How to fix fuel guage
what does it do now? stuck high, low. ,read off a bit. ? or what?
the tests are easy.
covered in the FSM 100% ( in a bad way)
see that here in chapter,called, "instrument panel"
as you can see the gauge is digital (CCD)
and the PCM (engine controller) sends fuel data to the gage via
the CDD data bus.
so the sender , may be telling the PCM wrong information.
I'd start there.
if your read page 5 it tells you the PCM sends, Empty stop data
to the gauge when the sender messes up.? DID YOURS?
does your low fuel warning lamp still work?
if not, that is clue 2 that the sender is BAD. if dead lamp.
that means sender bad, or wires TO it are bad, as in all cases, electrical..
In a real Jeep dealer, they use the DRB tool and read the sender
data directly and in 1 second, ahhh, it reads wrong.
then find the cause.
but us poor, sand crabs, we dont have DRB scanners.
we are not blessed.
but we are not helpless, not yet.
see the last chapter "wiring", see the fuel page. #
8w=20-3 (pdf 69)
see the sender
see the 2 wires,
see the colors. bingo.
what i do is, inplug the PCM (battery neg lug, disconneted)
the measure the resistance of the 2 wires.
DB-LG and BR-YL
PCM C2 -A4 and C1-c26
the sender is JUST a crude Rheostat (a wire wound var. resistor)
0 ohms (near is full) 100 (near is empty)]
if it reads infinity the line is bad. wires, connector all the way to the sender.
old data on older jeeps 86
With float in up position, resistance should be 20 ohms. With float in down position, resistance should be 220 ohm
i dont have spec. on all years.
but it dont matter.
its near zero full
and near 100 to 200 empty
and infinity dead, they all wear out and go open circuit some day.
or the connector rusts 100:1 . over bad sender.
corrosion is no rare thing on cars.
20 ohms - full
220 ohms - empty.
im scanning the internet finding others data.
The same wires can be tested on the pump side to measure the resistance of the sending unit. A low resistance of 20-30 ohms would indicate a full tank and an empty tank should be around 260-300 ohms. If the sending unit resistance tests higher or open circuit the sending unit is bad.
Apr 28, 2014 |
1996 Jeep Grand Cherokee