05 E55, no 12v at fuel pump, new pump relay and fuse is fine
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1999 C43 AMG, 2005 E55 Wagon
05 E55, no 12v at fuel pump, new pump relay and fuse is fine
My 05 E55 will crank but won't start. Like an idiot I assumed it was the famous CPS. Replaced CPS. No change. With key on, I checked fuel pressure at rail and it's bone dry. Replaced fuel pump relay, or at least I think. No change. Even the dealer wasn't sure which relay was the fuel pump relay in the E55 wagon. So I used the new relay to replace all similar relays one at a time and it never fixed it. Checked fuel pump fuse, 20A, it's fine. Replaced it anyway, no change.
So I remove cover to fuel pumps and check for 12v across all 4 lugs at the fuel pump connector. All of them read 0v.
I'm at at my wit's end. Help?
So I remove cover to fuel pumps and check for 12v across all 4 lugs at the fuel pump connector. All of them read 0v.
I'm at at my wit's end. Help?
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'99 and '05 E55 AMG
"E55 fuel pump relay and fuse maintenance". Schematic in that thread. Advanced search upper right. My user name.
Fuel pumps fuse is 30 amp. E55 does *not* pull fuel pumps relay signal from rear SAM; the relay is triggered by a direct connection to the Motor Electronics. Different wiring harness than non-AMGs.
IIRC, the E55 relay in the rear SAM is for the intercooler pump and does use a 20-amp fuse. In the non-AMG that is the fuel pump relay. PelicanParts has a DIY with my input on the difference.
Fuel pumps fuse is 30 amp. E55 does *not* pull fuel pumps relay signal from rear SAM; the relay is triggered by a direct connection to the Motor Electronics. Different wiring harness than non-AMGs.
IIRC, the E55 relay in the rear SAM is for the intercooler pump and does use a 20-amp fuse. In the non-AMG that is the fuel pump relay. PelicanParts has a DIY with my input on the difference.
Last edited by bbirdwell; Jun 23, 2023 at 11:41 PM.
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From: America
1999 C43 AMG, 2005 E55 Wagon
It's a 55 estate, which the diagrams are hard to tell the difference. The dealer indicated the fuel pump relay and fuse are in the rear left and both are good. However the dealer wasn't even able to confirm which relay was the fuel pump relay. But their system did display a relay part number for my car and sold it to me. I replaced all 3 identical relays in rear and it made no difference. The fuse is 20a and in getting 12v there.
Thread Starter
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Joined: Mar 2005
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From: America
1999 C43 AMG, 2005 E55 Wagon
"E55 fuel pump relay and fuse maintenance". Schematic in that thread. Advanced search upper right. My user name.
Fuel pumps fuse is 30 amp. E55 does *not* pull fuel pumps relay signal from rear SAM; the relay is triggered by a direct connection to the Motor Electronics. Different wiring harness than non-AMGs.
IIRC, the E55 relay in the rear SAM is for the intercooler pump and does use a 20-amp fuse. In the non-AMG that is the fuel pump relay. PelicanParts has a DIY with my input on the difference.
Fuel pumps fuse is 30 amp. E55 does *not* pull fuel pumps relay signal from rear SAM; the relay is triggered by a direct connection to the Motor Electronics. Different wiring harness than non-AMGs.
IIRC, the E55 relay in the rear SAM is for the intercooler pump and does use a 20-amp fuse. In the non-AMG that is the fuel pump relay. PelicanParts has a DIY with my input on the difference.
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2002 S430 and 2005 E55 AMG
I’m not sure about the wagon. But I know that the E55 and E63 fuel pump relay is in a different spot than every other E class. All the other E class fuel pump relays are in the drivers side with the SAM. E55 and E63 are in the passenger side. Again, not sure about the wagon.
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2005 e55 AMG
Just to make sure you remember and Im sure you do but.....There will only be voltage when cycling the key for just a second and then shuts off so if key is on and you walk around the car to test it,no voltage.
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From: America
1999 C43 AMG, 2005 E55 Wagon
I actually didn't know this. So it might be bad fuel pumps after all. Best test is to put 12v directly at the hot lug for the pump? Sounds dangerous with it being inside the fuel tank. Could it arc?
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From: Republic of Texas
'99 and '05 E55 AMG
I've made multiple posts on this. " Verify parts!" Is one of them. Search on my user name for anything pertaining to E55 fuel pumps and relays.
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1999 C43 AMG, 2005 E55 Wagon
I've seen all your posts but it's hard to know the difference between sedan and wagon. I've replaced the 3 relays in the rear (where the dealer said it was) and nothing changed. Is the pump relay somewhere else and the dealer is wrong?
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'99 and '05 E55 AMG
Multiple edits. Sigh...
You might have a "unicorn"; check your build date.
Four harnesses; start of production through 20 March 2003, 21 March 2003 through 31 August 2003, 01 September 2003 through 31 May 2005, 01 June 2005 through 31 May 2006. All for the E55.
