P0050 and P0056 fault codes

[shikkster]

Hi all,
My engine management light keeps coming on. On my OBD reader the errors are:

P0050 H02S Heater Control Circuit Bank 2 Sensor 1
P0056 H02S Heater Control Circuit Bank 2 Sensor 2
P0050 H02S Heater Control Circuit Bank 1 Sensor 1
P0056 H02S Heater Control Circuit Bank 1 Sensor 2

I asked an auto electrician, who asked me if I had been filling up with Morrisons fuel.. I had - so he said to run a couple of tanks of Shell V Power through it and try again. Unfortunately this hasn't sorted it, and every time I start the car back up after clearing the codes the light comes back on within seconds.

I looked at the live outputs for the metrics:
O2S21 stays at 0.03mA even when I rev (assume that this is bank 2 sensor 1?)
OS211 varies around 0.90mA when I rev
O2S12 varies around 0.680V when I rev
O2S11 stays at 0.425V even when I rev

Any thoughts/ideas/suggestions of which direction I should be looking most appreciated

Thanks


Matt

 

[shikkster]

Probably should have mentioned that this is a 2006 E86. The engine management light first started coming on around the time the starter motor went - although I'm not sure that they are related.

 

[enuff_zed]

Probably should have mentioned that this is a 2006 E86. The engine management light first started coming on around the time the starter motor went - although I'm not sure that they are related.

Did you disturb anything else when you changed the starter motor?
Would be odd for all those sensors to fail at the same time?
Anything disconnected?
MAF all fitted correctly?
Any pipes maybe not quite on properly, causing an air leak and affecting the mixture?

Well worth having a very good confidence check all round the engine bay as it sounds likely something was disturbed.

 

[colb]

Odd that all the sensors are all showing heater circuits failed, check the wiring connections at each sensor are clean and connected correctly
Once up to running temp take a look at the live data from each sensor, Banks 1 and 2 (Pre Cat sensors should be producing a wave pattern of voltage as they range up and down the scale. Banks 2 and 3 post Cat sensors don't usually show much activity if they are not picking up unburnt fuel in the exhaust, they look pretty static when viewed in live data.
You should be able to test the heater circit on each sensor by using a voltmeter set to continuity so when you connect to the heater feed wire and an earth you should get a beep from the meter if the internal circuit is intact and capable of working,
Look on Youtube for how to test exhaust sensors for details of how to test them.

 

[shikkster]

Thanks both. It was a local BMW specialist that did the starter motor - they've always been pretty good in the past. One night this week when its not raining I'll double check the pipes and the MAF sensor. I only have bank 1 and 2 as far as I am aware.. I think bank 1 is cylinder 1-3 and bank 2 cylinder 4-6?

Just seen my typo above.. last line should have been:
O2S22 stays at 0.425V even when I rev

So I guess bank 2 not showing much activity isn't a surprise then. I will have to get a voltmeter to do some testing.

Much appreciate the info

 

[shikkster]

Hello,
Just to update what happened here.. I couldn't find anything unconnected etc in the car when I had a look so ended up booking into a different BMW indie in Stockport (and a 3 week wait before they could book me in!)

They found that both Lambda sensors needed replacing.. which they have done and I no longer have an engine management light!

Thanks everyone that took the time to reply


Matt

 

[enuff_zed]

Hello,
Just to update what happened here.. I couldn't find anything unconnected etc in the car when I had a look so ended up booking into a different BMW indie in Stockport (and a 3 week wait before they could book me in!)

They found that both Lambda sensors needed replacing.. which they have done and I no longer have an engine management light!

Thanks everyone that took the time to reply


Matt

Thanks for letting us know.
Either coincidence, or maybe the cheapo fuel did tip them over the edge.