Fuel Gauge Problem

[shangapol]

Hello Enthusiast

These last few days my fuel gauge went crazy. suddenly, indicating that I have half a tank and in a blink indicates that I have no gas and suddenly begins to rise the fuel level and back down again.:iono::confused:

WTF?? Please Help me with this. :frown::smile:

[CTScott]

The fuel sender uses a resistive strip for determining the fuel level. The picture below shows one remove from the tank. Contaminants in the fuel can cause the issues you are seeing. Sometimes the issue will fix itself (after 20 or so cycles of the gas tank). You can pull the sender assembly and try cleaning the resistive strip with electronic contact cleaner.

42518

[shangapol]

Ok, Very good idea but, How I go There??

[CTScott]

Take a look at the "Fuel" section of the repair manual. The access panel for the top of the tank is under the rear seat.

http://www.etimago.com/yaris/repairmanual/

[mazilla]

Take a look at the "Fuel" section of the repair manual. The access panel for the top of the tank is under the rear seat.

http://www.etimago.com/yaris/repairmanual/


Where would one get that tool to remove the retaining ring? I'd like to give this a whirl since my gauge is also malfuntioning. Like most of the others it now shows two bars when it's actually empty...I've gotten pretty close to forgetting to fill up a few times already.

[CTScott]

Where would one get that tool to remove the retaining ring? I'd like to give this a whirl since my gauge is also malfuntioning. Like most of the others it now shows two bars when it's actually empty...I've gotten pretty close to forgetting to fill up a few times already.

The SST is a Toyota tool, so you could probably order it from the dealer for a handful of cash. I used a dead-blow hammer and a piece of oak to spin mine off, when I removed Crashy's.

[othater]

The fuel sender uses a resistive strip for determining the fuel level. The picture below shows one remove from the tank. Contaminants in the fuel can cause the issues you are seeing. Sometimes the issue will fix itself (after 20 or so cycles of the gas tank). You can pull the sender assembly and try cleaning the resistive strip with electronic contact cleaner.

42518

CTScott,

1) On cleaning the resistive strip.
Whats you opinion on using fuel cleaner, Redline in the gas tank to possibly clean the strip.
2) I replied to another thread where the person reset the ECU. Would that re-learn the gas sender to gas bars?

Thank you for your knowledge.

[CTScott]

CTScott,

1) On cleaning the resistive strip.
Whats you opinion on using fuel cleaner, Redline in the gas tank to possibly clean the strip.
2) I replied to another thread where the person reset the ECU. Would that re-learn the gas sender to gas bars?

Thank you for your knowledge.



I am not sure about if fuel system cleaner will help or not. I have a gut feeling that it will considering that I had a Subaru that had a fuel gauge issue, which eventually healed itself.

Resetting the ECM will not help, since the ECM doesn't see the fuel sender, just the cluster ECU does. You can try disconnecting the battery to reset it, but it actually reinitializes the fuel level every time you shut the car off.

[othater]

Thank you for the quick reply CTScott.
What about running high octane.
I think I'll try that with the cleaner.
I will try fuel cleaner on the next couple of fill ups and report back.

[CTScott]

Thank you for the quick reply CTScott.
What about running high octane.
I think I'll try that with the cleaner.
I will try fuel cleaner on the next couple of fill ups and report back.

From the other thread, I take it you are having the issue where you run out with a couple of bars still showing on the gauge?

[Bluevitz-rs]

Not sure it related or if I'm just posting useless babble, but once in a blue moon my fuel gauge will take almost 10 minutes to go from empty to full after a fillup. Even if I turn the car off, it'll be at the last spot it left off when I turn it back on. I have the '05 HB with tach and digital fuel gauge.

[CTScott]

Not sure it related or if I'm just posting useless babble, but once in a blue moon my fuel gauge will take almost 10 minutes to go from empty to full after a fillup. Even if I turn the car off, it'll be at the last spot it left off when I turn it back on. I have the '05 HB with tach and digital fuel gauge.

How the cluster ECU deals with the raw data from the sender is a bit of a mystery.

I have done much experimentation and I can watch the raw input value (0-255) from the Cluster ECU on my YarGauge and see it go from 13 with the tank full (it actually hits that value at 11.2 gallons and then stays at that value until gas overflows the filler) to 211 at empty (there again, it hits that value with 2.41 gallons left in the tank, and remains at that value until the engine sputters).

Watching the value while driving is interesting, particularly with the tank at 1/3 full or less, as with the lack of baffling, the value swings +/- 2 to 3 gallons. So, the cluster ECU has to do some serious filtering to figure out what to display while in motion.

[Bluevitz-rs]

I guess it just takes the average value over a set time.

