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Code P1431, Gas Gauge going to Empty, Low Fuel Light coming On, after 70 miles after Fill Up

drseth

Member
Joined
Apr 6, 2014
Messages
11
Location
Moon, VA
Corvette
2001 Yellow Corvette Coupe 6 spd
Hi,

My 2001 Corvette, which has 60K miles, has been having this DTC P1431 coming on about 60-80 miles after each fill up. I have read other posts about Chevron Techron additive, adding the stuff after each fill up (4 large bottles total), and have taken the car to the dealer and had the BG injector service done. The Code is still coming on, with the gauge going to empty. I have even added Lucas gas treatment, to no avail.

On fill up, The gauge points to the notch below Full, and after I reset the code, I have had the code come on again . The dealership decided that I need a new right side sender/fuel pump assembly and wants $983 for the job, which includes 3 hours of labor.

I found an AC Delco MU1218 right side fuel pump with Sensor, same as the dealership, for under $200.00, with free shipping. I think I am going to get a local shop to install it for me. With 3 hours at $75 per hour, I figure to come out $425 poorer, instead of almost $1000 the Stealership wants. If I had a lift, I would be tempted to try it myself.

Any thoughts on this?
 
I agree with what you plan based on what you have provided. Might just need a good cleaning but if it were me once I pulled it I would put in a new one.

The part number is correct and the part price is fair. Not thinking it is a 3 hour job since you don't need to drop the tank. I assume he will charge you the time it takes.
 
I agree with what you plan based on what you have provided. Might just need a good cleaning but if it were me once I pulled it I would put in a new one.

The part number is correct and the part price is fair. Not thinking it is a 3 hour job since you don't need to drop the tank. I assume he will charge you the time it takes.

Is there a procedure to do this available online? I saw where a guy removed the RR tire and removed a plate to access the top of the tank. Can the sender be replaced through that opening?


Any help would be appreciated.

Seth Anderson
Moon, VA
2001 C5 Coupe 6M
 
Yes, Big Picture you just have to remove the RR tire, remove the access cover and drain the tank. The sender is at the tank bottom. We can get you all the details if you decide to do try it yourself. I have the FSM instructions. I will try and find where someone has done it and provided some guidance. They could be a resource to discuss their DIY.

PS: Does the mechanic you mentioned have access to the FSM guidance?
 
Do not assume that solving this code is as simple as replacing the right tank sender/pump assembly. There are several reasons the code could be setting. Some are: a failed tank sender, a failed siphon jet, a problem with the tank crossover assembly, a problem with wiring and connections or a problem with the PCM. I recommend you, first, diagnose the problem using the instructions in the Factory Service Manual before you start buying parts because of the amount of labor involved in pulling the tank. To diagnose, you need the FSM, a DMM and likely a scan tester.

Pulling a tank to change the sender can be a DIY job if have some experience working on fuel systems of late model vehicles, you consider yourself an intermediate-level technician and you have the Factory Service Manual. Also, the job likely requires draining the fuel tanks so you'll need the equipment to do that and a safe container in which to store the fuel.

Good luck.
 
I agree with Hib it might be something else but the sender is most likely in my mind (which wanders a lot). If you want to try the full diagnostics we can go down that road if you think you can do it from your end. I have helped 2 others with similar issues on the right sender (one guy was in Germany but at least he had good English since my German is not so good anymore). They both resolved their issues by replacing the senders. You don't have a 2004 so you don't have to pull the tank thank goodness.

While you think about it I found a video on how to replace the right side sender. Have not watched it completely yet but I have seen other things he has done and they provided good guidance. If you end up wanting to do this yourself I will watch the whole thing and give you feedback on anything that needs to be clarified in my wandering mind. Guten Tag, Mr. Sam

How to change the fuel sending unit on your Corvette! With briansmobile1 Code P2068 - YouTube
 
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The dealership checked things with their scanner tool, which is more detailed than the DIC, and they said I needed a right tank sending unit, but they quoted the entire fuel pump with sending unit. I have instructions on ALLDATA, but I have read that from 1997 to early 2003, the fuel pump/sender can be changed without removing the tank. I would like to hear from someone who has changed their fuel pump/sender without removing the tank.
 
Keep in mind that the video linked above is for a C6 which has a somewhat different fuel system than a 97-03.5 C5.

Good luck with the project.
 
Sorry about the video being a C6. Like I said, I just watched the start.

The FSM does not require the tank to be dropped in 2001. I looked at the 2001 FSM to respond to you. If you want to talk to someone who has done it before then do a search and contact them. Like I said, there are at least 2 Threads on the Forum here.

Good luck.
 
Have you tried a good fuel system cleaner yet?

Sometimes this works and there is no need to change the sending unit.

I like BG 44K and use it annually just to keep things clean.
BG 44K® Fuel System Cleaner | BG Products, Inc.

I have had the dealer do the BG injector service, along with their fuel system cleaner. I have also used Chevron Techron and Lucas Gas Treatment, all to no avail.

I probably could have used Snake Oil and have it work better. Maybe it is too far gone for the gas tank additives to work. I bought an AC-Delco right side Fuel pump with sensor for under $200 on Amazon, and I think I am going to be like O. J. Simpson and take a stab at it!!!

Looks like all I have to do is jack up the RR, remove the tire, remove the inner fender, and unhook the wires and hoses. Then the whole assembly comes out through the inner fender cover.

If any of you know any better, let me know.
 
Maybe it is too far gone for the gas tank additives to work.
Maybe so.

Years ago, our '98 had a similar problem and had to have the fuel pump/sender replaced - under warranty thankfully. After that, I've regularly used BG 44K in all my cars just avoid the issue happening again. Seems to have worked for me.
 
