Quick Update: some of you know that I was having a lot of problem when the gas gauge was not reading the gas level properly for the longest time the level was stuck at 3/4 no matter what, I brought the car to 2 infiniti they said paid $150 for diagnostic
the first one said to change the sending unit and fuel pump,
the second shop said they do not know the problem and are waiting for infiniti to send some for the fix and a lot of infiniti are having the same problem
I brought it to another local shop on Thursday and they did test the wiring and continuity, they even change the sending unit and fuel pump that I had bought on ebay and at the scrap but nothing. the mechanic had a software that he pays 200 a month and looked again and saw something called A/C amp. He said if we can get this part we can try if it work it work if not we will do more test. Unbelievably I took one from the 2010 g37x at Kenny u pull from Montreal couple of months ago, brought it to the shop at 5 AM and I took apart the center of the dash and connected the A/C amp and we started to do some test.

1- We took 2 other sending unit and fuel pump
2- both level from the sending unit and fuel pump were on empty
3- We turn the key to ON and the gas gauge on the cluster showed empty
4- We turned the car off
5- We took both level from the sending unit and fuel pump we raise to half a tank
6- We turned the key back to ON and the gas gauge showed half a tank and the mechanic was happy he said there you go it worked.
7-He said that sometime even experience mechanic would of never find that problem
8- He said to keep him up to date when the gas gauge goes under half So If you change the sending unit and fuel pump and still are having the same issue where the gas level will not read past 3/4 of a tank no matter what you do, the way to fix it is to change the Climate Body Control Amplifier Controller Module BCM
its behind the radio removal and installation took 15 min top and everything would go back to normal.
hope you guys could pass it on to the other driver.


I praise that those mechanics, Infiniti should of known how to fix this issues especially when I paid $150 to have the car diagnose. not cool from them.

 

Hello I've been having a fuel gauge issue where my fuel gauge needle is always passed full. My mechanic changed the fuel pump with sensor and it didnt work so we returned it. Would the amp unit controller fix my gas gauge issue or would it be the cluster? Please someone help, I've had this problem for almost 2 years and I never know how much fuel I have and I get stranded on road half the time. Thank you guys

 

I know I'm really late replying, and only because I'm having the same issue, but you can run diagnostics on your cluster to see if its the problem. if not, it is most likely the AC Amp.

With the car turned off, hold the trip/a/b button. While its pressed, press the ignition button twice with foot off the brake. release and press the trip button 3 times. This should put you in diagnostic mode. Holding down the trip button will move the coolant and fuel gauge to half, and letting go will move them back to 0. If they do this behaviour and look symmetrical left and right, your cluster is fine. If the fuel gauge doesn't move, doesn't go to 0 or doesn't reflect what the coolant gauge is doing, its a faulty cluster.

 

I have the same problem. I replaced both sending units but the fuel gauge stays full. You said the Body Control Module is behind the radio but when I goggle how to change the BCM it shows it by the passengers feet and does not look like the part you are showing. Can you help me out?

 

It's not the BCM, it's the AC Amplifier module. Make sure you look at yours first and find the exact number because they're manufacture year and month specific.

 

So just remove the radio and its right there? any other things I should know?

 

Nope, that's it

 

Thanks for the help guys!!! It was the ac control module. Fuel gauge finally works

 

Awesome, congrats. Glad we figured this one out. Took me a year to figure it out haha.

 

I should mention for the next peeps doing this you will need a torx screw driver to remove the module and I had to reset the air bags after cause it started blinking after, what was easy to do after a google search. I have a 2013 and I ordered one on ebay from a 2012 different part number but it worked,

 

Right, I forgot to metion that part.

 

Thanks to all just ordered AC module, gotta pass inspection next month. Fingers crossed!!

 

So, if the gauges both move up and down in sync then the problem ISN'T the Climate Body Control Amplifier Controller module - correct? Wondering because I have a 2015 Q40 that is having this problem and I am wondering if it is the sending unit or something else. Thanks in advance for any feedback and of course for the info that you've already posted - hugely helpful!

 

I think it only affects the fuel level signal, not any other gauges.

 

I'm having the same problem with my fuel gauge. 2008 G37 base.

I replaced the whole fuel pump assembly, sending unit, and AC amplifier.

AC amplifier I replaced with 2 different units. Both numbers matching. Same issue,

Is there any sort of reset that needs to be done to get it to work correctly?