ShoeBoote

I have a 2005 SL600 biTurbo V12 (R230). When doing diagnostics on my iCarsoft MB 2.0 I get the following code:

P20E1
State:Current
Charge air coolant circuit: Charge air temperature is too high.



I get this code when the vehicle is first started along with when the vehicle is fully warmed up. Not much on this code in these forums other than one response saying to change the intake air temp sensor. This particular question/answer was in the CL-Class (W215) forum so not sure the answer appiles to my situation as my vehicle is a 2005 SL600 (R230):

https://mbworld.org/forums/cl-class-w215/647334-fault-code-p20e1.html

Questions regarding this code for this vehicle class (R230):

1. Is this code something that needs to be remedied right away?
2. What is the possible cause and fix for this?

Thanks in advance.

pmercury

iTrader: (2)

This means your pump is not working or you have air in your circuit

lookup my threads to build a MB Biturbo V12 bleeding tool clone

seven_out

As a consequence of this fault your engine's maximum power output will be diminished, but you can drive with this fault indefinitely.

As mentioned it could be the cooling pump isn't working (blown fuse?) or there is air in the system. It could also be the air temperature sensor, and with regard to that use your iCarsoft to read its value and determine if it is plausible. Star Diagnosis describes procedures for bleeding air, checking the pump, and testing the sensor. If you want help with that reply back.

ShoeBoote

Rod,

Thanks for the reply. I've some questions for you if you don't mind.

First I'll take a look at that fuse. You never know.

Secondly I'll fire up the iCarsoft and see if I can drill down to find the test location where that sensor is mentioned. You mention being able to determine if it's failure is plausible. What reading level would determine that? Some type of over/under voltage it produces maybe? If it needs to be removed, is it the sensor depicted below? (See pics) If so does it easily come out? Looks to me I might need to remove some stuff on the engine to get at it though interestingly enough it doesn't appear to be fastened with screws. Maybe I can get my sausage link fingers in there and pull it out? 🤣 I can't find a removal procedure in the WIS-ASRA though to be fair it's a bear 🐻🐾to navigate through this first time.

You mentioned that Star Diagnosis describes procedures for bleeding air, checking the pump, and testing the sensor. I don't have a Star Diagnosis unit. I'm wondering where I can get one or if there is a substitute for it that can perform the tasks?

I've seen several different procedures for bleeding the system ranging from the procedure mentioned in WIS-ASRA using expensive MeBe tools to using a few fittings, hoses and an empty 2-liter soda bottle. Any leads on what might have worked for you? What type of fluid do you top off with? A water/antifreeze mix? If so what ratios and type of antifreeze?

I guess the high note in this is that I can still drive the vehicle while diagnosing. I guess the silver lining would be less speeding tickets. 🤣


Is this it? If so, I've looked at this sensor online. It doesn't appear to have threading and has two little wings/handles so maybe it's a press in? 🤔

Lots of sensors in view but not the one I think I need to change.

Is that the bugger?

​​​​​​​THANKS!

ShoeBoote

I looked through your threads at that bleeding tool you made. A lot of the links to products you used are dead. What did it cost you to build it?

pmercury

iTrader: (2)

this you mean:
https://mbworld.org/forums/cl-class-...l-version.html

R134a AC Air Condition High Low Side Adjustable Quick Coupler Connector Adapter 15$
1/4 Inch Adapter Converters R12 to R134a Adapter 13$
vacuum pump starts at 55$
vacuum kit 48$
some water filters or a vacuum capable coolant return tank
some hose

I use my compressor tanks as vacuum tanks
using a tank creates a nice vacuum reserve and you don't have wait for the pump to build up
just add some valves and connectors to your compressor to Isolate the compressor pump from the tank

enjoy !

seven_out

I don't own a V-12, nor have I ever worked on one. Pmercury obviously has experience with this, so allow him to guide you.

You have correctly identified the temperature sensor. Intuitively, it should read ambient temperature provided the engine is cool. If it doesn't, then remove its connector and measure the resistance across its two terminals. At 20 degrees Celsius it should measure between 5.8K and 6.4K ohms.

If the sensor checks, my next step would be to see if the pump runs. This is effortless with Star Diagnosis; without it you will need to remove a connector and use a wire or paperclip to jumper some connector sockets. I can help if it comes to that.

To get started with Star Diagnosis you typically begin by purchasing a multiplexer and cables from aliexpress.com.

FranklinG

Absolutely right

here the doc on the coolant + official doc for venting
ONLY use the MB specs blue coolant, this is no a GM engine

ShoeBoote

I haven't removed the sensor yet as the one I ordered hasnt arrived just yet. I am able to see the charge air sensor readings via the my iCarsoft tool. The charge air sensor reads just about the ambient temperture when the engine is cold. On a side note, the coolant and engine temperture sensors both read within one degree C of what the charge air sensor reads so I'm thinking at least from a cold reading standpoint the charge sensor is accurate:

This is the Cold reading before starting. Notice charge air temp is within 1 degree C of engine temp and coolant temp.

