Engine Light and DTC Monitors
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2011 R350 Bluetec
Engine Light and DTC Monitors
I just got a 2011 OM642 BT where the engine light comes on after a couple of cycles with generic code P22A1 on my reader, before i bought I have record of a dealership pulling 11180 according to the tech notes (maybe he meant 111800 which kinda says NOx downtream doesn't like something). They recommended NOx sensor replacement and then go from there....sounds like throw some most likely parts at it and then reassess.
I pulled both NOx sensors and three temp sensors and cleaned them. I also pulled the dosing valve and cleaned the nozzle and port which were caked with crystals. I drove around a few start/stop cycles and watched the monitors go Ready and it seems when the 'exhaust gas sensor' goes ready is when the MIL lights. I've driven around until all monitors go ready but MIL stays on - maybe not enough start/stops. However, if I clear the MIL/error code it comes back on after a couple of cycles on its way to making the monitor ready. It does complete a regen and all monitors go ready but MIL still on.
Anyone had this problem? Is there an O2 sensor further up before the DPF that needs attention? Is it an intermittent NOx sensor? MIL doesn't come on right away but only after some monitors check.
Thanks
I pulled both NOx sensors and three temp sensors and cleaned them. I also pulled the dosing valve and cleaned the nozzle and port which were caked with crystals. I drove around a few start/stop cycles and watched the monitors go Ready and it seems when the 'exhaust gas sensor' goes ready is when the MIL lights. I've driven around until all monitors go ready but MIL stays on - maybe not enough start/stops. However, if I clear the MIL/error code it comes back on after a couple of cycles on its way to making the monitor ready. It does complete a regen and all monitors go ready but MIL still on.
Anyone had this problem? Is there an O2 sensor further up before the DPF that needs attention? Is it an intermittent NOx sensor? MIL doesn't come on right away but only after some monitors check.
Thanks
