P2540 pops-up when I connect a scan tool
Thread Starter
Junior Member
Joined: Jun 2017
Posts: 15
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From: Dallas TX area
2009 E63 AMG
P2540 pops-up when I connect a scan tool
I purchased a 2009 E63 on Sunday.
The car had 955xx miles on it, and was in top-notch condition.
On Monday morning, I took the car to a state inspection station.
They failed me because their equipment couldn't connect to the computer.
I took it home and I was able to connect to the computer only with the key in the "ON" position... engine not running.
I also noticed that when my scan tool connected to the computer, the "check engine" light illuminated. I found a P2540. I cleared it, and it didn't come back.
I took the car to the inspection station this morning, and told themto try connecting with the key on, engine off. That worked, but therewere not enough "ready" codes set to pass inspection... bummer.
I took my second "fail" papers and left. When I got back in the car, the "check engine" was illuminated again. I cleared the code with my scan tool.
I searched this forum and part of the internet, and I was unable to findany other folks that mentioned a code popping-up when they connected a scan tool.
I am a "frugal" guy, and I don't want to simply take it to the dealer.
I need suggestions on how to get this car to pass inspection.
Thanks,
The car had 955xx miles on it, and was in top-notch condition.
On Monday morning, I took the car to a state inspection station.
They failed me because their equipment couldn't connect to the computer.
I took it home and I was able to connect to the computer only with the key in the "ON" position... engine not running.
I also noticed that when my scan tool connected to the computer, the "check engine" light illuminated. I found a P2540. I cleared it, and it didn't come back.
I took the car to the inspection station this morning, and told themto try connecting with the key on, engine off. That worked, but therewere not enough "ready" codes set to pass inspection... bummer.
I took my second "fail" papers and left. When I got back in the car, the "check engine" was illuminated again. I cleared the code with my scan tool.
I searched this forum and part of the internet, and I was unable to findany other folks that mentioned a code popping-up when they connected a scan tool.
I am a "frugal" guy, and I don't want to simply take it to the dealer.
I need suggestions on how to get this car to pass inspection.
Thanks,
Last edited by e63_in_dfw; Jun 7, 2017 at 04:07 PM. Reason: clean-up
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From: Republic of Texas
'99 and '05 E55 AMG
https://mbworld.org/forums/e-class-w...ml#post7144496
That's the drive cycle to get the ready codes set.
Your fault code is: P2540 - Low Pressure Fuel System Sensor Circuit Range/Performance.
Hopefully it is just a sensor issue. If not, figure it out quickly because you can destroy your engine if fuel pressure is insufficient to maintain proper air/fuel ratios. May be as simple as a clogged fuel filter. May be the pumps are going bad.
That's the drive cycle to get the ready codes set.
Your fault code is: P2540 - Low Pressure Fuel System Sensor Circuit Range/Performance.
Hopefully it is just a sensor issue. If not, figure it out quickly because you can destroy your engine if fuel pressure is insufficient to maintain proper air/fuel ratios. May be as simple as a clogged fuel filter. May be the pumps are going bad.
Last edited by bbirdwell; Jun 6, 2017 at 10:59 AM.
Super Member
Joined: Jan 2016
Posts: 599
Likes: 120
2004 E55
I purchased a 2009 E63 on Sunday.
The car had 955xx miles on it, and was
in top-notch condition.
On Monday morning, I took the car to a state inspection station.
They failed me because their equipment couldn't connect to the computer.
I took it home and I was able to connect to the computer only with
the key in the "ON" position... engine not running.
I also noticed that when my scan tool connected to the computer, the
"check engine" light illuminated. I found a P2540. I cleared it, and it didn't come back.
I took the car to the inspection station this morning, and told them
to try connecting with the key on, engine off. That worked, but there
were not enough "ready" codes set to pass inspection... bummer.
I took my second "fail" papers and left. When I got back in the car,
the "check engine" was illuminated again. I cleared the code with my
scan tool.
