Fuel Data Computer Error

[tkswan]

02 LSV8. 174k miles.

Today it threw a Fuel Data Computer Error on the computer readout and the fuel gauge parked at E as if the engine was off. I am sure I have over 1/2 tank of gas. Suggestions?

[shorod]

Sounds like the level sensor may be faulty. The code may have been set due to the rapid decrease in level versus normal fuel flow rate. I trust you checked for a fuel leak.

-Rod

[joegr]

Originally Posted by shorod

Sounds like the level sensor may be faulty. The code may have been set due to the rapid decrease in level versus normal fuel flow rate. I trust you checked for a fuel leak.

-Rod

Just to elaborate a little bit. There are two fuel level senders (left side and right side). One of them has failed. A good scan tool will return a code indicating which one of the two is the problem.

The right side fuel sender is a part of the electric fuel pump assembly.
The left side one is a part of the jet pump assembly.
You can access both assemblies with the fuel tank still in the car (and with fuel in the tank). You remove the rear seat bottom cushion to get to them.

[tkswan]

Rod, No fuel leaks.

I also have a CEL-P0460 - "Fuel Level Sensor A Ckt Malfunction".

I will make sure there are no blown fuses.

Joegr, So I need to figure out which one is bad and then change it out via the fuel pump access under the seats. Ive replaced the electronic fuel pump so i know exactly what to do...I think

Lots of lessons learned about properly re seating that big green ring. I will need to buy that special tool.

Additionally, The (driver side) jet pump level sensor is a separate assembly. The (passenger side) electronic pump, the level sensor is part of the pump. So if its the electronic side sensor that's bad, I have to replace the whole pump. Geez!

Got it.

[joegr]

I think that P0460 is the driver's side sender, but I am not 100% certain about it.

[shorod]

Are you certain on the P0460? I entered the factory service manual for the 2002 Lincoln LS and P0460 is for the fuel level sensor, but it does not specify between sensor A or B. The manual refers the reader to the instrument cluster section (413-01) for the LS (and a few other models) but that section does not appear to refer to a P0460. I'm not sure what to tell you.

-Rod

[joegr]

My listing shows it as fuel sensor A. It's just that I'm not 100% sure that sensor A is the left side.

You need the emissions diagnosis manual from Ford for codes like P0460.

[shorod]

Yep, I've got the emissions diagnosis manual on the service manual DVD, but that section points to the instrument cluster diagnostics sensor for a P0460 on the LS.

My expectation would be sensor A is on the main pump side, and sensor B would be for the jet pump side.

-Rod

[tkswan]

Yea, the ODBII readout says Sensor A. How do I figure out which side is which? The electronic pump has the sensor attached. That pump was replaced about a year ago.

[joegr]

Pull the back seat cushion and disconnect the electrical connectors at both pumps. Then measure the resistance of each sender.

The normal operating range of the fuel delivery (electric pump) module sender is from 16 ± 2 ohms at empty (E) to 155 ± 4 ohms at full (F). The normal operating range of the jet pump module is from 19 ± 2 ohms at empty (E) to 160 ± 2 ohms at full (F).

On the driver's side, it's the white/red and brown/red wires that you measure across. On the passenger side, it's the white/blue and the brown/blue wires.

[tkswan]

Rod, Joegr. Check out the attachment (image). I got this from the dealership. The parts guy seemed confident that the A sensor is the mechanical pump. The attachment indicates that the jet pump is the B sensor becasue it has a triangle pointing to it. see the legend in the upper left of the image.

Let me know what you think about this.

[joegr]

I don't know if it works that way. (If the suffixes on part numbers match up with the A and B codes and so on.) If you just measure the resistances of the senders (without removing them) you can eliminate all doubt.

[shorod]

I agree with Joegr. You'll gain access to both when you remove the seat cushion, so take some measurements and see what makes sense.

-Rod

[tkswan]

I pulled the seat cushion out and unplugged the electrical connectors on the pumps. There is a mismatch in wires and wire colors.

The Jet pump has only two connection leads. (yellow, orange)
The electrical pump has four connection leads. (red, red with black stripe, yellow, orange)

Is it because the level sender on the jet pump [IS NOT] attached to the pump, while the level sender on the electrical pump [IS] attached to the pump.

[joegr]

Those are the colors of the wires going to the connectors on the car side of things, not the colors on the pump sender assemblies. On the passenger side, just match up the colors from the car's harness to whatever color wires they connect to on the pump side. On the driver's side, it doesn't matter because there are only two wires.

I don't think you understand the jet pump. It is hydraulically powered from the flow of fuel from the electric pump on the passenger side. It has no electrical connections, so the only connections to the driver's side jet pump assembly are for the fuel level sender.