O2 sensor heater DTC

[x Spades x]

How?
I need the data in my previous suggestion to help.

*Update*
So the O2 sensor wiring for bothe pre/post cats are fine;however, I stumbled upon a wire that IS damaged (pictured).

This looks to be the EGT wire that has been severed. Would this be a reason for my catalyst errors (178/179), and lean codes (before Hassan gave me a base tune that turned the rears off? Could this stop the O2 heaters from coming on?

[sapote]

*Update*
So the O2 sensor wiring for bothe pre/post cats are fine;

visual inspection is not enough. You need to measure the voltage as I suggested.

[x Spades x]

visual inspection is not enough. You need to measure the voltage as I suggested.

So i measured the ohms as follows:

Brand new (1 week old - Bosch)
Bank 1 Pre - 3.1ohms
Bank 2 Pre - 3.4ohms

Used
Bank 1 Post - 3.7ohms
Bank 2 Post - 3.6ohms

[eacmen]

So i measured the ohms as follows:

Brand new (1 week old - Bosch)
Bank 1 Pre - 3.1ohms
Bank 2 Pre - 3.4ohms

Used
Bank 1 Post - 3.7ohms
Bank 2 Post - 3.6ohms

I'm not sure what ohms of the sensor is going to tell us.

Need DC voltage on the ecu side on the pins sapote described above to see if the ECU is even commanding the heaters on or not.

[x Spades x]

I'm not sure what ohms of the sensor is going to tell us.

Need DC voltage on the ecu side on the pins sapote described above to see if the ECU is even commanding the heaters on or not.

Aaaah ok, apologies. I know what is requested now. I'm only it, thanks!!!

[eacmen]

Aaaah ok, apologies. I know what is requested now. I'm only it, thanks!!!

Just make sure to measure with engine running

[bmwfnatic]

I'm not sure what ohms of the sensor is going to tell us.

Need DC voltage on the ecu side on the pins sapote described above to see if the ECU is even commanding the heaters on or not.

It seems to be the method the DME uses to determine if the heaters are working or not, it wants to see between 4.5 and 18.6 Ohms.

[x Spades x]

It seems to be the method the DME uses to determine if the heaters are working or not, it wants to see between 4.5 and 18.6 Ohms.

So are you saying mine are too low?

[sapote]

So i measured the ohms as follows:

Brand new (1 week old - Bosch)
Bank 1 Pre - 3.1ohms
Bank 2 Pre - 3.4ohms

Used
Bank 1 Post - 3.7ohms
Bank 2 Post - 3.6ohms

This shows all the heaters in the O2 sensors are good.
But you need to measure the voltage on the same two wires so we can tell if the DME commanded the heater ON or not, with engine running. Note: you might see 0v, or 12v constant, or it is switching from 12v to 0v alternatively, depending on the temperature of the heated sensor that the DME modulates the 12v (switching pwm) to control the heat.

[x Spades x]

This shows all the heaters in the O2 sensors are good.
But you need to measure the voltage on the same two wires so we can tell if the DME commanded the heater ON or not, with engine running. Note: you might see 0v, or 12v constant, or it is switching from 12v to 0v alternatively, depending on the temperature of the heated sensor that the DME modulates the 12v (switching pwm) to control the heat.

ok so i checked what you requested, while engine was at full operating temp. All results were the same for Pre and Post O2 sensors:

Both Pre O2s
Red/White wire: 13.5v
Brown wire: Fluctuated between 0.13 - 0.18v

Both Post O2s
Red/White wire: 13.5v
Brown wire: Fluctuated between 0.13 - 0.19v


So the ground isn't even close to the 0v and 12v switching. They literally just fluctuated up and down in that small range. What does that mean?

[sapote]

ok so i checked what you requested, while engine was at full operating temp. All results were the same for Pre and Post O2 sensors:

Both Pre O2s
Red/White wire: 13.5v
Brown wire: Fluctuated between 0.13 - 0.18v

Both Post O2s
Red/White wire: 13.5v
Brown wire: Fluctuated between 0.13 - 0.19v


So the ground isn't even close to the 0v and 12v switching. They literally just fluctuated up and down in that small range. What does that mean?

The brown wires are not 13.5v and this means the DME is working.
Don't expect to see a perfect 0v as there is always some voltage drop on connection and chips. I expect that the DME should be modulating the brown wires (pwm switching) to control the current thru the heater instead of just 0.19v as this would cause the heaters to be at max hot all the time. The switching you saw from 0.13v to 0.19v could be that your DVM is not able to display the fast switching of the pwm signal. I'm curious what you will see when switch the DVM from DC voltage to AC voltage measurement and measure the voltage again, or if your DVM has the frequency mode then measure the frequency at the brown wires.

Anyway, with brown wires are near 0v, the heaters should be hot so I wonder why the error codes popped up.

Where exactly on the wires did you do the measurement? Can you measure on the sensor wires side?

[sapote]

Did you use inpa to look at the o2 sensor heaters status to confirm it match with the error codes?

Can you do a log using OBDFusion to collect the data for the 4 sensors, engine temperature? Do this for cold engine and hot engine idling. The log can tell how well the sensors working (if the heaters don't work then I expect to see the lazy switching precat sensors).

[x Spades x]

The brown wires are not 13.5v and this means the DME is working.
Don't expect to see a perfect 0v as there is always some voltage drop on connection and chips. I expect that the DME should be modulating the brown wires (pwm switching) to control the current thru the heater instead of just 0.19v as this would cause the heaters to be at max hot all the time. The switching you saw from 0.13v to 0.19v could be that your DVM is not able to display the fast switching of the pwm signal. I'm curious what you will see when switch the DVM from DC voltage to AC voltage measurement and measure the voltage again, or if your DVM has the frequency mode then measure the frequency at the brown wires.

Anyway, with brown wires are near 0v, the heaters should be hot so I wonder why the error codes popped up.

Where exactly on the wires did you do the measurement? Can you measure on the sensor wires side?

I haven't gotten an error for heater. The errors I'm getting are Too Rich/Lean (both banks), Trims (both banks), Catalyst (both banks), and occasional Under threshold. If I put on a base tune with nothing turned off, I'd get about 7 errors (mix of the above)... but throughout all of that, O2s would ready up and heater would stay incomplete for 500 miles.

[x Spades x]

Did you use inpa to look at the o2 sensor heaters status to confirm it match with the error codes?

Can you do a log using OBDFusion to collect the data for the 4 sensors, engine temperature? Do this for cold engine and hot engine idling. The log can tell how well the sensors working (if the heaters don't work then I expect to see the lazy switching precat sensors).

does engine temp have anything to do with it? I just installed the efan and have trouble getting it to play nice with the system. Engine (and oil) seem to both be below operating temp (i made a separate thread about that).

I viewed sensor activity at idle abd posted the vid a few posts back. I don't remember if I checked for the heaters being on, so I can do that now

[lemoose]

How did you confirm the ECU box fuse was ok?