Lambda replaced, still dodgy AFR readings on N54 335i

[threetirtyfive]

Hi guys
my car was throwing up errors on bank 1 sensor 1 and bank 1 sensor 2 lambda sensors. After much hassle I managed to use a flexible wrench with a flexible extension bar to an O2 socket to remove the sensor from the top of the engine bay and replace it, definitely bank 1 - as it was nearest to the front of the car, black lead, however, after replacement, and resetting the service light, it promptly came back and logging in MHD shows the same odd readings from this lambda sensor-
http://datazap.me/u/threetirtyfive/3...g=0&data=17-23

now the guy who sold me the car said that the modified program it was running was causing the lambda sensors in bank 1 to report faulty, BS I thought so I set about replacing them. Admittedly I only replaced b1s1 as I was more concerned with the AFR than the function of the cat, but perhaps his story wasn't wrong and it's indeed the program, anyone ever heard of this before?
I had the fuelling checked whilst it was on dyno and it was fine, not too lean or rich, so I guess it's all being controlled off bank 2 right now. Also no idling issues, no hesitation, car makes good power.

[jt0407]

Bank 1 wideband is not working. Did you damage the sensor, when trying to install it? You can break the heating element inside of the sensor, very easily..

[threetirtyfive]

I seriously doubt I damaged it as I inserted it (and tightened initially) by hand. Are there any other causes- such as wiring fault to ECU / modified program running in ECU?

[Sered]

Another thing to check is the condition of the secondaries. I noticed before I disabled my secondaries that they affected the AFR_1 and AFR_2 signal in a similar manner to how you describe (and I was getting a failure message once in a while for one of my secondaries). Once I disabled them, the problem went away (also replaced both primaries as they were dead).

[threetirtyfive]

Another thing to check is the condition of the secondaries. I noticed before I disabled my secondaries that they affected the AFR_1 and AFR_2 signal in a similar manner to how you describe (and I was getting a failure message once in a while for one of my secondaries). Once I disabled them, the problem went away (also replaced both primaries as they were dead).

Great OK thanks. I do have a new oem bank 1 sensor 2 so will try that and see if it affects the afr sensor. Odd thing is there is some signal from bank 1 sensor 1 as shown by the mhd log but it hovers around 15.

[jt0407]

Great OK thanks. I do have a new oem bank 1 sensor 2 so will try that and see if it affects the afr sensor. Odd thing is there is some signal from bank 1 sensor 1 as shown by the mhd log but it hovers around 15.

because it's dead. Mine showed the same AFR as yours, when mine went out.

[threetirtyfive]

@jt0407 - I guess I should swap the bank 2 sensor 1 connector with bank 1 sensor 1 - this will tell me for definite if it's the sensor or wiring, and do anther log - can't see it doing any harm? As I say it's a brand new sensor I just fitted, readings are almost identical to the old presumably broken one.

[jt0407]

What codes are you getting?

[threetirtyfive]

I have p0030 and p0036.

[jt0407]

Get MHD , so you can properly read codes.

[threetirtyfive]

I have it already, on that it gives 2c9c,lambda probe heating in front of cat input signal, 2c9e after cat, 2ef7 characteristic diagram thermostat controls

[jt0407]

2c9c is a bad 02 and the heating element is damaged. I had the same code.

[threetirtyfive]

I just replaced bank 1 sensor 2 and STILL have the faulty heater fault on both. What other causes are there, where are the wires if I open the dme box and look for damage?

[threetirtyfive]

Just to add, I did reset the check light but it came back after ten min

[jt0407]

May need to check your DME board, for any fried resistors or capacitors. It's a long shot,though.

[threetirtyfive]

I only want to lift the case from the box with the dme in not actually dismantle the dme itself looking for component damage. Do you know which wires enter the box that relate to the o2 sensors?

[windymissile]

I am now looking for resistor damage in the dme too.

The heater elements are fused. Have you checked the 30A fuses in the glove box?

[threetirtyfive]

I don't know which fuse it is, the photo in bimmer boost in another post show a different fuse box. My e92 is different, not sure which fuse can you tell me? Are there different fuses for bank 1 and bank 2? Because bank 2 work fine.

[windymissile]

There should be a fuse map in your glovebox. The ECU has about 10 fuses. Its one the 30A ones. I believe the 2 banks are fused separately.
WM

[threetirtyfive]

I checked the under hood (bonnet) fuses last night, all passed continuity test so none are blown from the black cube fuse holder in the DME box, where I understand on the coupe the fuses are. Still no closer to solving the issue unfortunately. Is it possible to test -from- the connector in the car loom that the signals are correct for the 02 sensor? (rather than testing the 02 sensor itself)

[CKI@Motiv]

-Your in OL fueling so yes the car will run fine its programmed to do so.
-I would remove both connectors on the DME and make sure none of the pins are pushed. Sometimes after installing/removing a piggyback the connector wont mate correctly and it pushes the pin back just enough to not get a good connection.
-Your e92 has a single fuse for all 4 heaters. I forgot which 1 it was but if it was blown all 4 heater faults would be present.
-in INPA go to adaptations then go to adaptations 1 and clear anything that says lambda, or NOX. Then make sure you hit <shift> F6 (or7) for learn variance. Back out of that menu go to adaptations 2 then select Clear ALL. Then do a DME reset. Easiest way is while your in INPA go to sleep mode then DME reset. Shut the ign off then start the car
-All else fails buy another sensor. If the heater isnt working its most likely done anyways. Damage to the outside of the housing can cause it to short and fail internally.

[BostonBeemah]

Easiest way is while your in INPA go to sleep mode then DME reset. Shut the ign off then start the car

Just to clarify do you mean put the computer into sleep mode, like shut the lid, or is there a sleep mode option in INPA I've never seen before for the DME??

[CKI@Motiv]

Just to clarify do you mean put the computer into sleep mode, like shut the lid, or is there a sleep mode option in INPA I've never seen before for the DME??

<shift> F10 is the DME sleep mode option. You'll see it on the main page for the N54 sub menu. once you click that itll have choices for reset all, reset DME only, etc. All you need is Reset DME only

[BostonBeemah]

<shift> F10 is the DME sleep mode option. You'll see it on the main page for the N54 sub menu. once you click that itll have choices for reset all, reset DME only, etc. All you need is Reset DME only

No way, all this time have never seen that. Hah must be half blind or something lol thanks!

[threetirtyfive]

This is great advice thanks guys, lots more to try out, I haven't used INPA other than successfully getting it to connect so far. (Used NCS expert for coding, that's about it).