C250 W204.303 P054615 Fault relating to EGT Sensor 1, Bank 1

[RedElise]

Had this fault and a few other related faults. Had a quick look with icarsoft, at sensor B19/11. I'm pretty sure this is correct sensor, but please correct me if I'm wrong. The reading first thing in the morning was 352oC, when the car was stone cold and had not been started. I therefore took it to local garage and asked them to check and repair. They have replaced an O2 sensor, which looks to me like a Lambda sensor, rather than a Temperature Sensor. Didn't get a mile from garage and MIL back on.
The sensor they changed looks in approximately the right location ( drivers side, just below the ECU, upstream from Cat). I plugged back in when car was cold, before starting and this time temperature reading 850oC.
Can anyone confirm a few things:

1. Is B19/11 the correct sensor (Exhaust Gas Temperature 1, Bank 1)
2. Does it sound like they have changed correct sensor, as I thought it would have been 2 wire sensor and not 5
3. Correct location

Thanks in advance for any assistance offered.

PS: I'm no mechanic

 

[markjay]

Welcome.

Someone more familiar with the OM 651.911 engine will probably be along shortly.

 

[RedElise]

Thank you Mark. Was a bit confused that I'd asked question in correct area. Newbie and all that

 

[steveq]

I had the same fault code and it was the temp sensor.
It was the one bolted into the exhaust manifold.

You are correct that it has 2 wires.
Here is a photo of one although I bought a genuine MB one.

 

[RedElise]

My suspicions are they have replaced the wrong sensor. I’m going to have a look today, for the correct one.

 

[steveq]

To get at the sensor, you have to take off the air filter box. To do that you have to disconnect the ECU cables and the air supply pipe that goes from the front of the car to the airbox.

 

[RedElise]

To get at the sensor, you have to take off the air filter box. To do that you have to disconnect the ECU cables and the air supply pipe that goes from the front of the car to the airbox.

I read that somewhere before, hence reason I knew roughly it’s location. I’d like to be able to get to termination plug at moment, then I could at least check. But can’t find that either. It will be a typical PTC or NTC sensor, which can be easily tested. Finding it and it’s termination point is my issue

 

[steveq]

The temp of the sensor should match the ambient temp when the car is cold and not running. Like yours, my faulty one was showing very high values even when the car was cold.

I did a write up of the issue and resolution on the 'other side'.

 

[steveq]

I read that somewhere before, hence reason I knew roughly it’s location. I’d like to be able to get to termination plug at moment, then I could at least check. But can’t find that either. It will be a typical PTC or NTC sensor, which can be easily tested. Finding it and it’s termination point is my issue

I doubt if you will be able to find the termination plug without finding the sensor to identify the correct cable.
The sensor is on the left side of the engine and the cable comes around the front of the engine (as do a number of other cables) to the connector on the front right side.
I found that routing the cable and putting it into the connector was trickier than fitting the sensor.

 

[RedElise]

Thank you so much for advice

 

[RedElise]

Thank you so much for advice

Did you disconnect battery before unplugging ECU and did you get any issues when powering back up?

 

[steveq]

The sensor going faulty is a common problem. In fairness, it is being cooked constantly and goes from low/zero degs or below to hundreds of degs in seconds.
When I did mine, I was told that the connector can have a problem but for me the sensor was definitely faulty.

 

[steveq]

I didn't disconnect the battery although, in hindsight, I probably should have done.

 

[RedElise]

I didn't disconnect the battery although, in hindsight, I probably should have done.

The red arrow points to sensor the garage changed, which I think is the wrong one. The yellow arrow points to one I think is correct

 

[steveq]

Hi,

I am pretty sure that it is the yellow one. The photo is almost too close but I think that is the exhaust manifold that it is bolted into -- if so then it is the correct one.

You will need to soak that in penetrating oil as it is pretty welded into the manifold due to all the heating cycles it has been through.

Make a careful note of how the cable is routed as it is difficult to get right.

Best of luck.

Regards,
Steve

 

[NicoB]

Salut,

Sunt destul de sigur că este cel galben. Fotografia este aproape prea aproape, dar cred că acesta este galeria de evacuare în care este înșurubată - dacă da, atunci este cea corectă.

Va trebui să vă înmuiați în ulei penetrant, deoarece este destul de sudat în colector datorită tuturor ciclurilor de încălzire prin care a trecut.

Notați cu atenție modul în care este direcționat cablul, deoarece

Hi,

I am pretty sure that it is the yellow one. The photo is almost too close but I think that is the exhaust manifold that it is bolted into -- if so then it is the correct one.

You will need to soak that in penetrating oil as it is pretty welded into the manifold due to all the heating cycles it has been through.

Make a careful note of how the cable is routed as it is difficult to get right.

Best of luck.

Regards,
Steve

I tried to disassemble it but it is very tight I'm afraid I won't break it. I haven't tried oil