Persistent 12444 fault and rough running

[jeffbebe]

I've been trying to solve a persistent issue for the best part of 6 months now to no avail. The only fault code I can glean (from stomp test as my diagnostics don't work currently) is 1222 - lean/rich on bank 1 - which comes with the following symptoms:

• Intermittent misfire - but usually goes within a few mins of driving if it's there on start up. Sometimes comes back seemingly randomly (but usually only if the ignition is turned off then on again)
• Unburnt fuel smell (sometimes with the misfire, sometimes not) - particularly on start up but not always
• Surging idle on start up - hot and cold but usually worse when cold - goes as soon as you rev.

I have new Bosch O2 sensors, I've recently replaced the entire ignition system. No vac leaks and injectors were serviced at the same time as top end recondition about 2 years ago (less than 10K kms). New batteries. Replaced the fusible links. No fuel leaks from the pump seal and plugs look good and clean. Swapped the fuel tank breather valves, MAFs, DKs, etc but fault stays on bank 1.

Realised today I haven't tried swapping the DMEs which I'll do tomorrow but would appreciate any other bright ideas... I'm at a total loss.

I did notice a bit of oxidisation on one of the fuel tank breather valve plugs - not enough to concern me ordinarily, but I'm clutching at straws at the moment. The valves are next to each other - one above and one below - can anyone confirm which is for bank 1, top or bottom?

Also, since switching the fuel tank breather valves the CEL goes on each time the misfiring occurs and turns off if you rev a little harder. Fault has not switched sides though??

PS, sorry about the typo in the thread title!

[MIKYZZ4]

That code translates to either,
P1244 – Diagnostic Module Tank Leakage Pump Control Circuit Signal Low (BMW)
or Fuel Pump Emergency Shutoff

[8eights]

Could ba a short at battery to ground , Check that all is tightly grounded, Also check your alternator.

[jeffbebe]

That code translates to either,
P1244 – Diagnostic Module Tank Leakage Pump Control Circuit Signal Low (BMW)
or Fuel Pump Emergency Shutoff

Sorry, it was a typo. 1222 is the code.

- - - Updated - - -

Could ba a short at battery to ground , Check that all is tightly grounded, Also check your alternator.

Should have added I replaced the ground strap but are you referring to individual grounds at each battery? Don’t know much about alternators. Battery seems to charge okay when driving but how else can I confirm if alternator is operating as it should?

[8eights]

1222-------Lambda Control #1 Might not be plugged in good.

[jeffbebe]

1222-------Lambda Control #1 Might not be plugged in good.

New Bosch sensors and issue presented before replacing as well as after, so 100% sure the sensor is not at fault.

[cartoonz]

You certain the O2 sensors are plugged into the correct plugs?

[jeffbebe]

You certain the O2 sensors are plugged into the correct plugs?

Yep, haha! It would run rough all the time if they were!

[JDP530]

Did you use BMW wires and sensors when you replaced those parts?

[Timm]

The code refers to a lack of closed-loop control, not a fault with the sensor - this means that there is an air/fuel mixture problem and as it is intermittent then that usually means ignition faults. Having a look at adaptations with diagnostics will give you a better idea.....

[jeffbebe]

The code refers to a lack of closed-loop control, not a fault with the sensor - this means that there is an air/fuel mixture problem and as it is intermittent then that usually means ignition faults. Having a look at adaptations with diagnostics will give you a better idea.....

Agreed. Unfortunately, I still haven’t managed to get diagnostics working (I have access to the correct diagnostics setup so it’s definitely the car not the diagnostics equipment). Have replaced GM capacitors, and pulled various other modules in an effort to identify which is stopping the diagnostics from functioning but to no avail... so far. Will keep (un)plugging away at that as old school methods to find the ignition fault have failed me so far.

- - - Updated - - -

Did you use BMW wires and sensors when you replaced those parts?

Yes, all OEM.

[spikec]

This was a tough one that I plowed through several years ago, but I only have an 8-cyl so it 's probably something different with your 12. We replaced the O2's a couple times, tested for vac leaks, fuel pressure, etc numerous times...you name it, we tried it. I ended up just saying f'it, got a new engine chip from DUDMD, and now make other arrangements for my emissions test every year. Haven't had a problem since and the engine runs like a top :-)

[jeffbebe]

This was a tough one that I plowed through several years ago, but I only have an 8-cyl so it 's probably something different with your 12. We replaced the O2's a couple times, tested for vac leaks, fuel pressure, etc numerous times...you name it, we tried it. I ended up just saying f'it, got a new engine chip from DUDMD, and now make other arrangements for my emissions test every year. Haven't had a problem since and the engine runs like a top :-)

Interesting. I'll try swapping the DMEs this weekend and see if the fault swaps banks. If so, I have a couple of spare chipsets I can try.

[spikec]

Good luck Jeff, let us know how it turns out. There's just strange things that happen with these beasts, be it 4-short or regular flavor!