The fuel pump/sender came today, fresh from Amazon.com. I guess it is time to start wrenching.
 
Replaced Right Tank Pump with Sending Unit

UPS dropped the new pump, so I went ahead and decided to tackle it myself. I was really surprised at how easy it actually was.

1. Disconnect battery

2. Remove Left side coil cover and depressurize the fuel system. The fuel rail has a screw off cap with a Schrader valve, like on tire valve stems.

3. Jack Right Rear, remove wheel.

4. Remove the 10 or so 7mm screws that hold the inner fender cover and remove.

5. Remove a 10mm nut and a 12mm bolt holding the rear part of the fuel tank shield.

6. Uncap the two fuel lines, disconnect the wire connector, and the 6 7mm screws holding the pump housing from the tank.

7. Remove fuel pump/sender

8. Install new fuel pump/sender using new shear off screws included with fuel pump/sender

9. Replace fuel tank shield, inner fender, wheel, and reconnect battery.

10. Turn key to On position, but do not start for 10 seconds, check for leaks.

Here are a some photos I took myself. My hands were so grimy I wasn't able to take more photos.

IMG_20140501_172539.jpgIMG_20140501_172547.jpg

I spent some time looking at the sender part. I scraped some of the deposits off of the contacts and checked it with a multimeter. Before cleaning, it read very erratic, but after cleaning it worked as new. In hindsight, maybe a good cleaning of the metal contacts is all that is needed with some emery cloth. It took me about 3 hours total, which was the same time the dealership estimated. It would have been less if I had less gas in the tank. I had to drain 4 gallons of gas that was still in the tank.

IMG_20140501_194657.jpgIMG_20140501_194730.jpg
 
if you continue to fill the tank after the station pump shuts stop doing this as it is moving the slider into unused area causing the problem. I found this out with my 97. once I stopped force feeding the tank after the station pump shut off I had no more fuel gauge problem. I also has a 1999,2002,2005 and a 2008 and never had this problem again
 
I've had the erratic gas gauge issue for years. Tried techron and other products when the tank was at 1/4 full or so and would still get the Empty tank on my gauge/Check Fuel level messages. Yesterday the DTC 1431 appeared. I filled the tank at the nearest gas station and the gauge read full again, and the Check Engine disappeared. When I got home I used my scan tool and cleared the DTC. Drove about 60 miles and all is working for now.

Anyhow, have you had any fuel gauge issues since installing the new right rear sending unit? You also mentioned, and I saw your photos above, that you might have gotten away with cleaning the contacts on the old sending unit instead of replacing it with a new unit. However, I'd hate to spend the time pulling the sending unit, cleaning the contacts, and reusing it only to have the same problem reoccur again. What would you advise?

Any other tips or tricks I should be aware of when attempting this project?
Thank you!!!
 
I've had the erratic gas gauge issue for years. Tried techron and other products when the tank was at 1/4 full or so and would still get the Empty tank on my gauge/Check Fuel level messages. Yesterday the DTC 1431 appeared. I filled the tank at the nearest gas station and the gauge read full again, and the Check Engine disappeared. When I got home I used my scan tool and cleared the DTC. Drove about 60 miles and all is working for now.

Anyhow, have you had any fuel gauge issues since installing the new right rear sending unit? You also mentioned, and I saw your photos above, that you might have gotten away with cleaning the contacts on the old sending unit instead of replacing it with a new unit. However, I'd hate to spend the time pulling the sending unit, cleaning the contacts, and reusing it only to have the same problem reoccur again. What would you advise?

Any other tips or tricks I should be aware of when attempting this project?
Thank you!!!

Glad you got it figured out. After about 6 months, the gas gauge reads full at 7/8's of a tank, and sometimes the code started popping up from time to time.

The Techron only works when bathed on the right side sending unit, which is empty if there is less than half of a tank. The tank needs to be at least full to just above half tank for the stuff to work on the right side, since it feeds off the right side first, then the left side for the bottom half of a tank.
 
Replaced Right Tank Pump with Sending Unit

UPS dropped the new pump, so I went ahead and decided to tackle it myself. I was really surprised at how easy it actually was.

1. Disconnect battery

2. Remove Left side coil cover and depressurize the fuel system. The fuel rail has a screw off cap with a Schrader valve, like on tire valve stems.

3. Jack Right Rear, remove wheel.

4. Remove the 10 or so 7mm screws that hold the inner fender cover and remove.

5. Remove a 10mm nut and a 12mm bolt holding the rear part of the fuel tank shield.

6. Uncap the two fuel lines, disconnect the wire connector, and the 6 7mm screws holding the pump housing from the tank.

7. Remove fuel pump/sender

8. Install new fuel pump/sender using new shear off screws included with fuel pump/sender

9. Replace fuel tank shield, inner fender, wheel, and reconnect battery.

10. Turn key to On position, but do not start for 10 seconds, check for leaks.

Here are a some photos I took myself. My hands were so grimy I wasn't able to take more photos.

View attachment 18528View attachment 18530

I spent some time looking at the sender part. I scraped some of the deposits off of the contacts and checked it with a multimeter. Before cleaning, it read very erratic, but after cleaning it worked as new. In hindsight, maybe a good cleaning of the metal contacts is all that is needed with some emery cloth. It took me about 3 hours total, which was the same time the dealership estimated. It would have been less if I had less gas in the tank. I had to drain 4 gallons of gas that was still in the tank.

View attachment 18529View attachment 18531
Thanks for the instructions. I'm going to try it this weekend on my 01
 
My 2003 C-5 has 2 tanks 2 pumps & 2 float assembly's , there is a cross over tube tank to tank
Hib Halverson has some good tech tips also

GM Parts had only one side pump/float in stock cost near $1K for it no other stock available in the future
 
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