I'm starting to think if a weak battery might have caused it to do this. I've certainly never run out of gas with a 1/4 tank still showing. On my cluster the last bar flashes as the fuel warning. There's no extra light that turns on. And when it does flash, I'll usually put in between 44-43L the tank is 45L according to the manual.

[othater]

From the other thread, I take it you are having the issue where you run out with a couple of bars still showing on the gauge?

Yes, It's happen twice.
I've read a few different threads on this problem and looking for a
possible solution before actually having to replace the fuel pump.

[CTScott]

Yes, It's happen twice.
I've read a few different threads on this problem and looking for a
possible solution before actually having to replace the fuel pump.

Do you have access to a multimeter? With one you can check out the fuel sender from the connector on the instrument cluster.

[othater]

Yes I do have a digital multi-meter.
If you direct me to which connecter and what I should be reading.
Pull the instrument cluster out and measure across the connector. volts, ohms?
battery connected or disconnected.
full tank or when it get close to the two bars or both.
Sorry for all the questions.

[CTScott]

Yes I do have a digital multi-meter.
If you direct me to which connecter and what I should be reading.
Pull the instrument cluster out and measure across the connector. volts, ohms?
battery connected or disconnected.
full tank or when it get close to the two bars or both.
Sorry for all the questions.

Ohms, battery connected is fine, but ignition off.

Pull the right side connector from the cluster and measure the resistance of the violet wire on pin 3 of the right side connector of the cluster (black wire in pin 1, blue in pin 2, and then the violet is pin 3). Put one lead on the violet wire and the other on ground (you can either touch the metal frame under the dash for ground or can use the brown wire on the opposite end of the connector from the violet one).

The resistance goes from 13.5 ohms with a full tank to 414 ohms with and empty tank. If the tank is half full you can have someone else rock the car side to side while you are taking the measurement to see a wide part of the range. Typically a fuel sender that needs cleaning will have a stretch that reads as open (as if the two leads are not touching anything).

[wajeehr]

Where would one get that tool to remove the retaining ring? I'd like to give this a whirl since my gauge is also malfuntioning. Like most of the others it now shows two bars when it's actually empty...I've gotten pretty close to forgetting to fill up a few times already.


I am also having exactly a similar problem like yours these days ..
can you tell me how you solved it ?
Thanks

[wajeehr]

Hello people
i am also having a similar problem these days with my yaris ..
can anybody tell me what is the definite solution ??

[CTScott]

Hello people
i am also having a similar problem these days with my yaris ..
can anybody tell me what is the definite solution ??

The only definite solution is to replace the fuse sender. If you are interested I have one for sale For $25 + shipping on my part-out thread:

http://www.yarisworld.com/forums/showthread.php?t=46798

[goosefraba]

Fellows,

My 2012 SE's fuel gauge is not right. It started off by dropping to the low fuel light from 3/4 tank within a 20 minutes span... kept there for a couple days... then jumped to full after filling the tank... wandered a bit then popped up to full... stayed on full for 180 miles, then dropped to the low fuel light. Interestingly, the "range" display in miles computed accurately at one point with the Trip meter for a while, but jumped to back to wacky. I guess it will periodically take a tank reading in the computation? Last night, the gauge moved from fuel light and is now reading 1/4 tank steady (110 miles on tank, so the reading is still wrong).

I am out of warranty so would like to fix this myself. Do you recommend replacing the sender first? If replacing the sender, does the sender unit itself pop out of the pump/filter assembly, and does the wire pair connector pop out as well = meaning easy? I have a good idea what it takes to remove the assembly from the tank, but want to make sure there are no gotchas.

Are there fuses to try or would you recommend running diagnostics from the harness connector that plugs into the instrument cluster (which CTScott described which wires/pins to check ohms in a fuel gauge thread).

One problem is that I do not have a service manual and do formal instructions of how to remove the rear seat properly and how to get to the gauge cluster without possibly breaking stuff!! It seems to me that the service/repair manuals are not very available. Do you know a good source for a manual?
Thanks

[CTScott]

Fellows,

My 2012 SE's fuel gauge is not right. It started off by dropping to the low fuel light from 3/4 tank within a 20 minutes span... kept there for a couple days... then jumped to full after filling the tank... wandered a bit then popped up to full... stayed on full for 180 miles, then dropped to the low fuel light. Interestingly, the "range" display in miles computed accurately at one point with the Trip meter for a while, but jumped to back to wacky. I guess it will periodically take a tank reading in the computation? Last night, the gauge moved from fuel light and is now reading 1/4 tank steady (110 miles on tank, so the reading is still wrong).

I am out of warranty so would like to fix this myself. Do you recommend replacing the sender first? If replacing the sender, does the sender unit itself pop out of the pump/filter assembly, and does the wire pair connector pop out as well = meaning easy? I have a good idea what it takes to remove the assembly from the tank, but want to make sure there are no gotchas.