If you have an '05, there should be only two relays in the passenger side rear. 01 June 2006 production run removed the relays and inserted two each PWM modules for the E63 fuel pumps.
Pull the relays in the rear and jumper the relay connections that feed power to the pumps. You'll recognize the SAI pump because it sounds like a turbine under the driver side front bumper. You can find the fuel pump relay because you will have 12 volts on either pins 1 and 3 (gen 1 pumps) or pins 2 and 3 (gen 2 pumps with adapter cable) at the fuel pumps hat. With power off, check for continuity between relay power out connection and the fuel pump top hat connector. Pins 1 & 3 if no adapter cable, pins 2 & 3 with adapter cable. Check for short to chassis but I doubt that as it would blow the 30-amp fuse.
Hang in there. Take notes and attack the problem logically. You'll figure it out and you'll slap your forehead when you do.
You might have a "unicorn"; check your build date.
Four harnesses; start of production through 20 March 2003, 21 March 2003 through 31 August 2003, 01 September 2003 through 31 May 2005, 01 June 2005 through 31 May 2006. All for the E55.
If you have an '05, there should be only two relays in the passenger side rear. 01 June 2006 production run removed the relays and inserted two each PWM modules for the E63 fuel pumps.
Pull the relays in the rear and jumper the relay connections that feed power to the pumps. You'll recognize the SAI pump because it sounds like a turbine under the driver side front bumper. You can find the fuel pump relay because you will have 12 volts on either pins 1 and 3 (gen 1 pumps) or pins 2 and 3 (gen 2 pumps with adapter cable) at the fuel pumps hat. With power off, check for continuity between relay power out connection and the fuel pump top hat connector. Pins 1 & 3 if no adapter cable, pins 2 & 3 with adapter cable. Check for short to chassis but I doubt that as it would blow the 30-amp fuse.
Hang in there. Take notes and attack the problem logically. You'll figure it out and you'll slap your forehead when you do.
Last edited by bbirdwell; Jun 26, 2023 at 08:58 AM.
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1999 C43 AMG, 2005 E55 Wagon
provided picture of situation in the rear.
On a hunch, since the dealer was oddly not hempful on the relay location, i considered they might have ene given me the wrong relay. Your pics, bbirdwell, indicate its the smaller black one at very bottom. But they sold me one of the larger black ones. I used the new one to try and start the car by swapping it in place of all the areas where a similar black one us used back here. No luck. But again, your picture indicates bottom smaller one is for both fuel pump and intercooler pump.
I go back with the smaller one and just asked for a new one. Got one.
Install it into car, and for the first time in 4 days it finally tried to start. But only 1 or 2 cylinders fired before it dies again and the situation remains the same. No start, no fuel pressure at rail.
I pull the relay and jumper between lugs 3 and 5 as the diagram indicates thats what closes the circuit. No change.
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1999 C43 AMG, 2005 E55 Wagon
Ignore all of this, I'm an absolute moron. It is the same as the sedan, just hidden behind subwoofer behind other panel. Thank you for trying to guide me through my own stupidity bbirdwell and sicamg
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'99 and '05 E55 AMG
?
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2005 e55 AMG
Oh please....you know how many times I chased issues that were right there in front of my face and didn't even see it ? No worrys !!!
Also now that you know, carry a spare relay like I do....along with a crank sensor. You never know and they are really small so they don't take up any room to bother you in the glove box so at least if needed they are right there. You will be like a rolling NAPA store with parts in stock LOL.
Glad you got it solved plus if bbirdwell couldn't figure it out then you'd be really screwed LOL !!
Also now that you know, carry a spare relay like I do....along with a crank sensor. You never know and they are really small so they don't take up any room to bother you in the glove box so at least if needed they are right there. You will be like a rolling NAPA store with parts in stock LOL.
Glad you got it solved plus if bbirdwell couldn't figure it out then you'd be really screwed LOL !!
Last edited by SICAMG; Jun 25, 2023 at 11:18 AM.
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2002 S430 and 2005 E55 AMG
Member
Joined: Apr 2020
Posts: 75
Likes: 22
2002 S430 and 2005 E55 AMG
Thread Starter
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From: America
1999 C43 AMG, 2005 E55 Wagon
Yes it's on passenger side behind subwoofer. I asked the dealer for a diagram to be sure which relay I'm replacing and they printed out the diagram for driver side SAM!
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1999 C43 AMG, 2005 E55 Wagon
Having been confined to my wife's G500 for the last 5 days (slow), I was so excited to get the E55 back out on the roads today. Got to race a new M3 (and lost, of course) but it was still fun.
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From: America
1999 C43 AMG, 2005 E55 Wagon
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2002 S430 and 2005 E55 AMG
in 2007 they went to a dual relay setup on the E63 because they were having trouble with the pigtails melting. I changed my 05 over to dial relays after having that problem and I haven’t had that issue since.
