Fuel gauge issue: Fixed
 

The fuel gauge on my 02 started to give inaccurate readings that started about 6 months ago. It would generally give lower fuel readings compared to what was actually in the tank. After driving for a while it would occasionally rebound back to normal but was still unreliable. I already kept track of my odometer with my daily commute but still wanted a functioning fuel gauge.

This seems to be a common issue but the repair options that I looked up were rarely followed up with successful results & the TSB for a faulty fuel gauge only applies to certain 99-00 4runners. Here's a list of the commonly suggested repairs:

1. Recalibrate fuel gauge:
Step 1. With the ignition switch in the OFF position, press and hold the trip reset button.
Step 2. Continue pressing the trip reset button while turning the ignition switch to the ON
position.
Step 3. Within 5 seconds of turning the ignition switch ON, release the trip switch, press the
trip switch 3 times, and on the third press hold the switch for 5 seconds. The buzzer
will sound for 1 second at 800 HZ.
Step 4.After the buzzer stops, release the trip switch.
Step 5. Press the trip switch one more time and hold for 5 seconds. Once more, the buzzer
will sound for 1 second at 800 HZ.
Step 6.The calibration process is completed.
NOTE:
If in the operation of step 6, the buzzer sounds higher than that of step 5, turn the
ignition switch to OFF position and repeat the setting procedure from step 2.
*(Recalibrating the fuel gauge didn't work for me but was worth a try since it's free.)*

2. Replace fuel sending unit:
The information I saw on replacing the fuel sending unit with positive results were mixed. Some of the repairs said that the job was done with used parts that tested good but many of them didn't specify if new OEM parts from a Toyota dealer vs amazon/ebay were used or if the job was done with new aftermarket parts which could be a variable in the outcome of this repair.

3. Replace fuel sending unit & suction tube:
This was one of the options the TSB recommended for addressing a faulty fuel gauge on certain 99-00 4runners. I thought it was interesting that the TSB suggested replacing the suction tube in addition to the sending unit. This made me wonder if the cases where only the sending unit was replaced with unsuccessful results might have been different if the suction tube was also replaced. Possibly due one or both of the electrical connectors on the fuel suction tube going bad.

4. Replace No. 3 circuit board:
This was the other option the TSB recommended. The TSB also recommends recalibrating the fuel gauge if the No. 3 circuit board is replaced.

5. Fuel pump/sending unit ground wire:
While I thought inspecting the ground wire for the fuel tank components would have been a good starting point, I didn't know where the ground points were & although I wasn't opposed to drilling a hole into my floor board to re-ground the wire, as some information suggested, I didn't want to do that as a first step because I wasn't sure if it was a definitive fix.


Even though the TSB didn't apply to my 02 4runner, using it as a guide seemed like a logical starting point. At first I was going to replace the No. 3 circuit board due to the mixed results I read about others having unsuccessful repairs replacing the sending unit but thankfully my Toyota parts guys talked me out of replacing the circuit board because he said he has never sold that part to the public or techs & suggested I try a new sending unit first especially since it was a lot cheaper than a new No. 3 circuit board.


What worked for me:
I decided to replace both the fuel sending unit & suction tube with new oem parts from cobbcountytoyota.com. A couple hundred miles since the repair & so far my fuel gauge has been working normally. It's possible that replacing just the sending unit with a new one could have worked but based on the limited info on successful repairs, I didn't want to risk having to drop the tank again. Not a difficult job but didn't want to get infused with the smell of fuel a 2nd time.

