My first time posting on the forum, so thanks in advance for the help.

I have a 2003 e320 with 150K miles on it. A week ago it died and after some troubleshooting it was determined that the fuel pump had gone out ( it was still the original pump and sending unit).

I purchased a new pump and sending unit, but now after installing them, the car still will not start and I am not getting any gas pressure to the fuel line or to the rail. The pump does not come on at all.

The car cranks and turns over, but no fuel and obviously will not start.

I have checked the relay and fuse, both are fine. I can hook the sending unit and pump directly to a battery and they run fine.

However, when plugged into the wiring harness, I am getting no power and no fuel pressure.

I have checked both batteries and they are strong 11.9V on the main. The aux is also good.

I hooked up my Icarsoft 980 and I am getting the following errors on the ME – 9086 “The measured value of the component B4/1 (fuel gauge sensor, left half of tank) is outside the tolerance range. I get the same message 9085 …B4/2.(fuel gauge sensor, right half of tank)….

I am wondering if this is causing the ECU to not power up the pump? I have searched and cannot find out what this error code means.

Is this perhaps the float sensors on the pump and sending unit? Or are there some other sensors on each side of the fuel tank that I am not aware of?

Any assistance or recommendations would be greatly appreciated.

 

Hi!

Welcome to MBworld!

Your best bet for help is from fellow owners, moving your post to the E-Class(W211). Good luck trouble shooting!

Bob

 

Thanks, my bad. I thought I was no this forum when I poste. Thanks for moving it over

 

Three articles in the "Fuel Injection" section.
https://www.pelicanparts.com/techart...Index-W211.htm

The article on fuel pump testing will walk you through the steps for electrical testing. Follow those and then get back to us. The other articles' comments section explain the error code which is caused by an open circuit, a short circuit, or jammed/blocked floats.

 

Thanks, I will check again and report back.

 

Ok, after going through the electrical testing, I am getting 11.2 V on the pump wiring harness when I turn the key to the on position for about 3 seconds then it drops off (I know this is to create the pressure and is what is expected). When I turn the key to start the car, I am only getting about 9.3 V during the cranking of the car.

 

I would replace the main battery. If in doubt, connect a battery charger to the main battery (with the key fob out of the ignition!) and then attempt to start the car. Positive lead to the battery positive post, negative lead to the BCM (Battery Control Module) ground lug or any good chassis ground).

Whenever the battery voltage drops below 10 volts, expect multiple modules on the distributed digital control bus to fail. Whenever my main bus battery voltage displayed 12.1 volts or less as indicated in the Instrument Cluster my car would fail to start or run. Search and you will find how to display "USB voltage" on the W211 instrument cluster.

FWIW, I use a Solar BA-50 Battery Tester. New, the 900-rated CCA main battery will test over 1050 CCA. Whenever the battery tests at 650 CCA or below, my car will not start or run. Blows my mind that 650 CCA will not ensure my car will start. Heck, I still take my worn out batteries out of my Miata (only 320 CCA new!), put them in my garden tractor, and those batteries will crank and start my garden tractor for an additional two years! Yes, an NA Miata battery is a direct replacement for a garden tractor battery...

You have >30 digital modules in a W211 and low voltage at any time (especially cranking the engine) plays havoc with the electronics.

 

Thanks, very much. I will replace the battery today and report back.

 

I don't think replacing the battery will fix your fuel pump problem.

 

I have hooked up my battery charger to test the voltage when cranking. However, I have my suspicions as well. Any suggestions?

I

 

sorry for the delay. I have been out to town so had to put this on hold for a few days.

I had both batteries tested and wound up replacing the Aux battery. I was marginal. The main battery was tested and in good shape.

So now I have gone through all DTC's with my iCarsoft scanner and I am getting the following errors on ME and Rear Sam.

The ME I am getting three errors: P203A-008: See tank level sensor (P1999) DTC Status: Stored
P201C-001 (Fuel tank pressure sensor) : Short Circuit to positive (P0453) DTC Status: Fault indicator lamp on
P201C-016 The fault code is not found in the database
On the rear SAM I am getting two errors: 9086 The measured value of component B4/1 (fuel gauge sensor, left half of tank) is outside the tolerance range, DTC status: stored
9085 The measure value of component B4/2 (Fuel gauge sensor, right half of tank) is outside the tolerance range, DTC status: stored

This seems like some kind of electrical issue.

Is it possible that the sending unit is somehow malfunctioning? I did replace it, but it was with a generic one I bought on Amazon.

Any suggestions would be appreciated.

