O2 sensor connections

[Bmwe5320023.0]

That makes sense. Both sensors on Bank 1 (pre and post cat) are showing an error and have the same voltage. Even though they're both connected.
I guess I can try connecting spare o2 sensors to those plugs/connectors and see if I get any readings from ambient air. If not, the wire could be damaged somewhere behind the engine

[andrewwynn]

Yep that's the idea. It's not difficult to trace the wires into the e-box where you can determine continuity. I did when I was trying to solve an O2 sensor heater issue that wouldn't go away.

Come to think of it, also how to determine which wire for which sensor. TIS will have the pinout.

[Bmwe5320023.0]

I tried disconnecting sensor 1 and 2 on Bank 1 and connecting spare o2 sensors to those connectors without any luck.
The voltage stays the same and the errors come back right away.
I tried tracing wires for bank 1 but they go behind the engine where I can't reach.
Those wires must be damaged somewhere but are they even replaceable or are they part of engine harness?

[andrewwynn]

It's in the engine harness but you can find which wire isn't working and run your own wires parallel but I would start by finding the pinout from the DME and test continuity on each sensor wire.

[Bmwe5320023.0]

What a shame they closed down https://www.newtis.info/

I found DME MS43 pinout though
https://www.ms4x.net/index.php?title...ns_MS43_Pinout

And o2 connectors


I guess the connectors i have to check for continuity with DME are X62101 and X62102
The only problem I can't seem to find the pintout for those connectors who know which DME pins to test for continuity with wich O2 terminals (since there are 4 terminals per O2 connector).

For example pins on DME for bank 1 sensor 1

1 Output [PWM] O2 Sensor Heater Pre-Cat Bank 1 Heated O2 Sensor Pre-Cat Bank 1 B62101
14 Input [0-5V] Signal O2 Sensor Pre-Cat Bank 1 Heated O2 Sensor Pre-Cat Bank 1 B62101
20 Ground O2 Sensor Pre-Cat Bank 1 Heated O2 Sensor Pre-Cat Bank 1 B62101

Now what do they correspond to on the oxygen connector?

[Bmwe5320023.0]

After much pain I think I figured it out, at least for sensor 1 bank 1.

Pin 3 of the O2 connector goes to pin 20 of the DME (20 M M_LSV1 Signal ground Oxygen sensor 1 (in front of catalytic converter))
20 Ground O2 Sensor Pre-Cat Bank 1
Black wire (so looks like this wire is simply ground and is not critical, since the O2 sensor is already grounded by being screwed into the cat.

Pin 4 of O2 connector goes to pin 14 of DME E A_LSV1 Sensor signal Oxygen sensor 1 (in front of catalytic converter)
14 Input [0-5V] Signal O2 Sensor Pre-Cat Bank 1
This wire is yellow. Looks like this is where DME is receiving the signal from O2 sensor, which will produce volts depending on temperature. The only think not clear to me is I thought O2 sensor provides between 0 and 1 volts, so why does this day 0-5V?

Pin 2 of O2 connector goes to pin 1 on the DME
1 M T_LHV1 Oxygen sensor heating ground
1 Output [PWM] O2 Sensor Heater Pre-Cat Bank 1
Brown wire
Something to do with pulse width modulation. I think it does something to the voltage.

Last is pin 1 on O2 connector and it goes to pin 8 of the DME fusebox, which is Voltage supply for engine electrical system, fuse 4, 30 amp
Red and white wire
So I figure this is the voltage from O2 sensor to DME, passing through that fusebox?

I guess I can start by checking fuse 4 and then checking resistance between DME connector pins 1, 14, 20 and O2 connector.

[andrewwynn]

The pwm is how the heater runs lower than full power. They are always full power or close eg 97% whenever I watch realtime

[Bmwe5320023.0]

I was able to trace all sensors finally, back to where they belonged. Used a multimeter to find the right O2 connector for the corresponding pin on the DME. Marked them with a marker time lol.
They were all messed up, pre and post.
No more active errors, just 3 shadow errors with TEG_DOWN and TEG_UP Inpa codes.

I heard O2 shadow errors don't mean anything and they won't go away. Saw another post with the same issue.

[andrewwynn]

Not sure what shadow error means. Like a pending error that never posts?

[RocketyMan]

Originally Posted by Bmwe5320023.0

I was able to trace all sensors finally, back to where they belonged. Used a multimeter to find the right O2 connector for the corresponding pin on the DME. Marked them with a marker time lol.
They were all messed up, pre and post.
No more active errors, just 3 shadow errors with TEG_DOWN and TEG_UP Inpa codes.

I heard O2 shadow errors don't mean anything and they won't go away. Saw another post with the same issue.

I get these shadow errors ALL the time because I changed my O2 sensors to NTKs instead of the OE BOSCH ones. Such a pain in the arse. Hindsight is 20/20, but I wish I knew this before hand and just bought the BOSCH O2 sensors.

But yeah, the shadow codes are the ones that pend but never erase. This is most likely due to the resistance of the heater being different from each MFG. What a pain...