I searched this forum and part of the internet, and I was unable to find
any other folks that mentioned a code popping-up when they connected
a scan tool.
I am a "frugal" guy, and I don't want to simply take it to the dealer.
I need suggestions on how to get this car to pass inspection.
Thanks,
The car had 955xx miles on it, and was
in top-notch condition.
On Monday morning, I took the car to a state inspection station.
They failed me because their equipment couldn't connect to the computer.
I took it home and I was able to connect to the computer only with
the key in the "ON" position... engine not running.
I also noticed that when my scan tool connected to the computer, the
"check engine" light illuminated. I found a P2540. I cleared it, and it didn't come back.
I took the car to the inspection station this morning, and told them
to try connecting with the key on, engine off. That worked, but there
were not enough "ready" codes set to pass inspection... bummer.
I took my second "fail" papers and left. When I got back in the car,
the "check engine" was illuminated again. I cleared the code with my
scan tool.
I searched this forum and part of the internet, and I was unable to find
any other folks that mentioned a code popping-up when they connected
a scan tool.
I am a "frugal" guy, and I don't want to simply take it to the dealer.
I need suggestions on how to get this car to pass inspection.
Thanks,
If it is coming back on after being cleared there is a hard fault that needs to be resolved.
In this case it looks like the fuel pumps have a fault the needs to be resolved (replacing fuel pumps).
https://mbworld.org/forums/c63-amg-w...uel-sytem.html
^+1 on what Barry linked up, you maybe able to clear it then meet the drive cycle requirements to pass without replacing the pumps but I guess I am still stuck with a gut feeling that the car is reporting the CEL as the pending fault that had its final fault criteria met and triggered the CEL lamp to activate.
Regardless of your pass fail it probably would be a good idea to see if you could get a SDS scan tool hooked up to see what is going on
Last edited by BoostedAero; Jun 6, 2017 at 11:10 AM.
Thread Starter
Junior Member
Joined: Jun 2017
Posts: 15
Likes: 0
From: Dallas TX area
2009 E63 AMG
But...
If it were a real fault, wouldn't it illuminate the "check engine" more often instead of only when a scan tool is connected?
I have driven the car well over 100 miles since I bought it. It only triggered the code when I connected a scan tool.
After I cleared the code, I drove it for nearly an hour before I got to the inspection station. As soon as they connected their scan tool, it triggered the code.
Both codes were triggered with the key on and engine off. Could that be the only time the computer checks the fuel pressure?
I have KEYLESS GO, so I usually sit down, step on brake, and push the button. The car is usually in "key on, engine off" for only a moment... hmmm.
Maybe I'll start the car with a key for a couple days and see if I can get the P2540 to come back without a scan tool.
Are there codes that are only triggered when a scan tool is connected?
Thanks for all the help,
Last edited by e63_in_dfw; Jun 7, 2017 at 04:08 PM. Reason: clean-up
Thread Starter
Junior Member
Joined: Jun 2017
Posts: 15
Likes: 0
From: Dallas TX area
2009 E63 AMG
update...
After work, I started the car with the key... flipping the key to '2' and letting it sit there for a few seconds before starting. I saw no 'check engine' light.
I followed the OBD II drive cycle as best I could on the way home... idle for a few minutes ,then drive certain way for a while. I saw no 'check engine' light on my 28-mile trip home.
This morning, I started the car with the key... flipping the key to '2' and letting it sit there for a few seconds before starting. I got my 'check engine' light right away! ... without connecting a scan tool.
So... I'm concluding that the scan tool was not the reason for my code; it must have been the sorry, low-down, good-for-nothing seller resetting the code and hoping the test drive didn't trigger the code before he sold it
What should my next diagnostic steps be?
I need to get plates on this thing, but I can't do that without passing the inspection
After work, I started the car with the key... flipping the key to '2' and letting it sit there for a few seconds before starting. I saw no 'check engine' light.