Thanks

 

Also, just for clarification. I replaced both the fuel pump and the sending unit. I can bypass the wiring harness and hook up the sending unit directly to the battery and the fuel pump runs. I am just not getting any power to the unit when plugged into the wiring harness and turning on the car.

 

Help, I still have not been able to get this fixed. I have replaced the Sending Unit with and OEM VDO unit cthat I bought from Pelican Parts. I an still bypass the wiring harness and get it the fuel pump to run.

I was orginally hopeful that this was going to solve the issue as the previous DTC error codes disappeared. However, after trying to start the car a number of times, the same codes have poped back up.

On the ME I am getting three errors: P203A-008: See tank level sensor (P1999) DTC Status: Stored
P201C-001 (Fuel tank pressure sensor) : Short Circuit to positive (P0453) DTC Status: Fault indicator lamp on
P201C-016 The fault code is not found in the database
On the rear SAM I am getting two errors: 9086 The measured value of component B4/1 (fuel gauge sensor, left half of tank) is outside the tolerance range, DTC status: stored
9085 The measure value of component B4/2 (Fuel gauge sensor, right half of tank) is outside the tolerance range, DTC status: stored

Is there some sensor that I am not aware of? Is this some kind of potential wiring issue?

Please, please let me know if you can point me in a direction? My car hasnt run for a month and I am afraid my next step is going to be having it towed to a mechanic.

Thanks for any suggestions.

 

Still have the old pump? Curious if that one runs if you power it directly. Got spark? Did the car die while driving, or just not start one day? I'm assuming the car needs to see a rpm/engine speed signal to power the pump past it's initial prime (crank position sensor)

 

Thanks so much for responding.

Yes, I kept the old pump and it was definitely dead . It does not do anything when you connect it directly to a battery.

The car died while driving it home within a block of my house.

I also connected the new VDO sending unit to the fuel pump before installing it. I hooked it up to the battery and it ran fine.


When I check the Voltage on the main and ground on the wiring harness, I get 11.6 V for the initial 2-3 seconds, but the pump itself does not crank up so I get no fuel pressure and nothing on the fuel rail at all.

I definitely feel like something is not sending a signal to tell the fuel pump to run.

Any ideas?

 

Hoping that someone might have some ideas on this? Thanks

 

Ok, still at this... One thing I noticed is that my fuel gauge shows that the tank is half full (which is what it should be - so it seems the float sensors on the sending unit and pump are working), but the low fuel light is on.

I am obviously grasping at straws here, could this be what is causing the no power to the fuel pump issue?

 

What part number fuel pump and sender did you install? The senders and pumps we're redesigned post 04 or 05 and the gauges use different ranges than your 03. There is some SDS coding involved.

 

Ok, very interesting . I will check and post back this afternoon.

 

These are the parts I ordered and installed.

Fuel Pump: Herko Automotive: Manufacturer Part Number: 263GE (OE replacement for - E8530M 2114701494 67972 A2114702994 P3227) - bought on Amazon

Sending Unit: Mercedes-Benz Fuel Pump Assembly with Fuel Level Sending Unit - (Transfer Pump) - Continental VDO 228-242-010-006Z - purchased from Pelican Parts

 

In the post above by Tjts1. Are you saying that I need to get someone with the Star Diagnostics Software to do some kind of programing to get the new fuel pump to work?

 

No programming required. Plug and play.

-Do the pumps energize for one second when the key is turned on?
-If not, will the pumps energize when you jumper the relay positions? (Search for the two proper connections so you don't eff it up and burn the harness or burn out the motor electronics. Pelican Parts article above explained it.)
-If pumps energize when key turns on, then de-energize as programmed, do they re-energize when the key is turned to the start position and the crankshaft begins rotating?
--If yes, they re-energize, verify fuel pressure on rail. If good, it's not the fuel pressure; look for an electrical problem to the injectors or the coils.
--If no, pumps do not re-energize, this indicates the ME (motor electronics) is not receiving a signal from the crank position sensor. Proper sequence: key on, fuel pumps on for one second, then fuel pumps off until motor electronics receive a signal from the crankshaft position sensor indicating the crankshaft is rotating. Safety feature so as to turn off fuel pumps in event of an accident and the engine quits. Stop pumping fuel to reduce risk of fire and death.

So:
-do the pumps energize when you turn the key on?
-do the pumps energize when the crankshaft is rotating?
-if yes to the above, look electrical and not fuel.
-if no to either of the above, follow the fault tree to determine where the electrical circuit has failed the fuel pump.

 

bbirdwell, thanks so much for responding. Ok the answer to your questions is

No, when I have the wiring harness plugged into the sending unit and turn the key on, nothing. No 2-3 second spin up of the pump - nothing. Same when I crank it. Nothing.