*See @mtbtim & @infamousRNR 's vid on replacing the fuel sending unit. Fuel Sending Unit Replacement - YouTube

Parts list for 01-02: Fuel tank is slightly different than 96-00.
Fuel sending unit: 83320-35620
Fuel suction tube assembly: 77203-35660
Included with the fuel suction tube:
1. Fuel suction tube gasket
2. Evap sensor/electrical connector
3. Evap sensor gasket & yellow clip
4. Electrical connector & gasket for fuel pump & sender unit
No. 3 circuit board: 83862-3D570-RP (confirmed by my Toyota parts guy)

Parts list for 99-00: Parts list the TSB for 99-00
Fuel sending unit: 83320-35590 (for 2.4L, 3.4L manual & auto)
Fuel suction tube assembly: 77203-35461 (also fits 1996-1998 2.4L, 3.4L manual & auto)
Included with the fuel suction tube:
1. Fuel suction tube gasket
2. Evap sensor/electrical connector
3. Evap sensor gasket & yellow clip
4. Electrical connector & gasket for fuel pump & sender unit
No. 3 circuit board: 83862-3D251-RP

*There is another fuel sending unit part number 83320-80331 that parts.toyota.com lists for 1996-1998 4runners in 2.4L, 3.4L manual & auto. My guess is that the sending unit pn from the 99-00 TSB is an updated pn & would fit 96-98 since the fuel suction tube is the same pn for those years.



Gas tank is out.
https://i.imgur.com/jdwNxB0.jpg

Empty space where the gas tank lives.
https://i.imgur.com/yGOARR6.jpg
https://i.imgur.com/p1GGRPc.jpg

Old sending unit & fuel suction tube (left) next to new parts (right) with the fuel pump transferred over.
https://i.imgur.com/iRpVrlY.jpg

2 JIS/phillips screws that hold the fuel sending unit to the suction tube. New sending unit doesn't come with screws. Old screws were reused.
https://i.imgur.com/lV7xjsV.jpg

New fuel suction tube with sending unit installed. Torque the 8 8mm bolts to 31inch/lbs in crossing pattern.
https://i.imgur.com/K7E8F1N.jpg

TSB fuel t4r 99-00: Fuel gauge inaccuracy
https://i.imgur.com/LKxybAT.jpg
https://i.imgur.com/7GUVYlI.jpg
https://i.imgur.com/zdqIvBO.jpg
https://i.imgur.com/QBfMXhJ.jpg

A frame that clean should be illegal

Has that thing ever been outside? Holy cleanliness!

Great post and one I will be using in the near future. I most likely have to get at the pump anyway as I have the hard start when warm problem and it may be the pump. Still need to troubleshoot this one.

Parts list for 99-00: Parts list the TSB for 99-00
Fuel sending unit: 83320-35590 (for 2.4L, 3.4L manual & auto)
Fuel suction tube assembly: 77203-35461 (also fits 1996-1998 2.4L, 3.4L manual & auto)
Included with the fuel suction tube:
1. Fuel suction tube gasket
2. Evap sensor/electrical connector
3. Evap sensor gasket & yellow clip
4. Electrical connector & gasket for fuel pump & sender unit
No. 3 circuit board: 83862-3D251-RP

This is Golden!! And timely, my 99 is doing some whacky fluctiation from cycle to cycle, NFG. I had hoped to tackle this during my week off next week, but I'm pretty sure I'll be bombed with projects. Still good to have all this info!

This was my first takeaway too :lol:
Never in 100 years would I have guessed you can calibrate the fuel pump like that. Learn something new every day here

I had this TSB performed at the dealer on my 99, the VIN fell into the do everything list, and they forgot to mention the P.A.N.T bulletin 00-01, and zeroed out my OD and made me sign off of the change, anyone have a copy of the PANT bulletin? it was pretty annoying to read this after the work was completed. And running out of fuel is a safety concern passed off as a TSB on the customers dime for those that got known faulty parts installed at the factory.

NO!!! The fuel sending unit is electrically different for the '96-'98 compared to the '99-'02. 2-wire vs. 3-wire. The later model gauge cluster is much more 'digital' and very different from the earlier style much more 'analog' gauges.

-Charlie

Big time different. +1 with phattyduck. Always think 96 to 98 almost always the same 99-00 hybrid 01 -02 almost always the same with anything electrical.