I followed the OBD II drive cycle as best I could on the way home... idle for a few minutes ,then drive certain way for a while. I saw no 'check engine' light on my 28-mile trip home.
This morning, I started the car with the key... flipping the key to '2' and letting it sit there for a few seconds before starting. I got my 'check engine' light right away! ... without connecting a scan tool.
So... I'm concluding that the scan tool was not the reason for my code; it must have been the sorry, low-down, good-for-nothing seller resetting the code and hoping the test drive didn't trigger the code before he sold it
What should my next diagnostic steps be?
I need to get plates on this thing, but I can't do that without passing the inspection
Last edited by e63_in_dfw; Jun 7, 2017 at 04:05 PM. Reason: typo
Super Member
Joined: Dec 2015
Posts: 638
Likes: 83
From: Dublin,OH. Ft Myers, FLA
E63 AMG 2007
You need to get it on a scan tool like Boosted said. These cars are very complicated and guessing and replacing parts is not a good plan. Establish a relationship with a dealer or good independent shop and have it properly diagnosed. When you know what it is, the site can help you with how to go about making it right. Most everyone on this site has put significant investment into their "new" "top notch condition" AMG. It's part of the experience. 
Thread Starter
Junior Member
Joined: Jun 2017
Posts: 15
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From: Dallas TX area
2009 E63 AMG
MB II scan tool is on the way.
Meanwhile, I was able to use Torque android app on the way home. I saw fuel pressure values between 50 and 60 all the way home. What is the fuel pressure supposed to be?
Meanwhile, I was able to use Torque android app on the way home. I saw fuel pressure values between 50 and 60 all the way home. What is the fuel pressure supposed to be?
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MBWorld Fanatic!
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From: Republic of Texas
'99 and '05 E55 AMG
For an M156 engine, 4.6 Bar or 66 psi measured at idle.
If you put it on a diagnostic system, go to Control Units/Drive/Fuel Pump and you can read out the measured values to include pressure and amperage draw by the fuel pumps.
Your car is telling you the fuel pressure is low. Pumps, filter, or sensor. One or all of them are bad. If it is only one pump, the low pressure would only show up at full throttle and higher rpms.
Trivia for the day. If one replaces a fuel pump controller, it must be activated using Star or malfunctions can occur.
If you put it on a diagnostic system, go to Control Units/Drive/Fuel Pump and you can read out the measured values to include pressure and amperage draw by the fuel pumps.
Your car is telling you the fuel pressure is low. Pumps, filter, or sensor. One or all of them are bad. If it is only one pump, the low pressure would only show up at full throttle and higher rpms.
Trivia for the day. If one replaces a fuel pump controller, it must be activated using Star or malfunctions can occur.
Last edited by bbirdwell; Jun 8, 2017 at 12:31 PM.
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2004 E55
If you put it on a diagnostic system, go to Control Units/Drive/Fuel Pump and you can read out the measured values to include pressure and amperage draw by the fuel pumps.
Trivia for the day. If one replaces a fuel pump controller, it must be activated using Star or malfunctions can occur.
Trivia for the day. If one replaces a fuel pump controller, it must be activated using Star or malfunctions can occur.
I bet, fuel pumps/sending unit + SDS would be cheaper than having just the pumps done by a dealer
Thread Starter
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Joined: Jun 2017
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From: Dallas TX area
2009 E63 AMG
Has anyone tried stuffing an aftermarket pump into the OE bucket?
Is the OE system a return-style [pump, regulator, return line] or is it a returnless [pump, pressure sensor, computer-controlled voltage] system?
Is the OE system a return-style [pump, regulator, return line] or is it a returnless [pump, pressure sensor, computer-controlled voltage] system?
Last edited by e63_in_dfw; Jun 8, 2017 at 06:04 PM. Reason: typo
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From: Republic of Texas
'99 and '05 E55 AMG
Returnless. Just like the E55. Do a search on "E63 fuel system" or "E55 fuel system" and you'll find an image. Or better yet, sign up with the Electronic Parts Catalog and you can look up the latest parts yourself.