So, I tried bypassing the wiring harness and I alligator clipped the power and the ground (from the harness) into the the two pins on the sending unit. The pump runs and the car starts and I ran it for 5 min with no issues.

So then I checked my iCarsoft980 for DTC's I am still getting the following

ME2; P203A-008 (1/3) Fuel Tank level: See tank sensor (P1999) DTC status: stored
P201C-001(2/3) (fuel pressure sensor): Short circuit to positive (p0453) DTC status: fault indicator light is on
P201C-016 (3/3) This fault code is not found in database

Rear SAM:
9086 (1/2) The measured value of the component B4/1 (fuel gauge sensor, left half of tank) is outside the tolerance range. DTC Status: Stored
9085 (2/2) The measured value of the component B4/2 (fuel gauge sensor, right half of tank) is outside the tolerance range. DTC Status: Stored

I also noticed that my fuel level is showing half full (which is correct), but the low fuel light is on.

So I am guessing it comes down the something in the wiring or the ME is causing the pumps to not come on.

There are 5 wires in the wiring harness. Obviously the power and the ground are working as I am able to get the pumps to work with the key on and wired directly to the power and ground pins on the pump.

I am guessing the blue wire is the tank level as that seems to be the wire hooked up internally to the level sensors.

So what do the other wires do? I suspect that one of the these is the culprit. So it is either one of the wires is grounded and not allowing the pumps to start? Or is this computer related because of the sensor which It assume is built into the sending unit/pump?

I think we are making progress here in narrowing down what is causing the issue.

What would you suggest as next steps?

Thanks

 

Codes are stored, not current; that means bad in the past but not bad now. The fuel level floats are on a completely different circuit than the fuel pump power. Fuel pressure sensor we can figure out in the future once we get your car running.

Go here and look at the schematic; but first, pull and replace your fuel pump relay. It's only a few bucks and an easy check to perform. Then go to the following:
https://mbworld.org/forums/w211-amg/...3.html#post812 0332
Note the above is for an E55 and not your car! You only want to look at the relay connections! Pins 86, 87, 85, and 30.

-Remove relay. With key on, do you have 12 volts on pin 30. If yes, fuse is good and wire connection is good. If no voltage, check fuse and search for shorts or broken conductors back to the pre-fuse box. (Remember, the above is for an E55 and not your car.)
-Jumper with spade connectors (or even a paper clip; warning, it will get hot!) pins 30 and 87. Turn key to position 2 (Run). If the pump energizes, the power circuit to the pump is good. Short term only as the fuel pump pulls a lot of current and will melt the paper clip. Also, the paper clip can/will damage the sockets; thus why I recommend you use spade connectors. A few more minutes now but saves time in the future.
-Remove jumper above. Install an LED tester between pins 86 and 85. Key on to position 2 (run) the LED should light for ~1 second then turn off. Turn key to "start" position and the LED should light up continuously.
----If LED tester on pins 86 and 85 fails to light up, check the fuses in the front SAM. If the fuse for the fuel pump relay is good (F43 for an E55 but maybe not for your car), you're going to need to check for continuity (connection end-to-end) between motor electronics and pin 86 (pull connector from the motor electronics before doing so) and *also* check to see if that wire is shorted to ground; in this case should be easy to find as a burnt fuse. FWIW, I once had a shorted wire for which I failed to check (duh!) and spent literally ~$600 replacing parts only to find a shorted pin from a connector where the plastic deformed from pressure being pushed against a chassis weld for ~16 years. Literally no cost and 15 minutes of my time to repair after I spent hundreds of dollars looking for a shortcut to fix it. Be patient and search carefully. Time is money. Spend the time and not "time *and* money" throwing parts at the car. Been there, done that, got the T-shirt.

Go here for a good fuse and relay listing:
http://kropf.net/w211/W211fuses.pdf

Post your VIN and when I get a break from work, I'll look up the schematic for your car and let you know which fuses/relays at which you should be looking. There are multiple harnesses on the W211 so it is best to look it up by VIN.

Good luck to ya.

 

Thanks so much for your help, I do think it is some kind of wiring/electrical problem. I will try to do the steps you suggested tonight.

I do think it has something to do with the fuel pressure sensor. I will be very interested in seeing the schematic as I really want to understand what the other wires on the fuel pump harness are connected to as my suspicion is some kind of short. (as you eluded to above). I have also thrown a fair amount of money at this already. One cheap sending unit and then a brand new VDO. Crank shaft position sensor, MAF etc.... They probably needed to be replaced anyway, but would like to have not spent the money :-(

In the mean time, here is my VIN: WDBUF65J73A121500

Thanks again and I will report back