SL55/63/65/R230 AMG: No power going to my IC pump
I noticed the intercooler pump was not flowing water when I took the cap off my split tank. Upon checking, I have no power to my Peirberg 50 pump when the engine is running. It was installed with a resister to keep the pump constantly on. It has run fine for 6 months. I was having a hiccup issue which Jerry suggested a reload of the tune file might fix. Even though it loaded with a message about some "packets" may have been missed, Jerry assures me that as the car started ok the tune would be 100%.
Am I chasing the right things? I did put a voltmeter on the IC pump connector with the engine running and got no volts. Am I right in assuming that if the fuse/relay is ok then the ECU must not be turning on the power to the pump? Cheers again.
Last edited by trabots; Jan 3, 2017 at 10:14 PM. Reason: clarification
I noticed the intercooler pump was not flowing water when I took the cap off my split tank. Upon checking, I have no power to my Peirberg 50 pump when the engine is running. It was installed with a resister to keep the pump constantly on. It has run fine for 6 months. I was having a hiccup issue which Jerry suggested a reload of the tune file might fix. Even though it loaded with a message about some "packets" may have been missed, Jerry assures me that as the car started ok the tune would be 100%.
Am I chasing the right things? I did put a voltmeter on the IC pump connector with the engine running and got no volts. Am I right in assuming that if the fuse/relay is ok then the ECU must not be turning on the power to the pump? Cheers again.




I noticed the intercooler pump was not flowing water when I took the cap off my split tank. Upon checking, I have no power to my Peirberg 50 pump when the engine is running. It was installed with a resister to keep the pump constantly on. It has run fine for 6 months. I was having a hiccup issue which Jerry suggested a reload of the tune file might fix. Even though it loaded with a message about some "packets" may have been missed, Jerry assures me that as the car started ok the tune would be 100%.
Am I chasing the right things? I did put a voltmeter on the IC pump connector with the engine running and got no volts. Am I right in assuming that if the fuse/relay is ok then the ECU must not be turning on the power to the pump? Cheers again.
Below I have attached the factory wiring for M44 (IC Pump) and its fuse location.
There are various strategies for running the pump all of the time (it is possible it has been changed in programming) ... however, worth pointing out, if your pump has been running 100%, it is likely that its relay is no longer controlled by the ECU, but instead circuit 15 (hot when engine is running). I mention this as you may need to inspect this system both backwards and forwards (from the pump backward ... and from the ecu forward) until you know if/how it has been modified.
The connection at the ECU is shown next to the pump in the first attachment (N3/10, connector 4, pin 34). This output is "active low" (provides ground required to turn on pump relay).
on a related note (for those, who are running the CWA-50 or CWA-100), the resistor on the pump was speculatively included on the signal line as a current limiter, but has proven to be optional (as Mercedes wires that pin directly with resistor omitted on newer models that come equipped with peirberg IC pumps of the same design).
Hope this helps,
Chris
Last edited by latemodel21; Jan 4, 2017 at 10:41 AM.
Below I have attached the factory wiring for M44 (IC Pump) and its fuse location.
There are various strategies for running the pump all of the time (it is possible it has been changed in programming) ... however, worth pointing out, if your pump has been running 100%, it is likely that its relay is no longer controlled by the ECU, but instead circuit 15 (hot when engine is running). I mention this as you may need to inspect this system both backwards and forwards (from the pump backward ... and from the ecu forward) until you know if/how it has been modified.
The connection at the ECU is shown next to the pump in the first attachment (N3/10, connector 4, pin 34). This output is "active low" (provides ground required to turn on pump relay).
on a related note (for those, who are running the CWA-50 or CWA-100), the resistor on the pump was speculatively included on the signal line as a current limiter, but has proven to be optional (as Mercedes wires that pin directly with resistor omitted on newer models that come equipped with peirberg IC pumps of the same design).
Hope this helps,
Chris




