This morning and afternoon my odb reader lit up with tons of sensor failures and shorts. The car seems to be running fine and was driving fine on the way into work.

ive been trying to track down a small battery drain, ~70mA, and in the process I cleaned all of the grounds, replaced the battery terminals, cleaned and checked fuses, alternator, starter, etc.

fire it up yesterday and I get a Solenoid circuit short code. Then this morning it’s the O2 sensors, and the circuits shorting, then in the afternoon it’s the transmission shifting circuit shorting, then the catalytic converters, oil temp, an so on!

ive checked many of these things and they seem fine, no obvious damage, can measure some in fact still seeing power in certain cases...but every time I turn it on and check I get more codes! Is this just the computer failing on me??

 

You got a lot of stuff failing down below. Did you inspect the wiring harness (pull it apart) in it's entirety?

 

Go back to the work you recently did. You will likely find something loose or incorrectly done.

Ron

 

Not in its entirety, I was checking the initial ones popping up and there’s no obvious damage, but then suddenly 14 sensors failing at once so I stopped believing it was each of these suddenly dying/shorting.

ive been doing this work over the course of the pst week. the only thing I did yesterday before all of this was replace the battery terminals, it was running and driving fine otherwise

it’s possible but I wouldn’t even know where to begin

 

In re: the parasitic drain, did you disconnect the starter? Disconnect the PDC?

 

Check the loom in the front doors and rear hatch?

 

I disconnected the starter and still saw the drain, same with the alternator. Didn’t do anything to the pdc beyond pulling fuses

i have not checked any door looms, but non of the lights stay on when the doors closed so I figured I was good there

 

Something is likely shorting to ground, possibly the supply voltage to the sensors. Common places to look are the harness as it transitions from the head to the firewall, and anything near the exhaust such as the CPS and the O2 sensor wiring. The engine and tranmssion computers are two separate boxes, btw. It's also possible you caused some of the codes by pulling fuses. It's rare to have one of the computers die, and usually when they do it's kaput and not intermittent.

 

Any wire that is hot all the time is a potential source. Interior lights, brake lights, headlight switch.

IMO you should check those looms because they frequently fail.

Disconnect this wire, then see if the green wire or the PDC is the source of the leak:

 

I would take something with an error code (the oxygen sensors) and follow them in their entirety to power, to ground and to the PCU. A pile of sensors have a common ground. Searching for that schematic, I think the short may be a ground or signal to power (different from power to ground).

 

 

Do you have ABS? 4 oxygen sensors? What exactly are the codes?

 

Ok, I followed all of the wiring, to ground to pcm to pretty much every sensor I could get eyes to and I don’t see any exposed wires or anything damaged or not even covered in the plastic wire covers.

ive checked all the grounds that I cleaned last week and all seems fine with those, too

re drain: I removed that red wire to the pdc and the drain disappeared! Reconnected it, and it’s back. So it’s just following the hot wires from there?

no ABS, but yes 4 O2 sensors

codes are:
p0705 (x2)
p0136
p0443

weirdly all of the other 12 codes are gone now

 

In the other thread you said you pulled all the fuses. Did you pull all the relays? Is there a drain when red is connected to green, bypassing PDC?

Check the NSS. Do you have reverse lights? Starts in N and P? Shifts OK? Check all that wiring.

For now.

 

Yank out Fuse 10. All that stuff looks to be on the same circuit.