Logans33

I hosed my engine down last weekend to clean it but now the car is in Limp Mode with a P2037 DTC.
I used my iCarsoft MB II to clear the code but it comes right back and the car is still in Limp Mode.
Does anyone know where the Reductant Air Injection Sensor is located and it's associated wiring? Also there is a slight "whistling" sound now. Apparently I have shorted this sensor?

wallyp

First - Mercedes did a pretty poor job of sealing all of the sensors, connections and equipment in the engine compartment. It would never occur to a trained Mercedes technician to wash the engine with a water hose, and it never occurred to Mercedes that an owner would do so. We have seen repeated reports of problems caused by water damage.

Second - define "Limp Mode". Exactly what is the car doing/not doing?

The Reductant Air Injection Sensor is used on Diesel engines as part of the system to inject a "reductant", which is usually "DEF fluid", to help with the Diesel emissions. I have never heard of a gasoline engine having such a system.

DTC P2037 is not one of the Federally-required OBD-II codes that are the same for all vehicles, but is one of the optional codes that are defined by the vehicle manufacturer for their own purposes. Apparently Mercedes Benz uses that code for quite a few very different conditions on different vehicles. DAS would tell you what that code means on your particular vehicle - your code reader doesn't appear to be capable of doing that. Here is a list from one of the diagnostic web sites giving the various meanings for the code on various Mercedes vehicles.

P2037 check radiator shutter/engine mount.Engine mount circuit open
P2037 check radiator shutter/engine mount.Engine mount regulator fault (via ground key)
P2037 check radiator shutter/engine mount.Engine mount short to ground
P2037 check radiator shutter/engine mount.Radiator shutter circuit open
P2037 check radiator shutter/engine mount.Radiator shutter regulator fault (via ground key).
P2037 check radiator shutter/engine mount.Radiator shutter short to ground
P2037 No or incorrect CAN message from control unit N15/3 (ETC control module)(P0600)
P2037 no signal or error signal from N15/3 (EGS controller) controller BUS (P0600)
P2037-001 B4/3 (fuel tank pressure sensor),overload short [P0452]
P2037-002 B4/3 (fuel tank pressure sensor),positive short/wire open [P0453]
P2037-004 B4/3 (fuel tank pressure sensor),signal reliability malfunction/fuel tank cover lose.[P0451]
P2037-008 B4/3 (fuel tank pressure sensor),signal reliability malfunction [P0451]

I would suspect that the ones in bold might be a good place to start - if we assume that the code reader actually saw a DTC P2037...

Get a four-foot piece of 3/8" or so of flexible rubber or plastic tubing. Stick one end in your best ear, and use the other end to locate the source of the whistling noise, and see if you have a broken or disconnected line or other leak source. Be very careful to stay away from moving or hot parts.

Logans33

Thanks for the info on the P2037.
I am going to work on it tomorrow until I resolve it even if it takes all day and my wife starts fussing!!!....LOL
The radiator faults sounds closer to being the cause because I distinctly remember the hose being in that area w3hen I started. I basically started at the radiator area, did a quick spray of the top (The MB plastic cover), and that was it.

Concerning the "Limp Mode"
Once I wiped the car down, I took it for a "Dry Off" run to dry the car off and it wouldn't change gears at all.
It starts in 2nd and stays in 2nd.
I have disconnected the ECU and the TCM (Transmission Control Module) in an effort to delete any possible faults but nothing changed.
I used my iCarsoft MB II diagnostic tool to read the codes and that's where I got the P2037.
There are no other codes present in the module.
I tried to connect to the TCM but get an error message stating "Failure in connecting to ECU"
and it doesn't connect at all to the TCM.
I was told that my particular iCarsoft MB II would connect to the TCM to reset it and take it out of "Limp Mode" only to findf out that it doesnt.
I even upgraded the software on the MB II to the latest version but still nothing.
When I use the "Automatic" mode on the tool which detects all modules that should be available to the tool, the TCM is listed as one that should be available.
It comes up in the list, but does not connect to it.

I really think if I could get connected to the TCM my "Limp Mode" could be changed to normal operation.

Any advice, instruction or help in addressing this would be greatly appreciated..

wallyp

I know virtually nothing about the iCarsoft, so no comments there.

You don't have radiator shutters or wired engine mounts, so I seriously doubt that your problems are related to those.

A common problem is that the electrical connector on the back of the transmission for the TCM leaks ATF, which wicks up the wire harness into the TCM and causes problems. It might or might not fix the problem, but this procedure is almost free, and easy to do.
Pull the TCM out of the right front fuse/relay/SAM unit. Pry the box open carefully - you can get it open without breaking anything. Wash the electronics thoroughly with brake cleaner or contact cleaner let it dry and reinstall. See if that helps - if this does help, no reset or code clearance is usually necessary.

If not, you may be back to water damage...

Logans33

I've already pulled the TCM which was right beside the SAM and ECU in the passenger side front under the hood.
it looked to be clear and debris free but I cleaned it anyway by separating it from the plastic housing and using contact cleaner and canned air.
Nothing
My next objective is to trace the harness back to the transmission where it connects (which I assume is under the car somewhere) and see if that connection is good and clean.
If it is then it seems I'm stuck with having to get a new TCM or a used one with the same part number.
I've searched everywhere on the net to find out how to get into the TCM to reset it but have found nothing.

wallyp

The 13-pin connector is at the left rear of the transmission.The connector in the transmission (which is the part which sometimes leaks) is easily replaced (I don't suspect that of being your problem), and the last one that I bought was less than $15 at the Dodge dealership (Sprinter van uses the same transmission). There is one small central screw - which can be difficult to get in correctly.

I would expect DAS to clear the code.

I doubt that this will cure your problem - but it is a transmission "reset", and it is easy, fast and free...

osum

The Whistling noise that you are hearing is the intake manifold hose witch has potentially broken witch is causing the code. To repair the issue I recommend to carefully place a stent or larger hose over the existing one. Be very delicate and extremely careful when attempting the repair. I am speaking from experience. I was able to fabricate a fix if you happen to break the hose off at the bottom of the intake manifold.

Good Luck
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