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Discussion Starter · #1 ·
Hey there all.

I am a noob, but a relatively fast learner and pretty handy.

This is my intro post:
https://www.passatworld.com/forums/...ost-make-entry-thread-v2-117.html#post4510377

That gives a good intro to why I am here without retyping everything.

Anyways, I did a bunch of work to fix the following codes:
P0117 Engine Coolant Temp.Circ Low Input
P0155 O2 Sensor Heater Circ.,Bank2-Sensor1 Malfunction
P0300 Random/Multiple Cylinder Misfire Detected
P0301 Cyl.1 Misfire Detected
P0302 Cyl.2 Misfire Detected
P0348 Camshaft position sensor
P0441 EVAP Emission Contr.Sys.Incorrect Purge Flow
P2096 Fuel system too lean
No Heat

ECT sensor, o2 sensor, all spark plugs, all spark plug wires, valve cover gaskets, camshaft position sensor and purge valve were all replaced.

Engine put back together, oil added, coolant added. Took it a bit initially but fired up and since then its fired up on the first try each time, but temps haven't been too too cold (32F or so, not like -10F).

All codes were cleared and it was driven around for a while. None of those codes have come back. for a quick minute got two different cyl. misfire codes but then self cleared. Right now I am getting a p0150 code O2 Sensor Circ.,Bank2-Sensor1 Malfunction

The only difference is the word heater in the codes. but same side and sensor.....the sensor is new.

My plan is to try swap the connections between banks one and two, and see if the code switches sides or not. If it doesn't switch sides I gotta think that its a wiring issue between the sensor (I will check the contacts too) and the computer.

so again I went from
P0155 O2 Sensor Heater Circ.,Bank2-Sensor1 Malfunction
to
P0150 O2 Sensor Circ.,Bank2-Sensor1 Malfunction
after replacing the sensor

any thoughts?

I plan on doing a heater core flush this weekend to see if that fixes the heat problem before trying to take the dash apart.

Thanks in advance. hopefully I didnt make many posting/noob mistakes.
 

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1,953 Posts
Not sure about the codes but have you serviced the PCV system? They get clogged and will make your valve covers leak again. The plastic hoses (along with the tiny vacuum hoses) are brittle also. It's best to replace them with silicon. Both systems can create rough idle and codes if broken.

As far as not having heat. The system needs to be bled to remove any air pockets. Reverse (or back) flushing the heater core is recommended. Make sure you use the pink coolant and water ratio. Never mix different coolants and always make sure it's G12.
 

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Discussion Starter · #4 ·
Thanks. In my post I said I fixed all the sensors/problems associated with all the codes that were present at the time of my adoption of this car.

I'm not worried about bleeding the system and a back flushing the heater core because of these two threads:
https://www.passatworld.com/forums/...f-youre-singing-i-aint-got-no-heat-blues.html
https://www.passatworld.com/forums/b5-information-base/330868-v6-coolant-flush-diy.html

So the TL:DR version of my OP:
I went from
P0155 O2 Sensor Heater Circ.,Bank2-Sensor1 Malfunction
to
P0150 O2 Sensor Circ.,Bank2-Sensor1 Malfunction
after replacing the sensor (drivers side, upstream)....do these two codes not point to the same sensor?
 

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Discussion Starter · #6 ·
If you replace a part and still get errors, the first question is what brand, model, and source of the replacement part? Sounds like the system can't "see" the heater on the new sensor.
30 dollar o2 sensor from amazon. https://www.amazon.com/gp/product/B07DHLT3GL

I am going to swap the connections this weekend for the Bank1 and Bank2 sensors (way easier than swapping the sensors) and see if the error moves sides or stays put.
 

· PassatWorld Elder
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I would look at the connections on the O2 sensors. There may be corrosion preventing a good circuit.
 

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Discussion Starter · #9 ·
hit all the contacts with some MAF cleaner since I had bought some to do the MAF sensor. Much happier motor now.

PCV check valve (not purge valve) should be in today and that should knock out the only remaining issue of both sides running too lean, unless something broke - at which point, junk yard trip in my future.
 

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Discussion Starter · #11 ·
I think now because she has heat, I have a the CCM grounding problem because the snow actually melted.

I have plenty of DC power from the battery , but nothing but one click when you turn the key. From what I have read its a grounding problem in one of a couple places:
1) Main battery to chassis ground
2) Engine to chassis ground
3) CCM ground to chassis ground
4) or other water in CCM issues

I just wish it wasnt below 15 degrees when I have to do this.
 

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Discussion Starter · #12 ·
I think now because she has heat, I have a the CCM grounding problem because the snow actually melted.

I have plenty of DC power from the battery , but nothing but one click when you turn the key. From what I have read its a grounding problem in one of a couple places:
1) Main battery to chassis ground
2) Engine to chassis ground
3) CCM ground to chassis ground
4) or other water in CCM issues

I just wish it wasnt below 15 degrees when I have to do this.
So I cleaned up some grounds and life is good....almost.

When i flushed the heater core i broke the outlet plastic fitting the hose goes over. by break i mean split along the joint. I couldnt get the hose to go all the way flush so there is like 1/8th of an inch exposed and its leaking. When I get a chance in the next two weeks I an going to pull the hose, clean the fitting, apply some epoxy to the outside and let it cure for 24 hours then put the hose back and see if the coolant leak stops.

Other issues with her:
Liftgate actuator is shot, going to snag one from the scrap yard and replace it. I already took the dead one out.
Horns are shot....I was trying to find the problem from an electrical source...and i couldn't find anything...then i poked my head under the bumper....there might be about 30% of each horn remaining due to rust.


BIGGEST issue, is that it was having its ABS kick on anytime you hit the brakes. So i said fuck it and lets clean the ABS sensors, since every video shows its like a 10 minute job at best. it took over 4 hours to get them out.....Now i have an ABS light on with no codes....some searching has shown that it might have been brake fluid level (which was low) and that was topped off, but still only ABS light and no codes. I also tried the disconnect the battery and pull the fuse, but still light.

I do know that the battery was plugged in when we pulled and cleaned the sensors.....I dunno if this has f$#ked me.
 
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