The picture below is the one that concerns me. It was taken during a spirited run down the highway so its a little blurry. As you can see the charge air temp seems exceedingly high, almost the same temp as the engine and coolant sensors:


This is the hot reading after a spirited run down the highway. Charge air temp seems exceedingly high - almost as hot as the engine and coolant temps. Im guessing The engine and coolant temps are in the okay range.

I don't have a Star Diagnosis unit. Any help on providing the connections that need to be made to jumper the pump would be appreciated.

I haven't yet sourced the parts to create the vaccum pump to bleed the air out of the charge system just yet. I have however added some MB coolant roughly 50/50 mix via the removable coolant cap. Each time I drive it I let the air out of the little bleeder valves until I get a squirt of the hot coolant. Not much air comes out of the left side. Some but very little comes out the right side. I let the car cool down for several hours and refill the system up to the bottom of the cap. I've done this process 4 times and each time I open the cap after the cool off period I am able to add additional coolant. So far I've added in about 2/3 to 3/4 of a liter in total. The cap doesn't seem to be leaking as I've installed a makeshift overflow reservoir that is tightly attached to the metal overflow tube under the cap. I've gotten a tiny amount of fluid in that overflow. No leaks around the cap either. Just wondering why I'm able to add so much coolant over this time. Is it possible there is that much air in the system?

Thanks

ShoeBoote

Sure would be nice to have that MB vacuum venting equipment but I think I may have to put one together myself or bite the bullet and take it to a dealer or indy mechanic.
Good call on the MB coolant. I guess I'll never be able to get rid of that 20 year old half gallon of Prestone!

ShoeBoote

Thanks for the parts list. I will probably over order all those bits and bobs via Amazon Prime and return what I don't need.

ShoeBoote

Update......

I have added approximately 1.25 liters of coolant mix (45/55) to the air charge cooling system. It was added in 3 or 4 ounce increments over multiple days as air space was created at the fill neck. Now the air charge temp runs between 38C to 70C. Temp goes down for a bit if I race the engine while parked and as I increase speed on the highway.

Is this temp fluctuation an indication the pump is running?

40C to 70C still seems to be a little hot. What is the normal temp I'd see assuming the pump is running, coolant is full and system is properly bled of air?

I'll bleed the system once all my parts arrive. My design is based on pmercury's system as noted in this thread. Right now waiting on the vacuum container. It has a manual pump with the option for a pneumatic hook-up. Not sure if the manual pump will be strong enough to work. Will advise after I try it. Here is the link on Amazon:

https://www.amazon.com/dp/B07N7YV5GN/ref=cm_sw_r_apa_i_gbcTEbZJMNBX5

pmercury

iTrader: (2)

Coolant should be blue and MB specs, not a mix you make
You must find a big enough vacuum resistant tank to create a vacuum reserve and receive a certain amount of coolant out of your system
vacuum pump must be electrical, there is no way you can keep vacuum with a manual pump


https://mybestdealers.com

ShoeBoote

Figured I'd follow up on this post. This is going to be a long one as I’m covering two related repair topics: A failed intercooler pump and low intercooler pump coolant level (air in the system). Most of the repair process was made quite simpler after pmercury hooked me up with diagnostic software (which works on all Mercedes vehicles’ not just this one). If you plan on doing your own work on Mercedes vehicles you should really reach out to him as you’ll save $$$ and most importantly your time! You can do it without the software tools but it’ll take a bit more head scratching.

Conducted the following steps:

1. Intercooler pump changed out for new unit.

2. Bled the air out of the intercooler system.



1. Intercooler pump changed out for new unit.

i. First I needed to determine it was bad. There are two ways to actuate the pump while the car isn’t running. The pump is located behind the front bumper directly below the area where the drivers side headlight meets the grill. One way is to jumper a few connections on one of the fuse blocks. I didn’t do this because I was able to actuate the pump via the diagnostic software (seeing a pattern here?). It is hard to hear if the pump is running as the radiator fan will also usually be running at the same time though you can listen hard for it.

ii. Getting access to the pump is impossible to do without taking the front bumper off the car. Seems like a lot of work but it actually wasn’t that bad. Again, the diagnostic software and its repair steps make it simpler. I took my time so as not to break anything. Putting the bumper back on the car was 4 times quicker than taking it off. Get the car up on jack stands and take the front wheels off. Remove the front most plastic cover underneath the car and the front half of the plastic cover assemblies inside each front wheel well. Go under the car and unplug the connectors for the various lights on the bumper. Remove 4 bolts where the radiator support and top of the grill meet. Remove the long oval shaped lower black grill from the bumper. This took a little finesse with a tool to pry the thing out without damaging the bumper assembly. It also took a little finesse not damaging the outside temperature sensor which is located on the driver’s side of this assembly. The temperature sending unit can be unplugged once you have the oval grill assembly loose. Once that oval shaped grill is removed there are two additional bolts that can be accessed and removed. There are two final bolts that need to be removed: One each from inside each wheel well. Each bolt holds a level type clamp in place that secures the sides of the bumper to the lower front edge of each fender. Once these bolts are out you can swivel the clamps and remove the bumper from the car.

iii. Now you can access the pump. There is one bolt, two hoses and the electrical connector that need to be disconnected. I put a bucket under the pump and disconnected the two hoses. Hardly any coolant came out. I then took out the one bolt and disconnected the electric connector.

iv. The old pump has a rubber grommet around it and a metal plate that holds in in place. Take the grommet off the old pump and put it on your new pump.

v. Reverse the order for reassembly. I waited to reassemble until I bled the system (part 2 below). Your mileage may vary.