If you felt like troubleshooting it further, it would tell you a bit to isolate the ecu output (cut the wire) and then monitor it while you turn on the key ... and then when you pass 900 RPM (should toggle from Vbat to 0vdc when active). You could monitor it without clipping the wire, but that will give you confusing results in the odd case where someone has tapped-on an external pull-down circuit (controlled by circuit 15). Feel free to drop me a note if you want to explore this further.
Cheers,
Chris
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IT is hard to tell what the added fuses are doing without tracing them as knowbenz suggested.
The rearward (forward if this were left hand drive) added add-a-fuse is plugged into F21 (circiut 15r, hot in key pos 1,2 and start).
it should be noted that this is plugged-in in such a way that it draws power through F21 rather than directly from the 15r bus ... unfortunately in order to correct this you would have rotate the fuse holder (180 degrees as viewed from above) which would make it hard to close the box up. SO if F21 blows one day (instrument cluster switched power) it may be as a result of the combined load of the cluster AND the added circuit. I have modified/reconfigured these add-on fuse holders for similar locations to have the added fuse draw directly from the power bus (see pic, this one is in an adjacent circuit15 location) but some will argue it is not worth the bother.
The forward add-a-fuse is plugged into F8 (circuit 30 , always hot). This fuse holder is normally vacant, so the orientation of the add-a-fuse is inconsequential.
I just re-read where you mentioned that your pump comes on in position 2, so these added fuses are probably not related to that.
Curios to hear what you find at the other end of the wire(s)
Cheers,
Chris
Last edited by latemodel21; Jan 6, 2017 at 01:07 AM.
I had a 1st look at my box of bits including the cats which were removed. To my amazement the 'primary cats' were totally empty of cat matrix, just empty cans. I presume this is not stock. If so it will confirm the previous owner was chasing performance and had wired the IC pump for key on operation. Why could he not have just run a wire from one of those piggy back fuses which powers on key to the pump? It still however does not explain why a change of tune restored the power to the pump.




I had a 1st look at my box of bits including the cats which were removed. To my amazement the 'primary cats' were totally empty of cat matrix, just empty cans. I presume this is not stock. If so it will confirm the previous owner was chasing performance and had wired the IC pump for key on operation. Why could he not have just run a wire from one of those piggy back fuses which powers on key to the pump? It still however does not explain why a change of tune restored the power to the pump.
One easy thing to check is to remove the factory IC pump fuse ... if the pump still runs this confirms it has been re-wired .... if it does not run, the test is NOT conlusive (as there may be a rewire done that taps into the factory drive circuit ... not unlikely at all).
otherwise, I would go back to my previous post and trace the circuit backwards and forwards to find any deviation.
I have seen cats disintegrate, but more often then not they leave BIG chunks further down (which tend to clog things up) or rotate/shift in their case (which can make a major clog). I have never heard of "dual immaculate disintegration" of cats ... so I would assume it was a performance mod (they should call this the "california tune up" : )
Cheers,
Chris
One easy thing to check is to remove the factory IC pump fuse ... if the pump still runs this confirms it has been re-wired .... if it does not run, the test is NOT conlusive (as there may be a rewire done that taps into the factory drive circuit ... not unlikely at all).
otherwise, I would go back to my previous post and trace the circuit backwards and forwards to find any deviation.
I have seen cats disintegrate, but more often then not they leave BIG chunks further down (which tend to clog things up) or rotate/shift in their case (which can make a major clog). I have never heard of "dual immaculate disintegration" of cats ... so I would assume it was a performance mod (they should call this the "california tune up" : )
Cheers,
Chris




One place to look at for your IC pump investigation is its drive relay. Mounted direct below F51, relay "R" is normally triggered (active low) by the ECU. If someone were to create a work-around, a simple way would have been to remove relay "R" and plug a wire (hot when key is in position 2 and fused at 7.5 amps) into the spot where terminal 87 of the relay was (this is the relay output that is wired directly to the hot side of the IC pump) . Look here for added wiring both on the front and back side.
I have marked up a pic to show where relay R is/was and which pin was terminal 87.
hope that helps,
Chris