Are there fuses to try or would you recommend running diagnostics from the harness connector that plugs into the instrument cluster (which CTScott described which wires/pins to check ohms in a fuel gauge thread).

One problem is that I do not have a service manual and do formal instructions of how to remove the rear seat properly and how to get to the gauge cluster without possibly breaking stuff!! It seems to me that the service/repair manuals are not very available. Do you know a good source for a manual?
Thanks

For your 3rd gen:

Once you get into the connector for the cluster, the fuel gauge comes in on the green wire in pin 16 of the 40 pin connector. There is a blue wire next to it in pin 17 and a brown wire on the opposite side of it in pin 14.

Looking at the connector from the back side where the wires come in and with the connector latch up:

20........1
40........21

If you unplug the connector from the cluster you can measure the resistance on the green wire (put one meter lead on it and the other on a chassis ground or any wire that is white with a black stripe).

The resistance with vary based on the fuel level and I believe that the 3rd gen uses the same sender as the 2nd gen, where the resistance goes from 13.5 ohms with a full tank to 414 ohms when empty.

If your fuel sender has a bad section, you will likely see a very high or open circuit reading when it drops from 3/4 to empty on you.

To remove the cluster you just pull the trim around it off with your finger tips. Once that is off just remove the mounting screws to pull the cluster out.

[goosefraba]

Thanks CTScott. The instrument panel was a really easy remove.. just pulled the trim gently and slowly, removed the 2 screws, then tilted it out.

I got a reading of 0 ohms with gauge stuck on the full mark before taking the reading. 117 miles on tank, so clearly the sender is not giving the resistance within the 13.5 to 414 ohms. 117 miles is roughly 3.4ish gallons from full. It makes sense that 0 ohms would peg the needle to full mark if less ohms is full and more ohms is empty.

I am going to take another reading after the gauge needle moves and sticks again. It would be nice to have an actual number correlation to the gauge needle being anywhere between the full and empty marks.... but based on this I think I am pretty certain the sender is bad.

[CTScott]

Thanks CTScott. The instrument panel was a really easy remove.. just pulled the trim gently and slowly, removed the 2 screws, then tilted it out.

I got a reading of 0 ohms with gauge stuck on the full mark before taking the reading. 117 miles on tank, so clearly the sender is not giving the resistance within the 13.5 to 414 ohms. 117 miles is roughly 3.4ish gallons from full. It makes sense that 0 ohms would peg the needle to full mark if less ohms is full and more ohms is empty.

I am going to take another reading after the gauge needle moves and sticks again. It would be nice to have an actual number correlation to the gauge needle being anywhere between the full and empty marks.... but based on this I think I am pretty certain the sender is bad.

Lower resistance does equal more fuel, but its should not hit zero ohms, even when completely full.

[johannes]

Dear CTScott,

as I have found several posts concerning fuel pump problems, where you provided help: can you probably give me a hint how to get the pump out of a Yaris mk1 from 2000? My problem is shown in this thread:
http://www.yarisworld.com/forums/showthread.php?t=52565

Best regards, Johannes

[goosefraba]

Problem update: I replaced the fuel sender and the gauge appears to be working fine. It did take some time for the instrument cluster to reach the tank level and stabilize right after the repair (20 miles or so). I did add a couple gallons for observation and the gauge needle followed accordingly. I drove around some, then filled up again. I will continue to monitor it, but it looks like it will be a winner.

Thanks CTS for the help. I was able to order the part with confidence that it would fix the issue. I used the 2007 repair manual Fuel section for reference and for how to bleed the fuel pressure down before removing the pressured fuel line. I used a 2 legged wheel puller with a crescent wrench to turn the large plastic ring. I did so by positioning the legs such that they were between the fins of the plastic ring, then torqued the whole thing by one of the puller's legs with the crecent wrench. I did not use the puller as a puller. For re-installation of the ring it helped to index the beginning of thread of the ring with the beginning of the thread of the tank. Also it helps if the tank is more towards empty since the fuel pump assy floats up and has to be pushed and held down in position while starting re-threading the plastic ring.

[cavramopoulos]

hi everyone, i drive a 2012 yaris hatchback and i noticed that when i first bought the car when i shut it off the gas gauge automaically went down, however now 2.5 years later it stays in place until the car is locked. does anyone else have this problem and if so have you gotten it fixed?

[cavramopoulos]

also another question...I noticed when I first turn my key in the ignition and all my warning symbols come on, the low fuel symbol does not light up...is that normal? I purposely ran my car out of gas this morning and the light did not turn on when it has in the past when I have about 5 litres left.