No X Sensor!!!

[S350L]

Hi All

After my local MB dealer changed the EGR valve, map sensor and hose, the engine light was still on. They said that the downstream NoX sensor needed changing. There were messages on the dash when the car went in, but when I got it back, the message on the dash said, ADBLUE WARNING, Engine will not start.

I cleared the codes with my reader, and drove the car. I’ve done about 600 miles now and the engine ligh5 has come on, 3 times. The codes are P22a1 & P22ap. I believe these do relate to the NoX sensor, but I’m a little confused as I can drive a 200-300 miles before the the engine light comes on and before Nd codes are stored.

Anyone have any suggestions other than simply changing the NoX sensor?

Thx in advance

 

[skippyjasper]

Add some details on your vehicle: year, miles, model.

 

[S350L]

Thanks

2012 s350 L Bluetec BlueEffiency with 71000 miles under her belt

 

[ernie]

Thanks

2012 s350 L Bluetec BlueEffiency with 71000 miles under her belt

If never changed before, it may well be a NOx sensor problem. It might be worth seeing if MB will make a contribution as these have been modified a few times. You may also find you will need to change both of them as they need to match. All in all, not good news. Mine would have cost me around £1200 but for an extended warranty.

I've just re-read your post....for the sake of £20 they gave you back your car with an empty Adblue tank?

Ernie

 

[S350L]

OK, so the issue has a twist

The AdBlue countdown timer (and engine light) came on and counted down from 500 miles. I plugged my obd reader in and got 3 codes p0800, p1070 & p2ba7. I tried erasing them several times but without success. The countdown continued for a couple of days, down to 78 miles. On Saturday, I booked it in to a Mercedes dealer for tomorrow. Yesterday I got in the car to move it and the countdown time had vanished, the engine light had gone out and there’s no codes when I plugged the reader in again. I drove it for a couple of hundred miles yesterday without a problem . No lights, warnings or codes, however I noticed the ECO ( stop start system) light was changing from green (ready) to orange ( not ready) during my journey. So on the motorway at a steady 70 it would be green for a while then oranage for a while and vice verse.

Any ideas, anyone?


Many thanks in advance