sorry for the confusion ...
instead of using F51 and relay "R" like 2003 through 2005,
your car likely uses F60 and relay K60
attached are a couple of pics.
looking at the first pic (wiring diagram) ....
while the fuse (F60) (which goes to K60 pin 8) is hot all the time (circuit 30), it is not clear as to the power that is on pin 6 of the K60 (in turn coming from K40/5). If K60 pin 6 is sourced directly from circuit 15 (hot in position 2 and start) then shorting the relay drive (K60 pin4) to ground would make your pump run anytime you are in key position 2.
so, you can check to see if pin 4 of the K60 connection has be changed so that it goes to ground (instead of to the ECU as it was originally wired) and check to see if pin 6 of the K60 is (or was and still is) tied to circuit 15 (does it read 12vdc in key position 2?).
hope this helps,
Chris
Last edited by latemodel21; Jan 7, 2017 at 10:48 PM.
sorry for the confusion ...
instead of using F51 and relay "R" like 2003 through 2005,
your car likely uses F60 and relay K60
attached are a couple of pics.
looking at the first pic (wiring diagram) ....
while the fuse (F60) (which goes to K60 pin 8) is hot all the time (circuit 30), it is not clear as to the power that is on pin 6 of the K60 (in turn coming from K40/5). If K60 pin 6 is sourced directly from circuit 15 (hot in position 2 and start) then shorting the relay drive (K60 pin4) to ground would make your pump run anytime you are in key position 2.
so, you can check to see if pin 4 of the K60 connection has be changed so that it goes to ground (instead of to the ECU as it was originally wired) and check to see if pin 6 of the K60 is (or was and still is) tied to circuit 15 (does it read 12vdc in key position 2?).
hope this helps,
Chris
As my car is going into the muffler shop to get a custom muffler installed where the secondary cats were, I now want to cut open the empty primary cat cans, install a couple of baffles, weld them back together and re-install them.




As my car is going into the muffler shop to get a custom muffler installed where the secondary cats were, I now want to cut open the empty primary cat cans, install a couple of baffles, weld them back together and re-install them.
The pictures of the rear SAMs I posted earlier in the thread are all from the Mercedes web based Electrical Troubleshooting Manual (ETM), I suspect the first (early) rear sam pic was a non SC R230 (SL500). My rear SAM (pic attached) is more populated and has a relay in the K60 position, but not one above it (guessing they added K60 in 2006 bumping up existing relay one position) which is why your pic did not look foreign to me.
I am confused as to what you are planning on doing with your hollow front cats ... are you planning on reinstalling them to make your car more "inspectable"? if so, wouldn't a nice piece of tubing be a better choice than baffles?
Cheers,
Chris




Cheers,
Chris
sorry for the confusion ...
instead of using F51 and relay "R" like 2003 through 2005,
your car likely uses F60 and relay K60
attached are a couple of pics.
looking at the first pic (wiring diagram) ....
while the fuse (F60) (which goes to K60 pin 8) is hot all the time (circuit 30), it is not clear as to the power that is on pin 6 of the K60 (in turn coming from K40/5). If K60 pin 6 is sourced directly from circuit 15 (hot in position 2 and start) then shorting the relay drive (K60 pin4) to ground would make your pump run anytime you are in key position 2.
so, you can check to see if pin 4 of the K60 connection has be changed so that it goes to ground (instead of to the ECU as it was originally wired) and check to see if pin 6 of the K60 is (or was and still is) tied to circuit 15 (does it read 12vdc in key position 2?).
hope this helps,
Chris
I have an 09 SL65 that I was looking to setup with the IC pump running in key pos 2. The mod was quite simple. The IC pump relay for the 09 does indeed live behind/underneath the passenger seat storage bin as shown in the above pic, but the IC pump relay was the one on top of the vertical stack of the two relays shown in latemodel21's post. The purple/red wire going into the "30" terminal on the top relay was the dead giveaway.
The "#6" input to the relay (from latemodel21's post #15) becomes hot with the key in position 2. Grounding the relay blade (#4 in the same diagram, nearest the front of the car -there's an 8mm screw just underneath the relay area which suits perfectly for the ground) and voila, IC pump runs w/ key in pos 2.
I'll attach pics and start a build thread for my car shortly but this mod helps stay ahead of IAT creep (approx 15-20 deg F reduction in general) and lets the pump run all the time the car is on or the key is in pos 2. Not bad for a 20 minute mod!
Thanks again gents!
Last edited by earl3; Jan 1, 2019 at 03:00 AM.



