QX50 Instrument diagnostic

[robski70]

I'm trying to troubleshoot incorrect fuel gauge. Both sending units check OK on Ohm meter and tried cleaning both, same result. Gauge reads well above full with full tank and stops going down at about 3/4. I put the instrument cluster in diagnostic mode using the trip button. When the instruments are in diag mode, the fuel level goes to 1/2 tank. My question is what should it go to in diag mode? Would appreciate if anyone could try it with working gauge if they just know.

Thx

[VStar650CL]

I'd assume it's the same as the '16, see MWI-37 here:
https://www.nicoclub.com/service-manual ... %2FMWI.pdf

While it's displaying the "888's" the fuel and temp gauges should go to zero. If the fuel gauge only goes to half then you have a bad stepper motor in the cluster or the controller has lost its calibration memory. You can double-check that by disconnecting the pump connector. The gauge should also drop to "E" when you open that circuit. If it stays above "E" then the problem is in the cluster.

[robski70]

Thanks for the reply. It does display E when disconnected. According to the MWI the gauge should read 1/2 tank during the self diag mode. Guess wiring harness is next to check.

[VStar650CL]

Is it possible one of your senders is stuck or tangled in an "up" position? The senders are arranged in series, so if one is mechanically frozen then you'll only get half the normal movement centered around whatever voltage is coming out of the stuck unit.

[robski70]

i had both of them out of the tank when I cleaned the contacts. Both move freely.

[VStar650CL]

It's not a matter of free movement of the float itself, sometimes they can tangle or be obstructed by the wires and get temporarily untangled when you remove them.

[robski70]

Now i got a check engine light with 0462 Fuel Level Sensor A Voltage Low. This is new wasn't there when I first noticed gauge issue. Didn't see it first time I drove car after putting sender & pump back in.