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I just got a check engine light today. I pulled the codes and they report back as P0135, P0141, P0155, P0161. Bank 1 and 2 and Sensor 1 and 2 heater malfunction. Since it is unlikely all 4 sensors went bad at once, I assume there is something else. I checked the fuse in the engine bay fuse box for the Oxygen sensors and that looks good. I've had this car since April and this just appeared. I've also had a rough idle condition since day one that I've tried fixing with no luck.
Is this is a common issue on these cars with an easy fix? Just wishful thinking.
First off what year is the car ??...there are some wiring differences in some model years. Looks good is not good enough when it comes to diagnosis...I would check it with a multimeter or replace it and recheck...depending on your year all 4 ground wires meet at a splice pack which can be accessed after removing the battery and the tray it sits on...the ground for that splice pack goes to a body ground which is near the left front O2 sensor...the ground is on the engine block...you can start there !!...BTW if you have a test light you can connect it to battery positive and probe the wire going to the engine block..the light should illuminate bright if the ground is OK...I prefer using old headlight bulbs to “load” these ground wires...resistance checking is not the way to do it.
Ah sorry. It is a 2001 base model. I did test the fuse with a multimeter and it has continuity. No corrosion on the legs of the fuse or in the socket that I can see. So it can very possibly be a ground issue?
Mine car is also an ‘01...all 4 O2 heater circuit grounds go to that splice pack and then another wire there goes to that body ground (G105)
. I’d pull the top of that splice pack off and see what the “comb” looks like...check for corrosion...as far as the power side of the heater circuit power comes in on the brown wire for all heater circuit so you can turn the key on and see if you have 12 volts there...I would check 2 !!...The comb looks like what is circled in the picture...this is one of the splice packs near the BCM. Not a difficult problem to diagnose.
It's been a while but I've been pretty busy so I just got to this today. I checked the splice pack and that looked look. The comb was clean and so were all of the contacts inside the splice pack. I still need to check the ground on the engine block and will report back. The brown wire you mentioned to check for 12 volts, that is the brown wire going directly to each O2 sensor?
An update. I finally got time to get under the car again (and my emissions test was coming up this month). I got the engine ground off the block, even though it was torqued to a million lb ft. I used a high grit sandpaper on the block, the O2 ground eyelet, and the strap. Also test one O2 sensor on each side, both were supplying about 12v volts with key on. Put it all back together, cleared the code, then went for a 30 minute drive. The emissions readiness monitor showed each system show complete one by one, including the O2 sensor heater. So I went and got the emissions test right then and it passed. Hopefully this resolves the issue, even though the ground didn't have much or any corrosion on it.
You don’t have to have a lot of corrosion on these grounds for it to not work...I had my horn not working and when I went to diagnose it there was just a little oxidation on the power wire that goes into the horn membrane...a little emery cloth was the fix !!
All four O2 sensor heater codes