Clamp that holds lower front fender to bumper assembly. Bolt holding it together is already removed.



Electrical connectors under front bumper.



Front bumper off car. Easy Peasy.



Intercooler pump location, drivers side front bumper area.



Old pump up top. New pump on bottom. New pump has old pumps rubber grommet in place already. Metal plate with bolt hole in it wraps around the rubber grommet and holds pump in place.



2. Bleeding air out of the system intercooler system. Tried several different ways to extract air and replace with coolant. The ONLY way to get the air out is via vacuum. This means either paying $1,500+ for the MeBe "tool" or making my own. I made my own based on a composite of pmercury's and several others mentioned on this forum. All parts were obtained online and/or locally. They included:

A. Fluid extractor tank to hold coolant as it is vacuumed out. As an added bonus this tank has a manual mode (hand pump). It can also be used to bleed brakes, change oil, etc - B. Screw on connectors (to connect to two valves on top of system) - 7 Pieces Air Conditioning Refrigerant Angled Compact Ball Valve 1/4 Inch SAE for R410A R134A R12 R22 AC HVAC and R410A Adapter 5/16 Inch SAE Female to 1/4 Inch SAE Male Flare for Mini Split System

C. Two small ball bearings (for between "B" above and valves on the top of the system) - Local hardware store

D. Vacuum pump (to draw air/coolant out of the system) -
E. Large funnel which mounts to coolant filler neck (to keep refill coolant in) -
F. 10 feet of plastic hosing, Y fitting and 6 hose clamps - local hardware store.

G. Compressor hose for connecting Vacuum Pump (D) to Fluid extractor tank (A) - I had it on hand. Source it where you can.

H. MeBe coolant and distilled water - Local, online or MeBe dealer.


I hooked things up as follows:

i. Remove cap on system, attach large funnel (E) to filler neck.

ii. Remove two valve covers on Schrader valves at top of system. Carefully place a small ball bearing (C) between valve and valve connector (B). Tighten down valve connector. The reason I needed the ball bearing in between the two was because I was unable to source valve connectors that would actually depress the little valve inside the housing properly once everything was hooked up. The ball bearing is large enough to assist in doing this but small enough to allow air/coolant to pass by. More power to you if you can find valve connectors that work without the ball bearing. I’m sure they are out there. I got tired of ordering stuff and getting the same results.

iii. Connect tubing (F) from each valve to the Y connector (F). Connect third leg of Y connector to tubing for fluid extractor tank (A). Clamp all connections with hose clamps (F).

iv. Connect compressor hose (G) from Fluid extractor tank (A) to Vacuum pump (D).

Procedure once everything is hooked up:

a. Fill the funnel at the top of the system with a fresh 50/50 mix of MeBe coolant and distilled water. You cannot let this reservoir get empty so have extra on hand as you need to run approximately 20 liters through the system to really get all the air out. I didn’t make 20 liters of the mix as the system doesn’t hold near that much. Instead (so as not to be wasteful) I stopped the process several times to empty the fluid that got extracted into the extractor tank back into the fill funnel, in essence cycling the same fluid through several times. If you do the same just be sure to close off any valves that are open before doing that so as not to draw air back into the system via the hoses.

b. Turn on vacuum pump then open the valves up. You'll see air and coolant being sucked out through the valves, down the hoses and into the fluid extractor reservoir. Keep filling funnel at the top of the system so it doesn’t get completely empty otherwise you may draw air back in through the filler neck. Stop the process if necessary to empty the fluid extractor reservoir back into the filling funnel. Continue until you’ve run 20 liters through the setup.


Funnel, Valves, hose and connectors. Note: I ended up using slightly heavier hosing as the thin stuff in the picture tended to collapse uder pressure.



Valves with the small ball bearings.



Fluid extractor, vacuum pump, compressor hse and MeBe coolant.



The setup connected to the car. Vacuum pump is off to the right and not in the picture.



Better view of connection to the car. These upper sections of hose in the picture were replaced with a slightly heavier hose AND hose clamps after this shot was taken. The thinner hose pictured compresses and hose clamps make for a better seal.



Close up view of connection to valves.


Hope this helps.

pmercury

iTrader: (2)

great job !

matk

Very nice write up and great idea on the ball bearings.