? - Location of Fuel Level Sensor "B"

[Casey388]

Hey everyone. I finally got my 2010 MKS Eco running and found that the fuel gauge isn't working. It is stuck right at 50% all the time. I checked the codes and I had a P2068 - Fuel Level Sensor "B" Circuit High code. Any idea where this sensor is located? I was thinking it is in the sending unit on the driver's side of the tank, but I wanted to make sure before I tear it apart.

Thanks for your help!

 

[Ta2dResqr]

Might be a sensor but the definition from that code is "Sets in the PCM when the PCM detects an open or short to voltage on the fuel level sensor circuit on the messaged input received from the IPC (Instrument Panel Cluster)." Possible causes are Communication link concern, Damaged instrument panel cluster, damaged instrument cluster, or Damaged PCM. If the IPC detects an issue with one of the fuel level senders, it is supposed to default to E, not 1/2. P0460 should be sensor A and P1346 should be sensor B if one of the sensors themselves had an issue (A being the pump module and B being the transfer side).

 

[Casey388]

Dang so it is sounding more like a PCM issue. I have been using my Bluedriver OBD2 scanner, looks like it might be time to bring out the Forscan.

 

[Casey388]

It looks like the Bluedriver couldn't connect to all the modules. Once I hooked up the Forscan and did a reset, once I restarted the car I saw the P1346. Going to try and replace the sensor behind the driver's seat in the tank and see if that fixes the issue.

 

[jman1200]

Is it at 50% with a full tank or just stuck there?
When I was troubleshooting an issue, I played a bit with the tank fuel pump, sender and their connections.
I now know that there are two fuel level senders and the fuel gauge gets a signal from each and displays the average. Because of the drive shaft, the SHO has a saddle fuel tank so it has a level sender on each side.
Since I'm not sure which one is B, I'd remove the rear bench and disconnect one side at a time and observe which one doesn't have any effect on the fuel gauge, that should be the bad one.
There are some pics here.

 

[Casey388]

Is it at 50% with a full tank or just stuck there?
When I was troubleshooting an issue, I played a bit with the tank fuel pump, sender and their connections.
I now know that there are two fuel level senders and the fuel gauge gets a signal from each and displays the average. Because of the drive shaft, the SHO has a saddle fuel tank so it has a level sender on each side.
Since I'm not sure which one is B, I'd remove the rear bench and disconnect one side at a time and observe which one doesn't have any effect on the fuel gauge, that should be the bad one.
There are some pics here.

Great point. I have kept the tank as close to full as possible (filling it every 75-100 miles) to make sure I don't run out since I didn't trust the gauge. I am going to try to unplug them and see which one is causing the issue. Luckily I ordered the parts yesterday so just waiting for a break in the rain and then I will knock it out.

 

[Ta2dResqr]

P1346 should have 2 options.
P1346:11 -
C3 CHECK THE FUEL SENSOR FOR A SHORT TO GROUND


- Disconnect: Fuel Pump Module C463 (DTC P0460:11) or Fuel Level Sensor C434 (DTC P1346:11).
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IPC Self-Test.
- NOTE: DTC P0460:11 or P1346:11 may also be present.
- Repeat the IPC on-demand self-test.
- Is DTC P0460:13 or P1346:13 retrieved?

Yes
INSTALL a new fuel pump module (DTC P0460:11) or fuel level sensor (DTC P1346:11). REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.

No
GO to C4.

or P1346:13 -
C11 CHECK THE FUEL LEVEL SENSOR CIRCUITRY FOR AN OPEN


- Disconnect: Fuel Level Sensor C3270.
- Connect a fused jumper wire between the fuel level sensor C3270-2, circuit VMC23 (GN/OG), harness side and the fuel level sensor C3270-1, circuit RMC33 (WH/VT), harness side.
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IPC Self-Test.
- NOTE: DTC P1346:13 may also be present when carrying out this step and should be ignored at this time.
- Repeat the IPC self-test.
- Retrieve the IPC continuous DTCs.
- Is DTC P1346:11 retrieved?
Yes
REMOVE the jumper wire. INSTALL a new fuel level sensor. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.
No
REMOVE the jumper wire. GO to C12.