Research, research, research. The truth is out there.
Thread Starter
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Joined: Jun 2017
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From: Dallas TX area
2009 E63 AMG
I removed the pumps Saturday to look them over... Could they have made this setup any more complicated? 
The OE pumps are significantly different compared to the Walbro in-tank pumps I'm familiar with, so I won't be installing aftermarket pumps.
Plus, I have no idea if the current-draw and flow characteristics of the OE pumps are even close to those of the Walbro pumps - I'd hate to BBQ the FP controller.
I ordered the fuel pump assembly [211-470-36-94] and the sender assembly [new part number 211-470-63-94] from my local dealer. They matched the pricing I saw online! Plus I won't have to pay for shipping!. Parts should be here tomorrow morning.
I'm on a deadline... once you fail a TX state inspection, you have 15 days to correct the problem, or you have to pay the inspection fee, again. Today is day #7.
If anyone needs photos of E63 fuel system parts, speak-up, and I'll see if I can get them for you.
On a side note...
I was surprised to find VW / Audi logos on a couple of the connectors I encountered. Isn't that like finding Ford parts on a Chevy?
The OE pumps are significantly different compared to the Walbro in-tank pumps I'm familiar with, so I won't be installing aftermarket pumps.
Plus, I have no idea if the current-draw and flow characteristics of the OE pumps are even close to those of the Walbro pumps - I'd hate to BBQ the FP controller.
I ordered the fuel pump assembly [211-470-36-94] and the sender assembly [new part number 211-470-63-94] from my local dealer. They matched the pricing I saw online! Plus I won't have to pay for shipping!
. Parts should be here tomorrow morning.I'm on a deadline... once you fail a TX state inspection, you have 15 days to correct the problem, or you have to pay the inspection fee, again. Today is day #7.
If anyone needs photos of E63 fuel system parts, speak-up, and I'll see if I can get them for you.
On a side note...
I was surprised to find VW / Audi logos on a couple of the connectors I encountered. Isn't that like finding Ford parts on a Chevy?
Thread Starter
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Joined: Jun 2017
Posts: 15
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From: Dallas TX area
2009 E63 AMG
I know it's been over a month since I posted this, but I thought I'd update my status.
I put the pumps and filter in on a Friday evening. I got around to plugging-in everything and discovered that the updated filter assembly has a different wiring connector on the top of the module
I tracked-down the 211-440-05-07 that I needed at the dealer in Plano. Early Saturday morning, I picked it up and everything went back together with no issues. The car started and ran just fine.
I followed the OBD-II drive cycle recipe on my trip to the inspection station [27-28 miles away]. I pulled-over to check for codes and ready flags just before I got there. Enough flags were 'ready' and I had no codes!
I passed inspection with ease... I had one entire day to spare of my 15-day window.
I've been driving it since then with no issues... other than only getting about 18 mpg when I was used to getting 48.
This car doesn't have the low-end grunt like the E55s I drove, but the interior is so nice and I couldn't pass on the price
I put the pumps and filter in on a Friday evening. I got around to plugging-in everything and discovered that the updated filter assembly has a different wiring connector on the top of the module
I tracked-down the 211-440-05-07 that I needed at the dealer in Plano. Early Saturday morning, I picked it up and everything went back together with no issues. The car started and ran just fine.
I followed the OBD-II drive cycle recipe on my trip to the inspection station [27-28 miles away]. I pulled-over to check for codes and ready flags just before I got there. Enough flags were 'ready' and I had no codes!
I passed inspection with ease... I had one entire day to spare of my 15-day window.
I've been driving it since then with no issues... other than only getting about 18 mpg when I was used to getting 48.
This car doesn't have the low-end grunt like the E55s I drove, but the interior is so nice and I couldn't pass on the price
