have an 07, and those sensors nave not been replaced.
Believe this price may be lower than last time i looked at them though.
The ones on the 04 have been replaced, seems they cost me less, about $250.
But can't find the receipt to be sure.

 

Ah, I got you now! Lowest price I found for mine was from a UK seller on ebay. He had all 4 for $270 shipped. About $55 less than rock auto.

I'm still on the fence as to whether I should just bite the bullet and get them. Decisions, decisions!