The gas tanks are even different from the early years to late model.

Also always best to verify things are the compatible and the same across the years if possible. :)

Sent from my SM-A505U using Tapatalk

Lol ok

@fourfive

How is the repair holding up now a little while later? The gauge in my 01 has been acting funny lately too. Typically I only see the issues at half a tank or lower, but the gauge will be at total empty when I start it and have the light on. After running for awhile it will rise back up to an accurate reading and the light goes off. It doesn't do it every time either though which is strange.

I've been reading about the fuel sending unit being some people's problems, one or two people saying the calibration fixed it, and then some people saying the ground wire fix solved their issue or they had a grounding issue in the rear of the truck with the taillights or trailer harness which is tied in for at least some years I guess.

I'd love it to be a simple fix that doesn't involve dropping the tank. I already did that once years ago when I replaced the fuel pump as preventative maintenance.

A little over 2,500 miles since the repair & my fuel gauge has still been working consistently. I can relate to wanting a simple repair without having to drop the gas tank because my main concern going into this was going though the work of removing the tank to replace parts & my fuel gauge still not working since I didn't test my sending unit or suction tube with a multimeter.

I generally try to troubleshoot before replacing parts but there were a couple reasons I didn't go through that process for this repair. The first was it would require dropping the tank for testing & I wanted to be more time efficient since the cost of parts weren't too bad. Also, I was pretty confident that replacing some or all the parts the TSB suggested would work. The second reason was since my fuel gauge issue was intermittent, I thought there was a chance I could get a false negative.

For anyone that has replaced the sending unit with a new part from toyota that is still having fuel gauge issues, I'd recommend replacing the suction tube assembly using new toyota parts. For me, in the event replacing those 2 parts didn't work, my plan was to replace the No. 3 circuit board in the dash gauge cluster. And if that didn't work, I was going to track down the ground point for the sending unit. Cost wise it would have made more sense to check the ground first & I probably would have done that if I didn't have the TSB to follow as a rough outline.

@fourfive

Thanks for this write up. Two weeks ago I ordered the fuel sending unit and suction tube assembly. I started dropping the tank and realized I never want to do that again so I stopped and went to get a new check valve that is only on the 01-02 4Runner and the rollover valve so everything would be fresh on the tank. I did the fuel pump a few years ago.

When the rest of the parts came in last week I finished the job. Those EVAP lines coming off the back of the tank are the worst, but I got them eventually. And that stupid connector on the check valve is frustrating also. I replaced that entire hose too out of an abundance of caution.

Anyway, thanks for this write up and your other one on the EVAP leak code you were getting. I used both for part number and picture references.

After replacing my suction tube assembly and sending unit my fuel gauge seems to be working normally again. It's only been about a quarter tank, but the 10 times or so I've started it since then it has immediately read accurately unlike what it was doing before.

I thought this was just a known issue with all of our 4Runners? lol

Neither the 97 I used to own, nor my current 96 have ever had an accurate fuel guage. Says I'm Empty (but no light) at like 150 miles, light never comes on til like 220 lol

I just reset my trip meter everytime I fill up and get gas around 200

great thread though, always love the large amount of pictures and focus on detail. Kudos to you sir :hatsoff:

Great to hear. The ribbed plastic evap hose is a rough one to disconnect. Not long after completing the repair I got a P0440 evap code. I looked over all the hoses to make sure they were fully connected & it turned out that the ribbed plastic evap hose wasn't fully seated on the gas tank end. Took some pushing force & twisting for it to click back in place but the evap code has since been gone. I'm just under 4,000 miles & my fuel gauge has still been good.

Tip for anyone having to drop their gas tank, remove the rear drive shaft for better access to the connections on top of the tank & while the drive shaft is off, remove the slip yoke to re-grease & grease the U joints since it will be easier to access the grease fittings.