Ok, I was following my wife last night in my car and found out my Speedo is about 5 mph off. At the same time I found out my fuel gauge is 1/4 off when i ran out of gas. My question is, do these have to be corrected at the dealership or do I have to replace the speedo cluster and can I just pull the fuel sending unit out and bend the float wire to correct the fuel issue. Never had this happen before so not sure what I need to do. Any help would be appreciated. Thanks!

 

You can test for proper operation at the connector harness on top of the fuel pump, if it's sending the correct signal to the combination meter then the meter assembly will need to be replaced.

As for the speedometer, are you running the stock size tires? I don't think this ECU has the ability to reprogram a custom wheel size or speedometer correction so the issues lies either with the sensors/axle where the signal starts or at the speedometer where the signal ends. ODB2 scan the system for vehicle speed while driving and see if it displays the same value as the needle on the speedometer, stepper motor failure is not uncommon.

 

Yup I just checked. My stock tires are 215-55R17, which is what I have. So the speedo is off somehow. Is there a gear I can change to correct it or do I need to take it into the stealership to have them correct it?

 

It's a stepper motor so it requires unsoldering from the board, most folks opt for a replacement combination meter (instrument cluster). I would still verify proper signal to the speedometer before going any further just to make sure it's not a problem with the VSS at the rear differential.

 

Is the stepper motor on the cluster or is it somewhere else. The only Stepper Motor I'm familiar was on the early electronic carburetors.

 

Yeah it's mounted on the board directly behind the speedometer, these factory units are sealed up pretty tight I'm sure it would be some pretty serious work getting it replaced.

 

Thanks to the factory service manual provided on the forum, I'll check it out to make sure it's not the VSS, actually I'd prob be happy if it was and just be able to change that part instead of the whole gauge cluster. I'll report back prob next week. Thanks!

 

Has anyone reported back about changing the stepper motors on their cluster? If so, I can't find out the p/n or style of stepper motor the Infiniti uses. The only thing I can find is for the QX56. Nothing anywhere for the G35. Does anybody change these or do they just buy a new cluster when they go out.

 

Check out the final post on this page, guy had luck having someone rebuild his cluster. I'm sure replacing the stepper motor is what he did.

https://g35driver.com/forums/g35-sedan-v35-2003-06/441048-fuel-gauge-problem-detailed-5.html

 

Ok, I just read the fuel tank senders. The main sender specs according to the FSM is 3 full and 80 empty, mine was 3/71. The secondary specs fm FSM is 3/43 and mine were 3/43, so that one is ok. Now the thing is, the FSM says Approx readings, so my question is, is 71 ohms close enough or should it be closer to 80. Going to run the tank lower before filling to check it. The main was a little wrapped around the harness inside that tank, so I'm hoping mb the float was off due to interference. Thoughts anyone?

 

Run till it's near empty and retest.