Hope that helps. Bad news is like I said before, with bad sensors, the car is SUPPOSED to default to E.

 

[Casey388]

I thought it might be a good idea to clean out all the connections with electronic cleaner and I should have just left it alone. @jman1200 I saw your post about the issues you were having with the fuel pressure sensor connector and now my connector won't latch on. Looks like I will have to take the vacuum and a toothbrush to clean up the connectors so they will go back together.

The lock ring for the Fuel Sender Unit is rusted in place so I am waiting for my lock ring tool to come in the mail on Monday then I will try switching out the fuel level sensor.

EDIT: I forgot to add, I disconnected both level sensors and it didn't matter which one was unplugged, the fuel gauge went to half. I did perform an IPC Module reset and saw the fuel gauge sweep from empty to full, then go right back to half way.

 

[luigisho]

I had a fuel level gage/sending unit issue in my '14 f150. I used 2 treatments of techron concentrate (or whatever the most concentrated one is they sell at the auto box stores) in the fuel tank over a tank or 2 of fuel and that cleaned whatever was built up on the sending unit. Reads correct for over 18 months now. If you have easy access, which I did not, maybe physically removing and cleaning or replacing is more desirable. I tried to not drop the tank in mine.

 

[Bluezone]

How are the ground points?

 

[SeanDev]

Bluezone brought up a good point, on fuel level sending, module, and transfer, they use a common ground. Other option is to go ahead and replace fuel sending unit as it's not reading, the float is either hung up or the electrical compontens are failing on the unit. I replaced my LPFP fuel pump when I did the deutschworks upgrade. Not fun, alot of cussing, bruises and cuts. That vape line under the top was created by Satan. And it might not be a bad idea to get in there. even with my SHO at only 52,000 miles now that filter was black as night. Unfortunately the top side of tank is exposed in a sort of way, front of tank is open space to outside, recommend cleaning everything off around unit, before attempting, if you do. I had mouse SHIT on my fuel unit.

 

[jman1200]

I thought it might be a good idea to clean out all the connections with electronic cleaner and I should have just left it alone. @jman1200 I saw your post about the issues you were having with the fuel pressure sensor connector and now my connector won't latch on.

Read where I wrote about the inner gasket of that connector. If not seated properly it won't let you latch the plug.

 

[Casey388]

Read where I wrote about the inner gasket of that connector. If not seated properly it won't let you latch the plug.

I tried pushing that in but it didn't make a difference. I think by that point I moved the pins and that is what is hitting now. So I gotta figure out how to move them back in the correct position.
Finally got my fuel pump ring tool today and it made quick work of taking off the ring. I pulled out the fuel sender on the driver's side and found the issue. There is a yellow/orangish colored pipe that the fuel level sensor connects to. That pipe had broke off the bottom of the fuel sender cap that the ring holds in place at the top of the fuel tank. So the fuel level sender was just floating in the middle of the fuel tank. I am going to see if I can get a new pipe or if I have to get the whole unit. Guessing I will have to get the whole unit. I put it back together and it looks like it is working but that pipe was clearly broke and it is just a matter of hitting a big enough bump for it to fall off again.

 

[jman1200]

IIRC that whole sender unit wasn't that expensive.

Got pics?

 

[Casey388]

I looked around at all the junkyards and none of them had the correct fuel-sending unit. From Ford, it was a little over $100 for it. I ended up finding an aftermarket unit for $50 on eBay. It ended up working perfectly and was installed in a matter of 15 minutes. I was worried I would need a fuel line disconnect tool and could undo the clip by pressing it together and pushing it through. The only tricky part was keeping the O-Ring on the sending unit and putting everything back together. I just got back from the gas station and it is finally able to read a full tank and the code has gone away.

Attached is a photo of the broken piece and a picture of the new aftermarket sending unit.
New Sending Unit:


Broken Unit:


@jman1200 The o-ring on the fuel pressure sensor was the reason why I was unable to plug the 3 wire connector into the sensor, just like you said. I tried pushing it back as much as possible with a small flat head and it didn't make a difference. Couldn't get it pushed in no matter how hard I tried. I ended up getting the flat head under the o-ring and pulled it out. Then I was able to get it plugged in correctly.