E55 Fuel Pump Relays through the years
04-25-2017, 10:45 AM
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'99 and '05 E55 AMG
E55 Fuel Pump Relays through the years
I now have better information about the fuel pump relays on the E55s through the years.
2003 and early 2004 - Air pump relay over auxiliary battery, single fuel pump relay on passenger side of trunk next to air reservoir.
There was a harness change on 1 September 2003 so not sure if some later-build 2004s have the following configuration.
2005 - Air pump relay and single fuel pump relay on passenger side of trunk next to air reservoir. This setup has the ECU controlling the relay via a single line. Relay is rated for 40 amps and it carries 26 amps with new pumps and filters.
2006 (any E55 manufactured on or after 1 June 2005) - Air pump relay and dual fuel pump relays on passenger side of trunk next to air reservoir. This setup has the ECU controlling each relay via a single line (different pinout on the ECU compared to previous year). Relays are rated for 40 amps and each relay carries 13 amps with new pumps and filters.
Many thanks to Austin for taking the time to pull the panel on his new to him E55 and confirm the relays.
Important trivia for you: if you measure 12-13 amps on one pump but only 3 amps on the other pump, the low-amperage pump is wired backwards. Usually means you do not have the adapter harness installed to account for the harness change to the fuel pumps in later versions of the pumps.
2003 and early 2004 - Air pump relay over auxiliary battery, single fuel pump relay on passenger side of trunk next to air reservoir.
There was a harness change on 1 September 2003 so not sure if some later-build 2004s have the following configuration.
2005 - Air pump relay and single fuel pump relay on passenger side of trunk next to air reservoir. This setup has the ECU controlling the relay via a single line. Relay is rated for 40 amps and it carries 26 amps with new pumps and filters.
2006 (any E55 manufactured on or after 1 June 2005) - Air pump relay and dual fuel pump relays on passenger side of trunk next to air reservoir. This setup has the ECU controlling each relay via a single line (different pinout on the ECU compared to previous year). Relays are rated for 40 amps and each relay carries 13 amps with new pumps and filters.
Many thanks to Austin for taking the time to pull the panel on his new to him E55 and confirm the relays.
Important trivia for you: if you measure 12-13 amps on one pump but only 3 amps on the other pump, the low-amperage pump is wired backwards. Usually means you do not have the adapter harness installed to account for the harness change to the fuel pumps in later versions of the pumps.
Last edited by bbirdwell; 04-25-2017 at 10:49 AM.
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MACEDON (04-25-2017)
04-25-2017, 03:22 PM
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'99 and '05 E55 AMG
I don't believe that for a moment, Ghost Rider! In all seriousness, the E55's single fuel pump relay is a weak point; multiple folks on this forum (to include me) had the relay melt and put the fuel system out of commission. Quite the pucker factor in rush-hour traffic on an elevated expressway.
(Fun trivia: the melted plastic housing means the temperature of the relay was over 300 degrees F when it failed.)
In several cases, the cars would run fine and then just quit every few minutes. Throws no codes so you have to literally eyeball the relay. And many new E55 owners are using the fuse/relay diagram for the non-AMG W211's; they are *not* the same. E55 uses a modified wiring harness.
The 06 dual relay should greatly reduce the risk of a melted relay putting the car on the side of the road. I'm trying to figure out how to do this in my car but do not believe my single-line ECU can drive two relays; I'll have to have the ECU line drive a single relay which in turn drives two relays for the fuel pumps.
If this is your first E55, PM me your email address.
(Fun trivia: the melted plastic housing means the temperature of the relay was over 300 degrees F when it failed.)
In several cases, the cars would run fine and then just quit every few minutes. Throws no codes so you have to literally eyeball the relay. And many new E55 owners are using the fuse/relay diagram for the non-AMG W211's; they are *not* the same. E55 uses a modified wiring harness.
The 06 dual relay should greatly reduce the risk of a melted relay putting the car on the side of the road. I'm trying to figure out how to do this in my car but do not believe my single-line ECU can drive two relays; I'll have to have the ECU line drive a single relay which in turn drives two relays for the fuel pumps.
If this is your first E55, PM me your email address.
04-04-2020, 10:13 AM
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This place is a joke.
At this point in the E55 life cycle anyone who cannot work on their own cars should not be buying one, unless you have disposable income to pay someone else to do it, and knowing at some point the repairs will exceed the value of the car.
It sounds like you don't meet the above criteria.
It sounds like you don't meet the above criteria.
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MJBelcher500 (11-19-2022)
04-04-2020, 10:42 AM
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'99 and '05 E55 AMG
At this point in the E55 life cycle anyone who cannot work on their own cars should not be buying one, unless you have disposable income to pay someone else to do it, and knowing at some point the repairs will exceed the value of the car.
It sounds like you don't meet the above criteria.
It sounds like you don't meet the above criteria.
11-18-2022, 09:57 PM
#7
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I don't believe that for a moment, Ghost Rider! In all seriousness, the E55's single fuel pump relay is a weak point; multiple folks on this forum (to include me) had the relay melt and put the fuel system out of commission. Quite the pucker factor in rush-hour traffic on an elevated expressway.
(Fun trivia: the melted plastic housing means the temperature of the relay was over 300 degrees F when it failed.)
In several cases, the cars would run fine and then just quit every few minutes. Throws no codes so you have to literally eyeball the relay. And many new E55 owners are using the fuse/relay diagram for the non-AMG W211's; they are *not* the same. E55 uses a modified wiring harness.
The 06 dual relay should greatly reduce the risk of a melted relay putting the car on the side of the road. I'm trying to figure out how to do this in my car but do not believe my single-line ECU can drive two relays; I'll have to have the ECU line drive a single relay which in turn drives two relays for the fuel pumps.
If this is your first E55, PM me your email address.
(Fun trivia: the melted plastic housing means the temperature of the relay was over 300 degrees F when it failed.)
In several cases, the cars would run fine and then just quit every few minutes. Throws no codes so you have to literally eyeball the relay. And many new E55 owners are using the fuse/relay diagram for the non-AMG W211's; they are *not* the same. E55 uses a modified wiring harness.
The 06 dual relay should greatly reduce the risk of a melted relay putting the car on the side of the road. I'm trying to figure out how to do this in my car but do not believe my single-line ECU can drive two relays; I'll have to have the ECU line drive a single relay which in turn drives two relays for the fuel pumps.
If this is your first E55, PM me your email address.
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11-18-2022, 11:18 PM
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'99 and '05 E55 AMG
You want something like this. You will only use four of the wires. Just repair each connector one at a time so you do not miswire the relay. I have posted the relay schematics in several threads in the subforum and you will find them with a search.
Last edited by bbirdwell; 11-18-2022 at 11:23 PM.
11-18-2022, 11:55 PM
#9
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https://www.amazon.com/dp/B01KFKEFZA...1babee253ba10e
You want something like this. You will only use four of the wires. Just repair each connector one at a time so you do not miswire the relay. I have posted the relay schematics in several threads in the subforum and you will find them with a search.
You want something like this. You will only use four of the wires. Just repair each connector one at a time so you do not miswire the relay. I have posted the relay schematics in several threads in the subforum and you will find them with a search.
